November 25, 2025 • 52 mins
In this classic episode of Stuff to Blow Your Mind, Robert and Joe discuss urohidrosis: the avian habit of urinating and/or defecating onto the scaly parts of one’s own legs. Find out what it’s all about… (originally published 11/19/2024)
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Speaker 1 (00:06):
Hey, welcome to Stuff to Blow Your Mind. This is
a holiday week for us, so today we have another
vault episode for you. This is going to be a
case of the urine sweats. This is an episode that
originally published eleven, nineteen, twenty twenty four, and we're going
to get into the avian habit of urinating and or
(00:27):
defecating onto the scaly parts of one's own legs. Let's
find out all about it.
Speaker 2 (00:36):
Welcome to Stuff to Blow Your Mind, production of iHeartRadio.
Speaker 1 (00:46):
Hey you, welcome to Stuff to Blow your Mind. My
name is Robert.
Speaker 3 (00:49):
Lamb and I am Joe McCormick. And today on Stuff
to Blow Your Mind, we're going to be talking about
a concept called euro hydrosis. I'm not going to do
any see roundabout introduction. I think we owe it to
you to cut right to the chase, which is that
today we're going to be talking about the biological reasons
an animal might want to poop and pee all over itself. Yeah.
Speaker 1 (01:13):
Yeah, this is gonna be one of those episodes. So
if you're not in the right headspace for this discussion,
you know, come back and listen to the episode another time.
But I think most of you are probably on board
for this.
Speaker 3 (01:25):
So before we get to the reasons why, I think
we should start with just a kind of visual introduction
and observation, and it is that if you look at
some long legged birds strutting around in their natural habitat,
maybe wandering in the grass or on the rocks, foraging
for food or getting ready for mating, you will sometimes
(01:45):
see their legs covered in a pale residue. And Rob,
I'm attaching some images for you to look at here
in the outline, but people at home, you may want
to look these up for yourself when I give you
the names. So the examples I'm about to mention would
be three stork species. One is Seconia episcopus. This is
the wooly necked stork. Another one is Micteria leucocephala, which
(02:10):
is the painted stork, and another is Leptoptalus creminifer, the
marrabou stork. Now, these are all storks with long, thin legs,
I would say very roughly, you know, body length or
longer standing in an upright posture, and in the pictures
I've provided for you, Rob, these come from a paper
(02:32):
that we're going to talk about in just a minute,
you can see in patches that the legs and feet
have a natural pigmentation. They've got maybe a gray or
brown or black color on the skin of the legs
and feet. But in all three of these images, the
legs are mostly covered in some kind of white substance.
(02:52):
And if you had to guess what it is, what
would you think it is? Indeed, what you're probably thinking,
it's not.
Speaker 1 (03:00):
It's not some sort of a glittery bomb, right, it's not.
It's not any kind of as we've discussed, it's not
clothing that they're wearing here over their their long legs.
Speaker 3 (03:09):
It's something else, that's right. It is the bird's poop. Technically,
in mammal terms, you might want to say it is
both urine and feces, because birds deal with their excreta
in a kind of different way than mammals do. They
basically do it all in one go. It's not a
separate poop and p It's all one thing.
Speaker 1 (03:29):
Yes, the Glory of the Cloaca, which long time listeners
to Stuff to Blow your Mind have a fair amount
of familiarity with, though I don't think we've done an
episode on the kloaca recently. An old episode on the cloaca.
Speaker 3 (03:42):
Remember it's a classic from many years ago. I think
you and Julie did some cloaca.
Speaker 1 (03:47):
Yeah, yeah, and then it's come up, you know, it
comes up anytime we're potentially talking about reproduction and digestion,
when you know, concerning birds and other animals. Sometimes it
pops up in discussions of prehistoric cree as well.
Speaker 3 (04:01):
That's right. So with these animals, with the bird or
reptile lineage, you're going to be doing digestive waste, renal
system waste and reproduction is just all going in and
out the same hole, the kloaeca. So anyway, I got
interested in the concept of eurohydrosis, the idea that birds
would be intentionally having an adaptation to excrete waste all
(04:24):
over their own bodies, all over their own legs, and
so I was looking for scientific sources about this. So
I found a paper from twenty twenty one that lays
it all out pretty well. This is a paper in
the journal Scientific Reports, and I apologize if I pronounced
any of the author's names wrong. Here. It is by
Julian Kabeo Verguel, Andrea Soriano Redondo Auxiliadora Viegas Jose A.
(04:49):
Maseroje M. Sanchez Guzman and Jorge S. Gutierrez, and the
paper is called eurohydrosis as an overlooked cooling mechanism in
long legged birds. So basically all animals on Earth need
to regulate their internal body temperature, and there are a
lot of reasons for this. Of course, we're all basically
(05:10):
different types of water bags moving around and reproducing ourselves.
So at the extremes you need to manage yourself as
a water bag. You need to prevent your water content
from freezing solid or turning into steam. But beyond those extremes,
animals also need to keep their body temperature within a
fairly narrow range to protect cellular function and facilitate the
(05:32):
chemistry of metabolism, like there are certain enzymes in the
body that don't work right if they're outside of a
certain temperature range, and so forth. And there are broadly
two different ways that an animal species can be oriented
with respect to the regulation of body temperature. These are
ectothermy and endothermy. Endotherms also known as warm blooded animals
(05:53):
generate their own internal heat from metabolism, so they burn
food energy and use homeostatic mechanisms like shivering and sweating
and so forth to keep body temperature within a very
tight range. Mammals and birds are generally endotherms. They primarily
regulate their temperature with internal mechanisms. Ectotherms, on the other hand,
(06:16):
sometimes called cold blooded animals, regulate their body temperature mostly
with the help of the outside environment. So these are
the animals that you would think of as sun basking
or cooling in water in order to manage their body temperature.
Ectothermic animals include most reptiles, amphibians, and fish. Though to
be clear, the cut between ectothermy and endothermy is not
(06:39):
a clean cut. There are a lot of kind of
blurry cases in between, just sort of a generally helpful distinction. Now,
there are advantages to each of these major strategies. We
could come back and go deep on this someday, and
we've talked about it somewhat in the past, I believe,
But a very simplified version is that indotherms animals that
primarily rate their own heat through metabolism, they can do
(07:03):
a lot more. They can sustain more muscular activity, they
can grow more powerful brains, they can survive in a
greater range of different climates, you know you don't usually
see like reptiles and extremely cold climates and so forth.
But they also require a lot more food. Ectotherms are
efficient because they don't leave the motor running all the time.
(07:25):
They can usually go much longer in between meals and
can survive rough patches by kind of going dormant. Now,
because this paper is focused on birds, we're in the
domain of the indotherms, the warm blooded animals that primarily
generate heat through their own internal metabolic mechanisms. But even
endotherms can't regulate everything internally, and the authors begin the
(07:49):
paper by discussing various ways that endothermic animals do still
have to protect themselves from external heat stress, from getting
too hot because the environment is too hot. And some
of these defense mechanisms against overheating are physiological and some
are what you'd probably call behavioral, and the authors say
(08:10):
that typically the first response, the first priority response, in
the responses you go through when you're encountering heat stress
is behavioral, and this could involve the selection of cooler microclimates,
going to cooler places from warmer places, or what they
call heat dissipating behaviors, And there are many different kinds
(08:31):
of heat dissipating behaviors in nature. This could mean something
as simple and as familiar to us as reducing physical activity.
You know, it's hot out, you stop moving around so much,
or moving out of the sun and into the shade,
or things like getting in the water for a swim.
Being submerged, even in what feels like fairly warm water,
(08:52):
actually removes heat from the body quite efficiently. The author
is mentioned later in the paper that the thermal conductivity of
water is twenty five times that of air. So you're
you might have had this experience before where you know,
even in a pool that doesn't feel very cold, the
water feels nice and warm. You spend too long in
the pool, you really will start to chill out and
(09:15):
you need to get out of the water and warm up.
Speaker 1 (09:17):
Yeah, so you can basically could basically like roleplay all
of these like you almost have like an innate pull
towards these various thermoregulation options. You know, if we were
to position you, say, you know, a nice pool patio
on a hot summer day, what are some of your options?
You know, do you choose the umbrella, do you choose
the pool, do you choose the shade of the house
(09:38):
and so forth.
Speaker 3 (09:39):
That's right. And then there's another class of heat dissipating
behaviors which could be called like posteral adjustments, and this
could be just positioning the body in different ways to
maximize how much heat it is getting rid of. One
example is spreading out the body tissues to increase your
surface area. So think about how when you're cold, you
(09:59):
kind of try to s shrink down, don't you. You
try to shrink your body into a ball and reduce
your surface area. You might hug your arms into yourself
and kind of kind of crouch. But in the heat,
if you're overheating, you don't want your legs touching each other,
and you don't want your arms touching your body. You
want to splay out maximally to have maximal surface area,
which means heat can escape your body with the greatest efficiency.
Speaker 1 (10:22):
Or you might want to fan out your neural spine
sale for a yes, or if you want to regulate
your temperature that way. If you have a neural spine sale,
I'm not going to presume everyone has one.
Speaker 3 (10:32):
Or if you're a bird, you might want to fold
unfold your wings, hold your wings out to let you
know heat radiate that way. You know, different animals exactly
the spine sales. This is a great example. You know,
different animals have different ways of increasing their surface area
and radiating more heat. Now, if the endothermic animal cannot
escape heat stress with just the behavioral responses, it has
(10:54):
to switch gears into what the authors call rapid physiological adjustments.
This is things that the body does we would usually
think of as involuntarily to try to remove heat faster.
And these can vary across different types of animals, but
it could include things like in humans, sweating, in other animals,
(11:14):
panting or increasing the breathing rate to dissipate more heat
from the lungs and the respiratory system. Now, the authors
point out that in birds, one of the most common
physiological mechanisms for removing heat is what they call panting.
I've seen some sources reject that terminology, maybe because they
(11:34):
think it incorrectly implies it's the exact same thing that
dogs do, But it's similar either way. For birds, panting
involves rapid breathing with an open mouth. They might hold
the bill open and breathe in and out very rapidly
to purge heat through evaporation from the warm, moist tissues
inside the mouth, throat, and lungs. This is also sometimes
(11:56):
accompanied by another response called gooler fluttering u laar fluttering,
which means like they would, the bird will vigorously vibrate
the muscles and membranes inside its throat while panting to
further increase evaporation and the purging of heat. Now, these
physiological adjustments, they do work. They will purge heat from
(12:18):
the body and help avoid hyperthermia, help the animal cool down,
but they're also very costly. They're costly and thus risky
to the animal because they can waste important resources like
energy and water. Birds can lose a lot of water
through panting and fluttering, and in addition, the authors mentioned
(12:39):
that panting in birds can force potentially undesirable changes in
blood chemistry. So, if you're an animal in the wild
fighting for survival, you know you have these physiological mechanisms,
these sort of rapid body adjustments that you can rely
on if you have to, but you would like to
avoid them. You would like to avoid going into these
(13:00):
wasteful physiological protections against heat if you can help it,
and the more efficient behavioral methods should be your first
line of defense. So for a human analogy, it's usually
it's going to be less costly to your body to
just get into the shade and get out of the
heat than it is to start sweating bullets. In their introduction,
the authors of this paper introduce a concept from zoology
(13:22):
called heat dissipation limit theory, which argues that in indotherms,
the problem of how to deal with excess heat produced
by metabolism limits how much energy you can take in
and by consequence, limits reproductive output. So the author is
right that under this theory, heat dissipation behaviors could really
(13:43):
be crucial to the evolutionary success of a species because
they allow more chemical energy to be devoted to foraging
and reproduction and things like that, rather than to physiological
mechanisms simply for getting excess heat out of the body.
And the author is mentioned that the sort of research
context of this paper is that thermoregulatory behaviors and animals
(14:05):
are increasingly being studied because of the current and future
increases in heat stress on wildlife due to global warming,
where the ability of an animal species to deal with
heat stress without resorting to costly physiological mechanisms may be
the difference between adaptation and extinction, So this is something
that is probably just going to get more and more
(14:26):
attention from people who study wildlife, especially as the heat
stresses of environments are changing more rapidly. Now, another interesting
fact about how birds protect themselves against overheating has to
(14:49):
do with what the authors call quote unfeathered and well
vascularized appendages, meaning parts of the body that are bare
so not covered in feathers, and parts of the body
containing a lot of blood vessels. And examples here would
be the bill, the bird's bill around the mouth, and
the legs. Because these parts of the body are typically
(15:10):
not insulated by feathers and lots of blood flows through them,
and for these two reasons, these parts of the body
can be utilized pretty well as what the authors call
thermal radiators to purge excess heat, and this is especially
the case for storks. The storks belong to the in
scientific classification, they belong to the family Sickniady, which storks
(15:35):
typically have long, bare legs and most often live in
warm or hot climates with little shade. So storks have
an internal mechanism for making use of these thermal radiators
in the body for making use of the long legs
for temperature management. Storks can actually alter the blood flow
(15:56):
to their legs, constricting the blood vessels down the when
it's cold out so less blood is flowing through and
there's less heat exchange, and then dilating the blood vessels
in the legs when it's hot, promoting more heat loss
from the body down in the legs. But in the
case of storks, the use of the legs as thermal
radiators goes one step further, and here's where we get
(16:17):
back to the topic for today. Eurohydrosis the author's right quote. Notably,
storks can deliberately excrete onto their legs when exposed to
increasing environmental temperatures, a phenomenon known as eurohydrosis. When overheated,
storks repeatedly direct liquid xcrita toward their legs, only one
(16:39):
leg at a time, which usually evaporates before reaching the toes.
So it's hard to imagine this from a human perspective,
but the more you think about it, the more it
does make biological sense. Imagine you're out in the sun
on a blazing summer day. The heat's really getting to you.
You have a few options to cope. You could stop
moving around and fly down in a chair. You could
(17:01):
get out of the sun and into the shade. You
could hop into a pool. Or if those options are
not really available to you at the moment, you could
poop all over your own legs, one leg at a time,
and then hope that that helps cool you off.
Speaker 1 (17:15):
Granted, there are certain consistency challenges here. Yes, yes, some
dietary adjustments might be necessary in order to ensure this
as a viable tactic for human beings. But I think
we all have great imaginations we can see it.
Speaker 3 (17:30):
I'm not recommending this as a tactic for human beings.
I don't know that this would work for a human.
It might be a bad trade off. But it works
for the storks. But the question is how does it
work for the stork? How does it cool the body? Well,
it is actually the same physical principle at work as
many other thermoregulation techniques in nature. It is evaporative cooling.
(17:51):
We've talked about evaporative cooling and a number of contexts
on the show before. I think we did an invention
series on the history of air conditioning. The air conditioning
where we talked a lot about evaporative cooling, and it's
come up in a biological context as well. But the
short version is that the phase transition from liquid water
into water vapor requires a lot of heat energy to
(18:14):
take place. So water that is evaporating into the air
cools down very rapidly and in turn cools whatever it
is touching, such as your body if it's on the
surface of your skin. And if you ever want to
do a simple experiment in your home to see evaporative
cooling at work, you can try. This is kind of fun.
You can get two bottles of water at the same
(18:36):
temperature room temperature bottles of water, and you put them
both in front of a fan, and now one you
just sit there with nothing, you know, by itself, but
the other one wrap the bottle in a wet towel,
set them both in front of the fan, and then
come back in like half an hour. The regular bottle
will not have cooled off significantly, but the bottle that
(18:56):
you wrapped in a wet towel will be very cold
because as airflow from the fan causes the water in
the wet towel to quickly evaporate, it will suck heat
from the water in the bottle and make it cold.
I think this is an old trick that like people
traveling in desert climates, you know, without artificial cooling used
to use where they would, you know, they'd have like
(19:18):
a big jug of water, like a big skin of water,
and to keep it cool as they're traveling in the
hot desert sun, they would also get like a cloth
and wet it at the beginning of the day and
wrap it around the outside of this skin of water.
And as the water evaporates from the hot cloth on
the outside through the day under the hot sun, it
sucks heat from the water inside and makes the water
(19:39):
very cold. And evaporative cooling is why sweating cools the body.
You know, as sweat evaporates from your skin, it steals
heat energy from your body and it cools you off. Now,
of course, sweating has a downside, which is that it
causes you to lose water and electrolytes. So when you're
hot and sweaty, it's very important to keep hydrated to
(20:01):
compensate for the water loss. Exercising in the hot sun
one oh one, you got to drink lots of fluids.
The same is true for birds. Now, birds don't sweat,
they don't have sweat glands, they can't sweat, but they
do have their own evaporative cooling techniques, and as we
talked about, the panting is one of those techniques where
they can use evaporative cooling in their respiratory system with
(20:23):
the open bill rapid breathing, and eurohydrosis is one of
these techniques. The author's right that eurohydrosis is relatively rare
among birds because it requires ready access to a lot
of drinking water, but plenty of bird groups have been
observed to do it. They list New World vultures, storks, condors, gannets,
(20:46):
and boobies. And eurohodrosis has been known about for a
long time, but the authors say there still has been
relatively little investigation of what exactly are the environmental and
physiological factors that determine it, like what causes one bird
group to use eurohedrosis and another group do not use it.
(21:08):
So the authors came up with a systematic way of
looking into this. Now, this particular study relied on essentially
repositories of scientific media, like imagery of birds from various
field locations that was associated with metadata, so that you
could try to correlate like images of birds doing certain
(21:28):
things and the environmental data about them. So this was
not direct field test with variables that the authors could manipulate,
but they were just trying to establish correlations between like
environmental factors and factors about the bird's bodies, along with
observations of do these birds poop on their own legs
(21:48):
or not? So what environmental factors did they find correlating
with the use of eurohydrosis by storks? The authors found
that high temperatures, high solar radiation in higher air humidity,
and low wind speed were all factors that would increase
the baseline heat stress risk for an endothermic animal, and
(22:11):
storks in environments with all of these conditions were more
likely to engage in eurohydrosis. They also found that it
was more common among stork species that forage on dry
land as opposed to those that commonly inhabit water bodies
and forage by wading, which kind of makes sense to me, Like,
if you can get your legs wet without pooping on them,
(22:32):
all the better, right, But some storks are not in
a position to spend as much time hanging out in
the water.
Speaker 1 (22:39):
Right right, Or you're dealing with water that's very shallow. Yeah,
you know, we've all seen storks in the wild, I think,
and yeah, yeah, sometimes they're in very shallow waters.
Speaker 3 (22:49):
Now, even storks that sometimes wide in water do apparently
use eurohydrosis, just less often. For these species. It may
be more limited to times when circums stances create a
higher heat risk, such as during reproduction when they need
to be out of the water in the heat for
extended time. But anyway, the authors say that the hypothesis
(23:09):
that eurohydrosis correlates to open and warm habitats was confirmed.
Birds that sort of live out in the open in
hot places, they're the ones that are going to be
more likely to do this to help cool their bodies. Now,
there were some other hypotheses that had been put forward
by these authors and other authors that were not confirmed
in this research. It had been hypothesized that stork pigmentation
(23:34):
would be correlated to the use of eurohydrosis. The ideas
maybe that birds with darker pigmentation absorbed more heat from
the sun, but this was not supported by the survey.
They did not find that correlation. It had also been
hypothesized that eurohydrosis would directly correlate to the latitude where
birds live, with tropical species practicing it more. This was
(23:57):
also not strictly supported, though again there's some complications because
some of these birds, you know, they will travel, live
at different latitudes different parts of the year, and again warmer,
more open environments did predict it, it was just not
strictly latitude. Another thing that was not supported was a
hypothesis about body mass. This was something that the authors
(24:19):
of this paper predicted. They thought that higher body mass
would predict more eurohydrosis because the animal would have more
water reserves to take advantage of, Like if you're you know,
you're a bigger animal, you can drink more water, store
more water in the body. You can also you've got
more to you know, to waste in pooping on your
own legs to cool off. But this was actually not
(24:41):
the case. This might have to do with the fact
that these storks all had access to water bodies for
regular drinking, even if they didn't spend a lot of
their time waiting around in that water, so maybe internal
water stores were less of a concern. Looking beyond storks,
the authors note that even other bird gre groups that
practice heurohydrosis, like New World vultures, boobies, and gannets. They
(25:05):
all tend to breed or forage in hot, open land
areas under the sun, and they also tend to have
relatively large and highly vascularized legs, so there seem to
be some common environmental and physiological pressures at work. Now,
some other interesting observations from their conclusion I thought one
was that when comparing different ways of cooling the body
(25:28):
at the cost of energy and water reserves, the authors
conclude that eurohydrosis is actually cheaper than panting, which was
kind of surprising to me that that was counterintuitive, but
they said this is supported by the fact that birds
who have the adaptation tend to engage in leg pooping
at a lower temperature threshold than the temperature threshold for panting.
(25:51):
So I think kind of like how if you're a human,
humans will typically resort to like changing into short sleeves
before they will resort to like jumping into ice water bath.
You know, one is like a more severe costly activity
than the other, And it seems like for these birds,
panting is the more severe, more costly, and risky activity.
(26:12):
The authors also note that other animals, apart from birds,
use alternative evaporative cooling methods, not just not just sweating
like we do. They say some mammals produce excess saliva
when hot and then use evaporative cooling through the mouth
or even cool the body by like drooling or licking
on themselves on the outside and then allowing that saliva
(26:33):
to evaporate. Rob I know, you've got an alternative evaporative
cooling method to talk about in a minute. But they
end up saying that there could be some tradeoffs involved here.
There's possibly that this is not a strong not something
they strongly established, but a possibility is that there could
be a tradeoff between mate signaling based on the pigmentation
(26:56):
of bird legs and the cooling benefits of eurohydrosis. But
this is yet to be fully explored. But the idea
here would be if this were the case, that it
helps you advertise mating fitness better, if like the correct
pigmentation on your legs is showing, and that by pooping
all over your legs, this like changes the way you
look and sort of downgrades your mating appeal. So there
(27:19):
could be some push and pull there, but that wasn't
very well established. But more briefly, I did want to
mention a second paper that involved three of the same
authors as the previous paper, because it had some interesting
follow up on this and involved a more direct method.
And so the second paper was by again three of
the same authors, Kubeovergel, Viegas and Gutierrez, and this one
(27:44):
was called Keeping Cool with Poop. Eurohydrosis lowers leg surface
temperature by up to six degrees celsius in breeding white storks,
published in Ecosphere in twenty twenty three. And this study
was a direct attempt to measure that the magnitude and
dear duration of the evaporative cooling that you get from
eurohydrosis in free ranging birds. The study used observations of
(28:08):
eurohydrosis in white storks or Seconias econia, paired with thermal
imaging and microclimate measurements to see like exactly how much
benefit the leg pooping was providing. Now, this next part
in the abstract did make me laugh. They write, quote,
we show that eurohydrosis can reduce leg surface temperature by
(28:29):
up to six point seven degrees celsius, which is actually
four point four plus or minus one point zero four
degrees celsius. Yet its cooling effect was of short duration,
lasting no more than two point five minutes and decreased
with time since defecation. Which actually that makes sense, right,
because like, if you're trying to work through evaporative cooling,
(28:51):
as the bird poops on its leg, it will be
very it will have a great cooling effect while the
poop is still very wet, but then as it evaporates,
it will dry up, and then it will provide less
of a cooling benefit and may even have some negative
effect in fact, if it like cakes on.
Speaker 1 (29:07):
You know, let's keep all of this in mind as
we perceive, right.
Speaker 3 (29:12):
So, but then there's the second second thing here. The
selection continues quote. Thus, for eurohydrosis to significantly contribute to
heat dissipation, storks must perform it repeatedly when overheated. So
the leg pooping must go on and on, and it
turns out it does. The authors found that the white
storks here can poop on themselves eleven times per hour.
(29:36):
And I did a little math there. So with like
two point five minutes of cooling with each blast, that's
twenty seven point five minutes of cooling per hour. If
they do it eleven times, almost half of the time
of the hour is in cooling. Mode. So the authors
estimate that eurohydrosis can cover quote four percent of the
daily field metabolic rate for an adult stork. Wow.
Speaker 1 (29:59):
So it's like any like cooling system in a house
that might it might not be on all the time.
That would probably be just biologically impossible, but it's going
to keep coming on periodically to try and keep the
temperature down.
Speaker 3 (30:11):
Yeah, that's a great comparison. It'll trigger repeatedly over time
to kick off little short periods of cooling, and then
the body temperature will come back up again, and then
the bird will release the excreta again and it will
set off another short period of cooling, and it'll go
back and forth. Now, I just did want to I
mentioned this on the earlier study, but I did want
(30:32):
to emphasize again. Unless you think, oh, you know, this
is just silly, this is actually interesting and relevant knowledge,
and will things like this will be of increasing importance
to wildlife and conservation biologists over time. The author's right quote.
Gaining knowledge about behavioral thermoregulation in the heat is therefore
crucial to better predict the future persistence and vulnerability of
(30:55):
species under different climate warming scenarios. A lot of these
species are going to be living in places where the
local climate is increasing in heat over time. That's increasing
the heat stress on animals that live in the wild,
and some animals will be better or worse able to
deal with it than others. There was another question that
(31:24):
came out because I saw some stuff online in discussions
about eurohidrosis that was about possible other functions. It seems
pretty clear that certainly in storks, it's playing a role
in cooling the body. But is eurohidrosis just to cool
the body or in some species, could it be playing
(31:45):
another role as well? Like I saw some ideas that
it could possibly have an antibacterial function.
Speaker 1 (31:51):
Yeah, and that brings us back to the gross and
wonderful world of vultures. These splendid kings and queens who
keep our s it's clear of carcasses and in general
are just great decomposers there. There were a few in
our neighborhood not to just a week or so ago.
They were disrupting traffic. But you know, as we went
(32:12):
by them, we saluted them because they were they were
doing the lord's work out there.
Speaker 3 (32:16):
They're worthy of our respect. Yes.
Speaker 1 (32:18):
So, yeah, there's this idea that various New World vultures
are engaging in this kind of you know, possible euro hydrosis,
but maybe not for temperature control purposes. That you know,
they've been observed to do it when it's cold, they've
been observed to do it when it's warm, So what
could the purpose be. And there is this idea that
(32:39):
it is essentially kind of like when we reach for
a container of a hand sanitizer, except for the vulture whose,
of course, you know, it's it's getting its talons into
various you know, grotesque feasts there on the side of
the road or in the wilderness and so forth. Occasionally
it makes sense to to sam ties those legs with
(33:01):
an eye, perhaps with a nice you know, coloacal wash.
And so that is the theory that there is an
antiseptic nature of vulture defecation and that it, you know,
especially would be important for various scrapes and cuts on
those appendages. And so I was reading about this in
a twenty twenty two book, Vultures of the World, in
(33:22):
which the author Keith l builds and points out that
at the time, at any rate, the antiseptic nature of
vulture defication had not been like tested to the fullest.
So it's still kind of an open question, but this
does seem to be a strong argument, again based in
large part of the fact that they do seem to
(33:43):
do it both in summer and winter, suggesting that disinfection
might be at least an important part of the equation
for like turkey vultures. Okay, now, an interesting fact about this.
I was not familiar with this, but the author here
points out that in US, in US and Canada at
any rate, vulture researchers are prohibited from using leg bands
(34:05):
on turkey vultures because there's a risk of uric acid
building up and cementing around the leg band, because again
they're pooping and peeing down those legs. If you have
a band there for tracking purposes, it could you know,
it gets caught there, it drives there, it's cements there,
and this could effectively hobble the bird over time. Eventually
(34:27):
it's like too big of a weight for them to
fly off with apparently, or at least you know, it
would get in the way of their they're flying, in
their ability to carry out their daily activities. So fortunately,
there are other methods for tracking them, things like wing
tags and the like. But putting a leg tag on
them as a no no. Now, before we get away
(34:48):
from birds, I do want to point out that in looking,
I'm always interested to see if there's any kind of
mythological or folklooric tie in to a particular topic, And
I really wasn't expecting much here, but I did find
mention of this in connection to Amazonian mythology via a
book titled an Amazonian myth and its History by Peter
(35:11):
Goal that came out in two thousand and one. So
the story involved here is referred to as the Sun,
and it entails a character who is at one point eviscerated,
but in a nice way, like in a like a
polite mythic way, like he's asleep, and the creatures that
(35:32):
are working for him like remove his intestines. But at
any rate, the story involves a character who's eviscerated becomes gutless,
and by becoming gutless, can now eat and drink all
he wants, but can also never be satisfied. And this
is a story that Gal says is apparently connected to
observations of the wood stork who appeared gutless because they
(35:56):
are constantly excreting waste. You mentioned like how often per
hour they are excreting in order to cool those legs down,
and it can lead to this observation it's like, well,
this animal poops all the time, and we don't do that,
like we you know, we know exactly, we know more
or less what's happening when we consume food and it
becomes nourishment and so forth. Perhaps the stork is not
(36:18):
giving it time at all, is just going straight through.
And therefore, you know, there's just these kind of you know,
ravenous but unsatisfied creatures.
Speaker 3 (36:28):
Interesting. Now, I didn't come across a poop count on
the wood stork, but in that one study, yet there
was the white stork, and it was up to eleven
times per hour. Wow, that's a lot.
Speaker 1 (36:39):
So the myth, as recounted, apparently involves a man who
has enslaved the wood storks to do his bidding, but
then while he's asleep in the canoe, they remove his intestines,
and they intestines and they like hang them over the
side of the canoe, and when he wakes up, he's like, hey,
what's this stuff here? They have carently don't say anything,
(37:00):
so he throws it out and then the storks tell
him later they're like, oh, yeah, by the way, those
we are intestines. So as I understand that what we
have here is we have an observation of nature, an
incorrect hypothesis or a very loose hypothesis that may be
concerned more with the mythic purposes of the tail as
opposed to anything else. And then this bleeds into an
(37:24):
anatomical mythology that presents something almost like a hungry ghost,
you know, this idea of a being that cannot be
satisfied because his digestive capabilities are just not intact, and
that perhaps that's what we see when we see these
storks as well.
Speaker 3 (37:44):
Interesting. I mean, I guess that does sort of tie
into the observation that the storks most likely to engage
in this are the ones that are going to be
out in the sun on dry land in the heat,
but also birds that have ready access to drinking water,
and that this would probably not be a good adaptation
for a bird species that had to, you know, that
(38:04):
had to conserve water resources maximally and did not have
ready access to water bodies. Yeah.
Speaker 1 (38:10):
Yeah, I didn't have enough time to really dive into
this text, but it's out there. If anyone else wants
to look into it again. The author is Peter gow
who lived nineteen fifty eight through twenty twenty one. He
was a social anthropologist who worked a lot in the Amazon.
Speaker 3 (38:26):
Interesting story, Yeah, yeah, I also was. I did not
think there would be a eurohydrosis related myth.
Speaker 1 (38:33):
Oh, but here we are. Let's see other animals. Though,
interestingly enough, we also see this in some aquatic mammals.
The main example that I was reading about in a
paper that you sent to me, Joe, is the southern
fur seal or arctocephalus. This is this means bare head
(38:55):
because we're talking about Antarctic fur seals here. These are
furry looking critters adapted to thrive in very cold waters. However,
as Roger L. Gentry discusses in the nineteen seventy three
paper thermo Regulatory Behavior of Eared Seals, this published in
the journal Behavior, they have other means of thermoregulation that
(39:16):
become necessary when these well insulated creatures are out of
the water and caring about on the shore, on the
rocks in the sun.
Speaker 3 (39:25):
Ah Okay, so this might be a different situation than
the storks living in like a really hot climate under
the direct sun. I mean, I guess you could still
have the sun beating down on you. But the issue
here would be that the seals are very well adapted
to the cold, and so in cases where they're under
the sun and it's not very cold, their heat conserving
adaptations are working against them.
Speaker 1 (39:48):
Right And the situation where this becomes essential, especially for
the males, it has to do with their breeding period,
because they live a lot of their lives in the water,
but they they come on to land, you know, during
the breeding period, and it's very important for a male
to hold down his territory. So there's a lot of
(40:09):
fighting and squabbling for territory and for females, and it's
a it can be a real endurance game for the
males of you know, various seal species species because they're
having to constantly fight and at the same time they
have to maintain acceptable body temperatures, they have to thermoregulate,
and they're not in the water at this point. The
(40:30):
water is the author points out, the ideal place for
this creature to cool down. But you're fighting a territory war,
in a mating war up here on the rocks. So
getting back in the water is something you can do,
but that is going to be like your last resort
because you're giving up territory at that point, so you
(40:52):
have to do other things. So Jenry discusses how, especially
during the high temperatures in these environments, you'll see a
few different behaviors. So on one hand, they will seek
out shade or shade cooled rocks, which you know, kind
of the same thing. But it's essential to note that
rocks of course heat up in the sun, so being
in the shade is one level of protection, but also
(41:15):
being on rocks that are either currently or have just
previously been cooled by the shade is also worth thinking about.
And so according to Gentry, during higher temperatures, these seals
have been observed to stand on all fours and then
annoy their flippers and bellies with urine, with the back
of flippers being the key, because then they'll lay on
(41:38):
one side and extend their now wet rear flipper into
the air, and this will be the way they carry
carry out some evaporative cooling. He also notes that the
males seemingly drink more water in the surf during this
time period in order to provide more urine for thermoregulation
when they're out on the shore. So, coming back to
(41:59):
what we were talking about with the with the storks,
if you're going to engage in something like this, you've
got to keep you got to keep the fluids flowing.
Speaker 3 (42:07):
That is so interesting imagining like the sort of the
chain of preparations there I'm thinking about, So the male
seals like tanking up with water to get ready for
one of these one of these like breeding season things
where he knows he's going to be out under the sun.
Speaker 1 (42:21):
Now, this is also interesting to think about for me
because I did get to see Galapago's fur seals carrying
out carrying out their their various activities on the beach
when I was down at the Galapagos Islands, and I
didn't even know to look out for any kind of
urination going on.
Speaker 3 (42:38):
I did.
Speaker 1 (42:39):
I don't think I saw any like actual throwdowns between
male seals, but I did get to see like some
of what they're up to. So yeah, I wish i'd
known to look out for this.
Speaker 3 (42:51):
What does it look what does it look like some
we're just trying to like stake out good territory.
Speaker 1 (42:55):
Yeah, you'll see like a big male and a bunch
of females and then you know, basically trying to hold
down the territory of this part of the beach with
these females. And then occasionally here's some other male seal
coming that is going to contest this situation, and then
you know, there are various little squabbles about where the
females are getting to lay about as well. And then
(43:18):
you know, sometimes and then this is also inevitably happening
or a lot of the time, it's happening on beaches
that where people are also hanging around, so they're also
human tourists, so there's a lot of and of course
when the seals decide they want to go somewhere, it's
like it's time for the humans to move.
Speaker 3 (43:36):
Don't mess with seals, folks.
Speaker 1 (43:37):
Yeah, but sometimes they could be a little like at
one point, I was just sitting there with my family
and there was like a smaller, very loud female seal
and she just decided she needed to set where I was,
So of course I moved and then she sat there
for a little bit and kind of you know, catterwaulled
a bit, and then she moved on elsewhere. But it
was like I don't know. It kind of felt like
(43:57):
she was being a little petty, but this beach belongs
to you. I'm just visiting, very magnanimous. Yes, hey, just
a quick post publication note. I want to insert here
Everything that I was saying about the fur seals is
correct according to my research. But in the heat of
(44:18):
the moment, I mentioned the Galapagos, and I mistook my
memory of Galapagos Sea lions for Galapago's fur seals. So
sorry about that. My apologies, but I did want to
throw in this post publication correction here for anyone who
listens to the episode later. Yeah, I didn't have anything
(44:41):
about the Galapagos in my notes. It's just as I
was going through this part of the episode, it stirred
a memory, and as is sometimes the case with memories
that are recalled from the depths, sometimes it comes up
with a little bit of incorrect information applied there. So,
without further ado, let's get back into the episode. Now,
(45:01):
speaking of the Galapagos, this does bring me to the
next question that I had, because when I was in
the Glapagos, I did just a little bit of snorkeling
in very cold waters, and I was wearing a dive
suit because it gets cold. And if you've ever gone
diving or done scuba diving or snorkeling and you've worn
(45:23):
a wet suit and the water's been cold, you might
have done what a lot of people have done what
I did as well, and that is urinate in the
suit while you're in the water to warm things up
a bit. This instantly came to my mind when we
started getting into this, because, yeah, like this seems like
an example where humans can get in on the euro
hydrosis action, right, sort of in the opposite direction, in
(45:47):
the opposite direction, right, you know, can we just pee
in our dive suits in order to warm things up?
And you know, I was able to find a full
article about this on dive si dot com. That's Scuba
School's International.
Speaker 3 (46:04):
That's beautiful. Well what's the word? All right?
Speaker 1 (46:07):
So yeah, I didn't know what the what the full
scoop on this was. And I'm not like a big
I'm not a scuba diver and i am not a
wetsuit person, so I didn't even know what the accepted
wisdom was here. But the authors of this article point
out that, yeah, this is kind of like common lore
among divers and historically to scuba divers that that if
(46:27):
you get in a little cold, will pee in your
suit and then'll warm things up a bit. And they
point out that due to the mammalian dive response you
might need, you might have a heightened need to urinate
in this environment because a submerged mammal is going to
experience a slowed heart rate during free diving, especially, it's
going to narrow blood vessels and the extremities, and blood's
(46:48):
going to shift to the core parts of the body,
all in order to conserve oxygen and maintain blood flow
while holding one's breath. But more blood ends up going
to the core and then via the kidneys. This increase
the urge to urinate. So you might find yourself in
a situation where you're like, Wow, I just got into
the water off the boat, it's cold, I need a
(47:08):
pee anyway, Why don't we warm things up a bit?
And so yeah, they point out that this is a
common bit of diver's lore, and the article states quote
the wet suit itself works by trapping a thin layer
of water between the neoprene that's a synthetic rubber and
the skin, which the body warms. This layer serves as insulation,
(47:28):
keeping the diver warm in cold water. When a diver
urinates in their wet suit, the initial warm sensation comes
from the body warmed urine. However, this effect is fleeting.
Speaker 3 (47:39):
Nothing gold can stay.
Speaker 1 (47:41):
I mean in this we do kind of come back
to the situation with the storks, right, I mean that too,
is fleeting. Is a cooling burst that will have to
be reapplied. I think the problem with divers is that
you probably don't have that many goes at it here, right,
you probably? Oh? I mean, how many times can we
you urinate in your suit on a given dive or snorkel.
(48:05):
I could be wrong, but I have a feeling knowing
my body that truly it's just one, maybe two, but
not enough to not not eleven times per hour.
Speaker 3 (48:15):
Yeah, And if I'm understanding the dynamics here correctly, it
even then, like it's still just a sensation of warming.
Your body is not actually getting warmer from this, Like
you're you're losing warmth by peeing, But it's it feels
warm on the outside.
Speaker 1 (48:32):
Right, You're gonna get that. And I can testify to this. Yeah,
you get you get a warming sensation, but it is fleeting,
they point out, because the urine quickly cools and things
that will then actually feel colder when this cooling occurs.
You know, it's it's kind of like when you first
get into the cold water to swim about. It's like
it can be shocking, takes your breath away, but then
(48:52):
you get used to it and you carry on. When
you when you pee your suit in order to warm up,
you kind of like recreate something like that scenario again.
We're like, oh, now now it's cold again. Because and
part of this is the wet suit is not waterproof,
it's permeable, so outside cold water will directly cool the
layer of spreading warm urine in the suit. Now, all
(49:13):
that being said, the article stresses that ping in your
wet suit is a common practice, and it is it's
not harmful. You know, you may have some hygienic or
some comfort concerns about it, but basically all they really
advise on this is, look, if you do it, fine,
but just you want to make sure you wash out
your suit afterwards. I mean, you're going to be washing
your suit out, but you know, if if you don't
(49:34):
thoroughly wash it out, you could get some some some
some urine odors, you know, in the material and so forth.
But and then again they stress that, yeah, you're gonna
get a warm burst, but it's not going to be lasting.
It's not. It's just just going to be a burst.
Speaker 3 (49:51):
You know, correct me if I'm wrong. But I bet
a lot of people don't own their own dive suits
to your kind of is it a rental situation?
Speaker 1 (49:58):
Yeah, yeah, I mean now that you mentioned it, like
the dive suit I urinated in was definitely not mine.
No shape was provided for me. And uh yeah, I
trust that they sprayed it out afterwards, I guess, so
it didn't seem gross when I put it on. So
uh And I imagine a lot of people have peede
(50:18):
in that suit.
Speaker 3 (50:19):
Sound like everybody does it. I'm sure they wash them
real good.
Speaker 1 (50:22):
I would love to hear from folks out there who've
done like a lot of like scuba and snorkeling in
wet suits. And you can add your own, you know,
two cents to this whole discussion.
Speaker 3 (50:36):
Well, Rob, this topic went places I did not expect,
but I have I have found great delight in the
twists and turns.
Speaker 1 (50:42):
Yeah yeah, yeah, As is often the case, once you
really get into a topic. You don't know where it's
going to take you.
Speaker 3 (50:49):
Hey, but if you're somebody who happens to see storks, vultures, condors, ganets,
boobies in the wild, uh, and you catch them with
with like seeing this taking place, let us know. Do
you have any picture what's going on?
Speaker 1 (51:01):
Yeah, that's right. We want natural world observations as well
as reports on adventures and paying yourself.
Speaker 3 (51:08):
Please no pictures of human just the.
Speaker 1 (51:11):
Birds, just the birds please, or the scenes. Yeah all right,
Well we're going to go and close out this episode,
but we'll remind you that Stuff to Blow Your Mind
is primarily a science and culture podcast, with core episodes
on Tuesdays and Thursdays and on Fridays. We set aside
most serious concerns to just talk about a weird film
on weird House Cinema, so you can always look out
(51:31):
for those episodes. You can find us on Instagram. We
are STBYM podcast.
Speaker 3 (51:35):
There huge things as always to our excellent audio producer
JJ Posway. If you would like to get in touch
with us with feedback on this episode or any other,
to suggest a topic for the future, or just to
say hello, you can email us at contact at Stuff
to Blow Your Mind dot com.
Speaker 2 (51:50):
Stuff to Blow Your Mind is production of iHeart Radio.
For more podcasts from iHeart Radio, visit the iHeartRadio app,
Apple Podcasts, or wherever you're listening to your favorite shows.
Hey, welcome to Stuff to Blow Your Mind. This is
a holiday week for us, so today we have another
vault episode for you. This is going to be a
case of the urine sweats. This is an episode that
originally published eleven, nineteen, twenty twenty four, and we're going
to get into the avian habit of urinating and or
(00:27):
defecating onto the scaly parts of one's own legs. Let's
find out all about it.
Speaker 2 (00:36):
Welcome to Stuff to Blow Your Mind, production of iHeartRadio.
Speaker 1 (00:46):
Hey you, welcome to Stuff to Blow your Mind. My
name is Robert.
Speaker 3 (00:49):
Lamb and I am Joe McCormick. And today on Stuff
to Blow Your Mind, we're going to be talking about
a concept called euro hydrosis. I'm not going to do
any see roundabout introduction. I think we owe it to
you to cut right to the chase, which is that
today we're going to be talking about the biological reasons
an animal might want to poop and pee all over itself. Yeah.
Speaker 1 (01:13):
Yeah, this is gonna be one of those episodes. So
if you're not in the right headspace for this discussion,
you know, come back and listen to the episode another time.
But I think most of you are probably on board
for this.
Speaker 3 (01:25):
So before we get to the reasons why, I think
we should start with just a kind of visual introduction
and observation, and it is that if you look at
some long legged birds strutting around in their natural habitat,
maybe wandering in the grass or on the rocks, foraging
for food or getting ready for mating, you will sometimes
(01:45):
see their legs covered in a pale residue. And Rob,
I'm attaching some images for you to look at here
in the outline, but people at home, you may want
to look these up for yourself when I give you
the names. So the examples I'm about to mention would
be three stork species. One is Seconia episcopus. This is
the wooly necked stork. Another one is Micteria leucocephala, which
(02:10):
is the painted stork, and another is Leptoptalus creminifer, the
marrabou stork. Now, these are all storks with long, thin legs,
I would say very roughly, you know, body length or
longer standing in an upright posture, and in the pictures
I've provided for you, Rob, these come from a paper
(02:32):
that we're going to talk about in just a minute,
you can see in patches that the legs and feet
have a natural pigmentation. They've got maybe a gray or
brown or black color on the skin of the legs
and feet. But in all three of these images, the
legs are mostly covered in some kind of white substance.
(02:52):
And if you had to guess what it is, what
would you think it is? Indeed, what you're probably thinking,
it's not.
Speaker 1 (03:00):
It's not some sort of a glittery bomb, right, it's not.
It's not any kind of as we've discussed, it's not
clothing that they're wearing here over their their long legs.
Speaker 3 (03:09):
It's something else, that's right. It is the bird's poop. Technically,
in mammal terms, you might want to say it is
both urine and feces, because birds deal with their excreta
in a kind of different way than mammals do. They
basically do it all in one go. It's not a
separate poop and p It's all one thing.
Speaker 1 (03:29):
Yes, the Glory of the Cloaca, which long time listeners
to Stuff to Blow your Mind have a fair amount
of familiarity with, though I don't think we've done an
episode on the kloaca recently. An old episode on the cloaca.
Speaker 3 (03:42):
Remember it's a classic from many years ago. I think
you and Julie did some cloaca.
Speaker 1 (03:47):
Yeah, yeah, and then it's come up, you know, it
comes up anytime we're potentially talking about reproduction and digestion,
when you know, concerning birds and other animals. Sometimes it
pops up in discussions of prehistoric cree as well.
Speaker 3 (04:01):
That's right. So with these animals, with the bird or
reptile lineage, you're going to be doing digestive waste, renal
system waste and reproduction is just all going in and
out the same hole, the kloaeca. So anyway, I got
interested in the concept of eurohydrosis, the idea that birds
would be intentionally having an adaptation to excrete waste all
(04:24):
over their own bodies, all over their own legs, and
so I was looking for scientific sources about this. So
I found a paper from twenty twenty one that lays
it all out pretty well. This is a paper in
the journal Scientific Reports, and I apologize if I pronounced
any of the author's names wrong. Here. It is by
Julian Kabeo Verguel, Andrea Soriano Redondo Auxiliadora Viegas Jose A.
(04:49):
Maseroje M. Sanchez Guzman and Jorge S. Gutierrez, and the
paper is called eurohydrosis as an overlooked cooling mechanism in
long legged birds. So basically all animals on Earth need
to regulate their internal body temperature, and there are a
lot of reasons for this. Of course, we're all basically
(05:10):
different types of water bags moving around and reproducing ourselves.
So at the extremes you need to manage yourself as
a water bag. You need to prevent your water content
from freezing solid or turning into steam. But beyond those extremes,
animals also need to keep their body temperature within a
fairly narrow range to protect cellular function and facilitate the
(05:32):
chemistry of metabolism, like there are certain enzymes in the
body that don't work right if they're outside of a
certain temperature range, and so forth. And there are broadly
two different ways that an animal species can be oriented
with respect to the regulation of body temperature. These are
ectothermy and endothermy. Endotherms also known as warm blooded animals
(05:53):
generate their own internal heat from metabolism, so they burn
food energy and use homeostatic mechanisms like shivering and sweating
and so forth to keep body temperature within a very
tight range. Mammals and birds are generally endotherms. They primarily
regulate their temperature with internal mechanisms. Ectotherms, on the other hand,
(06:16):
sometimes called cold blooded animals, regulate their body temperature mostly
with the help of the outside environment. So these are
the animals that you would think of as sun basking
or cooling in water in order to manage their body temperature.
Ectothermic animals include most reptiles, amphibians, and fish. Though to
be clear, the cut between ectothermy and endothermy is not
(06:39):
a clean cut. There are a lot of kind of
blurry cases in between, just sort of a generally helpful distinction. Now,
there are advantages to each of these major strategies. We
could come back and go deep on this someday, and
we've talked about it somewhat in the past, I believe,
But a very simplified version is that indotherms animals that
primarily rate their own heat through metabolism, they can do
(07:03):
a lot more. They can sustain more muscular activity, they
can grow more powerful brains, they can survive in a
greater range of different climates, you know you don't usually
see like reptiles and extremely cold climates and so forth.
But they also require a lot more food. Ectotherms are
efficient because they don't leave the motor running all the time.
(07:25):
They can usually go much longer in between meals and
can survive rough patches by kind of going dormant. Now,
because this paper is focused on birds, we're in the
domain of the indotherms, the warm blooded animals that primarily
generate heat through their own internal metabolic mechanisms. But even
endotherms can't regulate everything internally, and the authors begin the
(07:49):
paper by discussing various ways that endothermic animals do still
have to protect themselves from external heat stress, from getting
too hot because the environment is too hot. And some
of these defense mechanisms against overheating are physiological and some
are what you'd probably call behavioral, and the authors say
(08:10):
that typically the first response, the first priority response, in
the responses you go through when you're encountering heat stress
is behavioral, and this could involve the selection of cooler microclimates,
going to cooler places from warmer places, or what they
call heat dissipating behaviors, And there are many different kinds
(08:31):
of heat dissipating behaviors in nature. This could mean something
as simple and as familiar to us as reducing physical activity.
You know, it's hot out, you stop moving around so much,
or moving out of the sun and into the shade,
or things like getting in the water for a swim.
Being submerged, even in what feels like fairly warm water,
(08:52):
actually removes heat from the body quite efficiently. The author
is mentioned later in the paper that the thermal conductivity of
water is twenty five times that of air. So you're
you might have had this experience before where you know,
even in a pool that doesn't feel very cold, the
water feels nice and warm. You spend too long in
the pool, you really will start to chill out and
(09:15):
you need to get out of the water and warm up.
Speaker 1 (09:17):
Yeah, so you can basically could basically like roleplay all
of these like you almost have like an innate pull
towards these various thermoregulation options. You know, if we were
to position you, say, you know, a nice pool patio
on a hot summer day, what are some of your options?
You know, do you choose the umbrella, do you choose
the pool, do you choose the shade of the house
(09:38):
and so forth.
Speaker 3 (09:39):
That's right. And then there's another class of heat dissipating
behaviors which could be called like posteral adjustments, and this
could be just positioning the body in different ways to
maximize how much heat it is getting rid of. One
example is spreading out the body tissues to increase your
surface area. So think about how when you're cold, you
(09:59):
kind of try to s shrink down, don't you. You
try to shrink your body into a ball and reduce
your surface area. You might hug your arms into yourself
and kind of kind of crouch. But in the heat,
if you're overheating, you don't want your legs touching each other,
and you don't want your arms touching your body. You
want to splay out maximally to have maximal surface area,
which means heat can escape your body with the greatest efficiency.
Speaker 1 (10:22):
Or you might want to fan out your neural spine
sale for a yes, or if you want to regulate
your temperature that way. If you have a neural spine sale,
I'm not going to presume everyone has one.
Speaker 3 (10:32):
Or if you're a bird, you might want to fold
unfold your wings, hold your wings out to let you
know heat radiate that way. You know, different animals exactly
the spine sales. This is a great example. You know,
different animals have different ways of increasing their surface area
and radiating more heat. Now, if the endothermic animal cannot
escape heat stress with just the behavioral responses, it has
(10:54):
to switch gears into what the authors call rapid physiological adjustments.
This is things that the body does we would usually
think of as involuntarily to try to remove heat faster.
And these can vary across different types of animals, but
it could include things like in humans, sweating, in other animals,
(11:14):
panting or increasing the breathing rate to dissipate more heat
from the lungs and the respiratory system. Now, the authors
point out that in birds, one of the most common
physiological mechanisms for removing heat is what they call panting.
I've seen some sources reject that terminology, maybe because they
(11:34):
think it incorrectly implies it's the exact same thing that
dogs do, But it's similar either way. For birds, panting
involves rapid breathing with an open mouth. They might hold
the bill open and breathe in and out very rapidly
to purge heat through evaporation from the warm, moist tissues
inside the mouth, throat, and lungs. This is also sometimes
(11:56):
accompanied by another response called gooler fluttering u laar fluttering,
which means like they would, the bird will vigorously vibrate
the muscles and membranes inside its throat while panting to
further increase evaporation and the purging of heat. Now, these
physiological adjustments, they do work. They will purge heat from
(12:18):
the body and help avoid hyperthermia, help the animal cool down,
but they're also very costly. They're costly and thus risky
to the animal because they can waste important resources like
energy and water. Birds can lose a lot of water
through panting and fluttering, and in addition, the authors mentioned
(12:39):
that panting in birds can force potentially undesirable changes in
blood chemistry. So, if you're an animal in the wild
fighting for survival, you know you have these physiological mechanisms,
these sort of rapid body adjustments that you can rely
on if you have to, but you would like to
avoid them. You would like to avoid going into these
(13:00):
wasteful physiological protections against heat if you can help it,
and the more efficient behavioral methods should be your first
line of defense. So for a human analogy, it's usually
it's going to be less costly to your body to
just get into the shade and get out of the
heat than it is to start sweating bullets. In their introduction,
the authors of this paper introduce a concept from zoology
(13:22):
called heat dissipation limit theory, which argues that in indotherms,
the problem of how to deal with excess heat produced
by metabolism limits how much energy you can take in
and by consequence, limits reproductive output. So the author is
right that under this theory, heat dissipation behaviors could really
(13:43):
be crucial to the evolutionary success of a species because
they allow more chemical energy to be devoted to foraging
and reproduction and things like that, rather than to physiological
mechanisms simply for getting excess heat out of the body.
And the author is mentioned that the sort of research
context of this paper is that thermoregulatory behaviors and animals
(14:05):
are increasingly being studied because of the current and future
increases in heat stress on wildlife due to global warming,
where the ability of an animal species to deal with
heat stress without resorting to costly physiological mechanisms may be
the difference between adaptation and extinction, So this is something
that is probably just going to get more and more
(14:26):
attention from people who study wildlife, especially as the heat
stresses of environments are changing more rapidly. Now, another interesting
fact about how birds protect themselves against overheating has to
(14:49):
do with what the authors call quote unfeathered and well
vascularized appendages, meaning parts of the body that are bare
so not covered in feathers, and parts of the body
containing a lot of blood vessels. And examples here would
be the bill, the bird's bill around the mouth, and
the legs. Because these parts of the body are typically
(15:10):
not insulated by feathers and lots of blood flows through them,
and for these two reasons, these parts of the body
can be utilized pretty well as what the authors call
thermal radiators to purge excess heat, and this is especially
the case for storks. The storks belong to the in
scientific classification, they belong to the family Sickniady, which storks
(15:35):
typically have long, bare legs and most often live in
warm or hot climates with little shade. So storks have
an internal mechanism for making use of these thermal radiators
in the body for making use of the long legs
for temperature management. Storks can actually alter the blood flow
(15:56):
to their legs, constricting the blood vessels down the when
it's cold out so less blood is flowing through and
there's less heat exchange, and then dilating the blood vessels
in the legs when it's hot, promoting more heat loss
from the body down in the legs. But in the
case of storks, the use of the legs as thermal
radiators goes one step further, and here's where we get
(16:17):
back to the topic for today. Eurohydrosis the author's right quote. Notably,
storks can deliberately excrete onto their legs when exposed to
increasing environmental temperatures, a phenomenon known as eurohydrosis. When overheated,
storks repeatedly direct liquid xcrita toward their legs, only one
(16:39):
leg at a time, which usually evaporates before reaching the toes.
So it's hard to imagine this from a human perspective,
but the more you think about it, the more it
does make biological sense. Imagine you're out in the sun
on a blazing summer day. The heat's really getting to you.
You have a few options to cope. You could stop
moving around and fly down in a chair. You could
(17:01):
get out of the sun and into the shade. You
could hop into a pool. Or if those options are
not really available to you at the moment, you could
poop all over your own legs, one leg at a time,
and then hope that that helps cool you off.
Speaker 1 (17:15):
Granted, there are certain consistency challenges here. Yes, yes, some
dietary adjustments might be necessary in order to ensure this
as a viable tactic for human beings. But I think
we all have great imaginations we can see it.
Speaker 3 (17:30):
I'm not recommending this as a tactic for human beings.
I don't know that this would work for a human.
It might be a bad trade off. But it works
for the storks. But the question is how does it
work for the stork? How does it cool the body? Well,
it is actually the same physical principle at work as
many other thermoregulation techniques in nature. It is evaporative cooling.
(17:51):
We've talked about evaporative cooling and a number of contexts
on the show before. I think we did an invention
series on the history of air conditioning. The air conditioning
where we talked a lot about evaporative cooling, and it's
come up in a biological context as well. But the
short version is that the phase transition from liquid water
into water vapor requires a lot of heat energy to
(18:14):
take place. So water that is evaporating into the air
cools down very rapidly and in turn cools whatever it
is touching, such as your body if it's on the
surface of your skin. And if you ever want to
do a simple experiment in your home to see evaporative
cooling at work, you can try. This is kind of fun.
You can get two bottles of water at the same
(18:36):
temperature room temperature bottles of water, and you put them
both in front of a fan, and now one you
just sit there with nothing, you know, by itself, but
the other one wrap the bottle in a wet towel,
set them both in front of the fan, and then
come back in like half an hour. The regular bottle
will not have cooled off significantly, but the bottle that
(18:56):
you wrapped in a wet towel will be very cold
because as airflow from the fan causes the water in
the wet towel to quickly evaporate, it will suck heat
from the water in the bottle and make it cold.
I think this is an old trick that like people
traveling in desert climates, you know, without artificial cooling used
to use where they would, you know, they'd have like
(19:18):
a big jug of water, like a big skin of water,
and to keep it cool as they're traveling in the
hot desert sun, they would also get like a cloth
and wet it at the beginning of the day and
wrap it around the outside of this skin of water.
And as the water evaporates from the hot cloth on
the outside through the day under the hot sun, it
sucks heat from the water inside and makes the water
(19:39):
very cold. And evaporative cooling is why sweating cools the body.
You know, as sweat evaporates from your skin, it steals
heat energy from your body and it cools you off. Now,
of course, sweating has a downside, which is that it
causes you to lose water and electrolytes. So when you're
hot and sweaty, it's very important to keep hydrated to
(20:01):
compensate for the water loss. Exercising in the hot sun
one oh one, you got to drink lots of fluids.
The same is true for birds. Now, birds don't sweat,
they don't have sweat glands, they can't sweat, but they
do have their own evaporative cooling techniques, and as we
talked about, the panting is one of those techniques where
they can use evaporative cooling in their respiratory system with
(20:23):
the open bill rapid breathing, and eurohydrosis is one of
these techniques. The author's right that eurohydrosis is relatively rare
among birds because it requires ready access to a lot
of drinking water, but plenty of bird groups have been
observed to do it. They list New World vultures, storks, condors, gannets,
(20:46):
and boobies. And eurohodrosis has been known about for a
long time, but the authors say there still has been
relatively little investigation of what exactly are the environmental and
physiological factors that determine it, like what causes one bird
group to use eurohedrosis and another group do not use it.
(21:08):
So the authors came up with a systematic way of
looking into this. Now, this particular study relied on essentially
repositories of scientific media, like imagery of birds from various
field locations that was associated with metadata, so that you
could try to correlate like images of birds doing certain
(21:28):
things and the environmental data about them. So this was
not direct field test with variables that the authors could manipulate,
but they were just trying to establish correlations between like
environmental factors and factors about the bird's bodies, along with
observations of do these birds poop on their own legs
(21:48):
or not? So what environmental factors did they find correlating
with the use of eurohydrosis by storks? The authors found
that high temperatures, high solar radiation in higher air humidity,
and low wind speed were all factors that would increase
the baseline heat stress risk for an endothermic animal, and
(22:11):
storks in environments with all of these conditions were more
likely to engage in eurohydrosis. They also found that it
was more common among stork species that forage on dry
land as opposed to those that commonly inhabit water bodies
and forage by wading, which kind of makes sense to me, Like,
if you can get your legs wet without pooping on them,
(22:32):
all the better, right, But some storks are not in
a position to spend as much time hanging out in
the water.
Speaker 1 (22:39):
Right right, Or you're dealing with water that's very shallow. Yeah,
you know, we've all seen storks in the wild, I think,
and yeah, yeah, sometimes they're in very shallow waters.
Speaker 3 (22:49):
Now, even storks that sometimes wide in water do apparently
use eurohydrosis, just less often. For these species. It may
be more limited to times when circums stances create a
higher heat risk, such as during reproduction when they need
to be out of the water in the heat for
extended time. But anyway, the authors say that the hypothesis
(23:09):
that eurohydrosis correlates to open and warm habitats was confirmed.
Birds that sort of live out in the open in
hot places, they're the ones that are going to be
more likely to do this to help cool their bodies. Now,
there were some other hypotheses that had been put forward
by these authors and other authors that were not confirmed
in this research. It had been hypothesized that stork pigmentation
(23:34):
would be correlated to the use of eurohydrosis. The ideas
maybe that birds with darker pigmentation absorbed more heat from
the sun, but this was not supported by the survey.
They did not find that correlation. It had also been
hypothesized that eurohydrosis would directly correlate to the latitude where
birds live, with tropical species practicing it more. This was
(23:57):
also not strictly supported, though again there's some complications because
some of these birds, you know, they will travel, live
at different latitudes different parts of the year, and again warmer,
more open environments did predict it, it was just not
strictly latitude. Another thing that was not supported was a
hypothesis about body mass. This was something that the authors
(24:19):
of this paper predicted. They thought that higher body mass
would predict more eurohydrosis because the animal would have more
water reserves to take advantage of, Like if you're you know,
you're a bigger animal, you can drink more water, store
more water in the body. You can also you've got
more to you know, to waste in pooping on your
own legs to cool off. But this was actually not
(24:41):
the case. This might have to do with the fact
that these storks all had access to water bodies for
regular drinking, even if they didn't spend a lot of
their time waiting around in that water, so maybe internal
water stores were less of a concern. Looking beyond storks,
the authors note that even other bird gre groups that
practice heurohydrosis, like New World vultures, boobies, and gannets. They
(25:05):
all tend to breed or forage in hot, open land
areas under the sun, and they also tend to have
relatively large and highly vascularized legs, so there seem to
be some common environmental and physiological pressures at work. Now,
some other interesting observations from their conclusion I thought one
was that when comparing different ways of cooling the body
(25:28):
at the cost of energy and water reserves, the authors
conclude that eurohydrosis is actually cheaper than panting, which was
kind of surprising to me that that was counterintuitive, but
they said this is supported by the fact that birds
who have the adaptation tend to engage in leg pooping
at a lower temperature threshold than the temperature threshold for panting.
(25:51):
So I think kind of like how if you're a human,
humans will typically resort to like changing into short sleeves
before they will resort to like jumping into ice water bath.
You know, one is like a more severe costly activity
than the other, And it seems like for these birds,
panting is the more severe, more costly, and risky activity.
(26:12):
The authors also note that other animals, apart from birds,
use alternative evaporative cooling methods, not just not just sweating
like we do. They say some mammals produce excess saliva
when hot and then use evaporative cooling through the mouth
or even cool the body by like drooling or licking
on themselves on the outside and then allowing that saliva
(26:33):
to evaporate. Rob I know, you've got an alternative evaporative
cooling method to talk about in a minute. But they
end up saying that there could be some tradeoffs involved here.
There's possibly that this is not a strong not something
they strongly established, but a possibility is that there could
be a tradeoff between mate signaling based on the pigmentation
(26:56):
of bird legs and the cooling benefits of eurohydrosis. But
this is yet to be fully explored. But the idea
here would be if this were the case, that it
helps you advertise mating fitness better, if like the correct
pigmentation on your legs is showing, and that by pooping
all over your legs, this like changes the way you
look and sort of downgrades your mating appeal. So there
(27:19):
could be some push and pull there, but that wasn't
very well established. But more briefly, I did want to
mention a second paper that involved three of the same
authors as the previous paper, because it had some interesting
follow up on this and involved a more direct method.
And so the second paper was by again three of
the same authors, Kubeovergel, Viegas and Gutierrez, and this one
(27:44):
was called Keeping Cool with Poop. Eurohydrosis lowers leg surface
temperature by up to six degrees celsius in breeding white storks,
published in Ecosphere in twenty twenty three. And this study
was a direct attempt to measure that the magnitude and
dear duration of the evaporative cooling that you get from
eurohydrosis in free ranging birds. The study used observations of
(28:08):
eurohydrosis in white storks or Seconias econia, paired with thermal
imaging and microclimate measurements to see like exactly how much
benefit the leg pooping was providing. Now, this next part
in the abstract did make me laugh. They write, quote,
we show that eurohydrosis can reduce leg surface temperature by
(28:29):
up to six point seven degrees celsius, which is actually
four point four plus or minus one point zero four
degrees celsius. Yet its cooling effect was of short duration,
lasting no more than two point five minutes and decreased
with time since defecation. Which actually that makes sense, right,
because like, if you're trying to work through evaporative cooling,
(28:51):
as the bird poops on its leg, it will be
very it will have a great cooling effect while the
poop is still very wet, but then as it evaporates,
it will dry up, and then it will provide less
of a cooling benefit and may even have some negative
effect in fact, if it like cakes on.
Speaker 1 (29:07):
You know, let's keep all of this in mind as
we perceive, right.
Speaker 3 (29:12):
So, but then there's the second second thing here. The
selection continues quote. Thus, for eurohydrosis to significantly contribute to
heat dissipation, storks must perform it repeatedly when overheated. So
the leg pooping must go on and on, and it
turns out it does. The authors found that the white
storks here can poop on themselves eleven times per hour.
(29:36):
And I did a little math there. So with like
two point five minutes of cooling with each blast, that's
twenty seven point five minutes of cooling per hour. If
they do it eleven times, almost half of the time
of the hour is in cooling. Mode. So the authors
estimate that eurohydrosis can cover quote four percent of the
daily field metabolic rate for an adult stork. Wow.
Speaker 1 (29:59):
So it's like any like cooling system in a house
that might it might not be on all the time.
That would probably be just biologically impossible, but it's going
to keep coming on periodically to try and keep the
temperature down.
Speaker 3 (30:11):
Yeah, that's a great comparison. It'll trigger repeatedly over time
to kick off little short periods of cooling, and then
the body temperature will come back up again, and then
the bird will release the excreta again and it will
set off another short period of cooling, and it'll go
back and forth. Now, I just did want to I
mentioned this on the earlier study, but I did want
(30:32):
to emphasize again. Unless you think, oh, you know, this
is just silly, this is actually interesting and relevant knowledge,
and will things like this will be of increasing importance
to wildlife and conservation biologists over time. The author's right quote.
Gaining knowledge about behavioral thermoregulation in the heat is therefore
crucial to better predict the future persistence and vulnerability of
(30:55):
species under different climate warming scenarios. A lot of these
species are going to be living in places where the
local climate is increasing in heat over time. That's increasing
the heat stress on animals that live in the wild,
and some animals will be better or worse able to
deal with it than others. There was another question that
(31:24):
came out because I saw some stuff online in discussions
about eurohidrosis that was about possible other functions. It seems
pretty clear that certainly in storks, it's playing a role
in cooling the body. But is eurohidrosis just to cool
the body or in some species, could it be playing
(31:45):
another role as well? Like I saw some ideas that
it could possibly have an antibacterial function.
Speaker 1 (31:51):
Yeah, and that brings us back to the gross and
wonderful world of vultures. These splendid kings and queens who
keep our s it's clear of carcasses and in general
are just great decomposers there. There were a few in
our neighborhood not to just a week or so ago.
They were disrupting traffic. But you know, as we went
(32:12):
by them, we saluted them because they were they were
doing the lord's work out there.
Speaker 3 (32:16):
They're worthy of our respect. Yes.
Speaker 1 (32:18):
So, yeah, there's this idea that various New World vultures
are engaging in this kind of you know, possible euro hydrosis,
but maybe not for temperature control purposes. That you know,
they've been observed to do it when it's cold, they've
been observed to do it when it's warm, So what
could the purpose be. And there is this idea that
(32:39):
it is essentially kind of like when we reach for
a container of a hand sanitizer, except for the vulture whose,
of course, you know, it's it's getting its talons into
various you know, grotesque feasts there on the side of
the road or in the wilderness and so forth. Occasionally
it makes sense to to sam ties those legs with
(33:01):
an eye, perhaps with a nice you know, coloacal wash.
And so that is the theory that there is an
antiseptic nature of vulture defecation and that it, you know,
especially would be important for various scrapes and cuts on
those appendages. And so I was reading about this in
a twenty twenty two book, Vultures of the World, in
(33:22):
which the author Keith l builds and points out that
at the time, at any rate, the antiseptic nature of
vulture defication had not been like tested to the fullest.
So it's still kind of an open question, but this
does seem to be a strong argument, again based in
large part of the fact that they do seem to
(33:43):
do it both in summer and winter, suggesting that disinfection
might be at least an important part of the equation
for like turkey vultures. Okay, now, an interesting fact about this.
I was not familiar with this, but the author here
points out that in US, in US and Canada at
any rate, vulture researchers are prohibited from using leg bands
(34:05):
on turkey vultures because there's a risk of uric acid
building up and cementing around the leg band, because again
they're pooping and peeing down those legs. If you have
a band there for tracking purposes, it could you know,
it gets caught there, it drives there, it's cements there,
and this could effectively hobble the bird over time. Eventually
(34:27):
it's like too big of a weight for them to
fly off with apparently, or at least you know, it
would get in the way of their they're flying, in
their ability to carry out their daily activities. So fortunately,
there are other methods for tracking them, things like wing
tags and the like. But putting a leg tag on
them as a no no. Now, before we get away
(34:48):
from birds, I do want to point out that in looking,
I'm always interested to see if there's any kind of
mythological or folklooric tie in to a particular topic, And
I really wasn't expecting much here, but I did find
mention of this in connection to Amazonian mythology via a
book titled an Amazonian myth and its History by Peter
(35:11):
Goal that came out in two thousand and one. So
the story involved here is referred to as the Sun,
and it entails a character who is at one point eviscerated,
but in a nice way, like in a like a
polite mythic way, like he's asleep, and the creatures that
(35:32):
are working for him like remove his intestines. But at
any rate, the story involves a character who's eviscerated becomes gutless,
and by becoming gutless, can now eat and drink all
he wants, but can also never be satisfied. And this
is a story that Gal says is apparently connected to
observations of the wood stork who appeared gutless because they
(35:56):
are constantly excreting waste. You mentioned like how often per
hour they are excreting in order to cool those legs down,
and it can lead to this observation it's like, well,
this animal poops all the time, and we don't do that,
like we you know, we know exactly, we know more
or less what's happening when we consume food and it
becomes nourishment and so forth. Perhaps the stork is not
(36:18):
giving it time at all, is just going straight through.
And therefore, you know, there's just these kind of you know,
ravenous but unsatisfied creatures.
Speaker 3 (36:28):
Interesting. Now, I didn't come across a poop count on
the wood stork, but in that one study, yet there
was the white stork, and it was up to eleven
times per hour. Wow, that's a lot.
Speaker 1 (36:39):
So the myth, as recounted, apparently involves a man who
has enslaved the wood storks to do his bidding, but
then while he's asleep in the canoe, they remove his intestines,
and they intestines and they like hang them over the
side of the canoe, and when he wakes up, he's like, hey,
what's this stuff here? They have carently don't say anything,
(37:00):
so he throws it out and then the storks tell
him later they're like, oh, yeah, by the way, those
we are intestines. So as I understand that what we
have here is we have an observation of nature, an
incorrect hypothesis or a very loose hypothesis that may be
concerned more with the mythic purposes of the tail as
opposed to anything else. And then this bleeds into an
(37:24):
anatomical mythology that presents something almost like a hungry ghost,
you know, this idea of a being that cannot be
satisfied because his digestive capabilities are just not intact, and
that perhaps that's what we see when we see these
storks as well.
Speaker 3 (37:44):
Interesting. I mean, I guess that does sort of tie
into the observation that the storks most likely to engage
in this are the ones that are going to be
out in the sun on dry land in the heat,
but also birds that have ready access to drinking water,
and that this would probably not be a good adaptation
for a bird species that had to, you know, that
(38:04):
had to conserve water resources maximally and did not have
ready access to water bodies. Yeah.
Speaker 1 (38:10):
Yeah, I didn't have enough time to really dive into
this text, but it's out there. If anyone else wants
to look into it again. The author is Peter gow
who lived nineteen fifty eight through twenty twenty one. He
was a social anthropologist who worked a lot in the Amazon.
Speaker 3 (38:26):
Interesting story, Yeah, yeah, I also was. I did not
think there would be a eurohydrosis related myth.
Speaker 1 (38:33):
Oh, but here we are. Let's see other animals. Though,
interestingly enough, we also see this in some aquatic mammals.
The main example that I was reading about in a
paper that you sent to me, Joe, is the southern
fur seal or arctocephalus. This is this means bare head
(38:55):
because we're talking about Antarctic fur seals here. These are
furry looking critters adapted to thrive in very cold waters. However,
as Roger L. Gentry discusses in the nineteen seventy three
paper thermo Regulatory Behavior of Eared Seals, this published in
the journal Behavior, they have other means of thermoregulation that
(39:16):
become necessary when these well insulated creatures are out of
the water and caring about on the shore, on the
rocks in the sun.
Speaker 3 (39:25):
Ah Okay, so this might be a different situation than
the storks living in like a really hot climate under
the direct sun. I mean, I guess you could still
have the sun beating down on you. But the issue
here would be that the seals are very well adapted
to the cold, and so in cases where they're under
the sun and it's not very cold, their heat conserving
adaptations are working against them.
Speaker 1 (39:48):
Right And the situation where this becomes essential, especially for
the males, it has to do with their breeding period,
because they live a lot of their lives in the water,
but they they come on to land, you know, during
the breeding period, and it's very important for a male
to hold down his territory. So there's a lot of
(40:09):
fighting and squabbling for territory and for females, and it's
a it can be a real endurance game for the
males of you know, various seal species species because they're
having to constantly fight and at the same time they
have to maintain acceptable body temperatures, they have to thermoregulate,
and they're not in the water at this point. The
(40:30):
water is the author points out, the ideal place for
this creature to cool down. But you're fighting a territory war,
in a mating war up here on the rocks. So
getting back in the water is something you can do,
but that is going to be like your last resort
because you're giving up territory at that point, so you
(40:52):
have to do other things. So Jenry discusses how, especially
during the high temperatures in these environments, you'll see a
few different behaviors. So on one hand, they will seek
out shade or shade cooled rocks, which you know, kind
of the same thing. But it's essential to note that
rocks of course heat up in the sun, so being
in the shade is one level of protection, but also
(41:15):
being on rocks that are either currently or have just
previously been cooled by the shade is also worth thinking about.
And so according to Gentry, during higher temperatures, these seals
have been observed to stand on all fours and then
annoy their flippers and bellies with urine, with the back
of flippers being the key, because then they'll lay on
(41:38):
one side and extend their now wet rear flipper into
the air, and this will be the way they carry
carry out some evaporative cooling. He also notes that the
males seemingly drink more water in the surf during this
time period in order to provide more urine for thermoregulation
when they're out on the shore. So, coming back to
(41:59):
what we were talking about with the with the storks,
if you're going to engage in something like this, you've
got to keep you got to keep the fluids flowing.
Speaker 3 (42:07):
That is so interesting imagining like the sort of the
chain of preparations there I'm thinking about, So the male
seals like tanking up with water to get ready for
one of these one of these like breeding season things
where he knows he's going to be out under the sun.
Speaker 1 (42:21):
Now, this is also interesting to think about for me
because I did get to see Galapago's fur seals carrying
out carrying out their their various activities on the beach
when I was down at the Galapagos Islands, and I
didn't even know to look out for any kind of
urination going on.
Speaker 3 (42:38):
I did.
Speaker 1 (42:39):
I don't think I saw any like actual throwdowns between
male seals, but I did get to see like some
of what they're up to. So yeah, I wish i'd
known to look out for this.
Speaker 3 (42:51):
What does it look what does it look like some
we're just trying to like stake out good territory.
Speaker 1 (42:55):
Yeah, you'll see like a big male and a bunch
of females and then you know, basically trying to hold
down the territory of this part of the beach with
these females. And then occasionally here's some other male seal
coming that is going to contest this situation, and then
you know, there are various little squabbles about where the
females are getting to lay about as well. And then
(43:18):
you know, sometimes and then this is also inevitably happening
or a lot of the time, it's happening on beaches
that where people are also hanging around, so they're also
human tourists, so there's a lot of and of course
when the seals decide they want to go somewhere, it's
like it's time for the humans to move.
Speaker 3 (43:36):
Don't mess with seals, folks.
Speaker 1 (43:37):
Yeah, but sometimes they could be a little like at
one point, I was just sitting there with my family
and there was like a smaller, very loud female seal
and she just decided she needed to set where I was,
So of course I moved and then she sat there
for a little bit and kind of you know, catterwaulled
a bit, and then she moved on elsewhere. But it
was like I don't know. It kind of felt like
(43:57):
she was being a little petty, but this beach belongs
to you. I'm just visiting, very magnanimous. Yes, hey, just
a quick post publication note. I want to insert here
Everything that I was saying about the fur seals is
correct according to my research. But in the heat of
(44:18):
the moment, I mentioned the Galapagos, and I mistook my
memory of Galapagos Sea lions for Galapago's fur seals. So
sorry about that. My apologies, but I did want to
throw in this post publication correction here for anyone who
listens to the episode later. Yeah, I didn't have anything
(44:41):
about the Galapagos in my notes. It's just as I
was going through this part of the episode, it stirred
a memory, and as is sometimes the case with memories
that are recalled from the depths, sometimes it comes up
with a little bit of incorrect information applied there. So,
without further ado, let's get back into the episode. Now,
(45:01):
speaking of the Galapagos, this does bring me to the
next question that I had, because when I was in
the Glapagos, I did just a little bit of snorkeling
in very cold waters, and I was wearing a dive
suit because it gets cold. And if you've ever gone
diving or done scuba diving or snorkeling and you've worn
(45:23):
a wet suit and the water's been cold, you might
have done what a lot of people have done what
I did as well, and that is urinate in the
suit while you're in the water to warm things up
a bit. This instantly came to my mind when we
started getting into this, because, yeah, like this seems like
an example where humans can get in on the euro
hydrosis action, right, sort of in the opposite direction, in
(45:47):
the opposite direction, right, you know, can we just pee
in our dive suits in order to warm things up?
And you know, I was able to find a full
article about this on dive si dot com. That's Scuba
School's International.
Speaker 3 (46:04):
That's beautiful. Well what's the word? All right?
Speaker 1 (46:07):
So yeah, I didn't know what the what the full
scoop on this was. And I'm not like a big
I'm not a scuba diver and i am not a
wetsuit person, so I didn't even know what the accepted
wisdom was here. But the authors of this article point
out that, yeah, this is kind of like common lore
among divers and historically to scuba divers that that if
(46:27):
you get in a little cold, will pee in your
suit and then'll warm things up a bit. And they
point out that due to the mammalian dive response you
might need, you might have a heightened need to urinate
in this environment because a submerged mammal is going to
experience a slowed heart rate during free diving, especially, it's
going to narrow blood vessels and the extremities, and blood's
(46:48):
going to shift to the core parts of the body,
all in order to conserve oxygen and maintain blood flow
while holding one's breath. But more blood ends up going
to the core and then via the kidneys. This increase
the urge to urinate. So you might find yourself in
a situation where you're like, Wow, I just got into
the water off the boat, it's cold, I need a
(47:08):
pee anyway, Why don't we warm things up a bit?
And so yeah, they point out that this is a
common bit of diver's lore, and the article states quote
the wet suit itself works by trapping a thin layer
of water between the neoprene that's a synthetic rubber and
the skin, which the body warms. This layer serves as insulation,
(47:28):
keeping the diver warm in cold water. When a diver
urinates in their wet suit, the initial warm sensation comes
from the body warmed urine. However, this effect is fleeting.
Speaker 3 (47:39):
Nothing gold can stay.
Speaker 1 (47:41):
I mean in this we do kind of come back
to the situation with the storks, right, I mean that too,
is fleeting. Is a cooling burst that will have to
be reapplied. I think the problem with divers is that
you probably don't have that many goes at it here, right,
you probably? Oh? I mean, how many times can we
you urinate in your suit on a given dive or snorkel.
(48:05):
I could be wrong, but I have a feeling knowing
my body that truly it's just one, maybe two, but
not enough to not not eleven times per hour.
Speaker 3 (48:15):
Yeah, And if I'm understanding the dynamics here correctly, it
even then, like it's still just a sensation of warming.
Your body is not actually getting warmer from this, Like
you're you're losing warmth by peeing, But it's it feels
warm on the outside.
Speaker 1 (48:32):
Right, You're gonna get that. And I can testify to this. Yeah,
you get you get a warming sensation, but it is fleeting,
they point out, because the urine quickly cools and things
that will then actually feel colder when this cooling occurs.
You know, it's it's kind of like when you first
get into the cold water to swim about. It's like
it can be shocking, takes your breath away, but then
(48:52):
you get used to it and you carry on. When
you when you pee your suit in order to warm up,
you kind of like recreate something like that scenario again.
We're like, oh, now now it's cold again. Because and
part of this is the wet suit is not waterproof,
it's permeable, so outside cold water will directly cool the
layer of spreading warm urine in the suit. Now, all
(49:13):
that being said, the article stresses that ping in your
wet suit is a common practice, and it is it's
not harmful. You know, you may have some hygienic or
some comfort concerns about it, but basically all they really
advise on this is, look, if you do it, fine,
but just you want to make sure you wash out
your suit afterwards. I mean, you're going to be washing
your suit out, but you know, if if you don't
(49:34):
thoroughly wash it out, you could get some some some
some urine odors, you know, in the material and so forth.
But and then again they stress that, yeah, you're gonna
get a warm burst, but it's not going to be lasting.
It's not. It's just just going to be a burst.
Speaker 3 (49:51):
You know, correct me if I'm wrong. But I bet
a lot of people don't own their own dive suits
to your kind of is it a rental situation?
Speaker 1 (49:58):
Yeah, yeah, I mean now that you mentioned it, like
the dive suit I urinated in was definitely not mine.
No shape was provided for me. And uh yeah, I
trust that they sprayed it out afterwards, I guess, so
it didn't seem gross when I put it on. So
uh And I imagine a lot of people have peede
(50:18):
in that suit.
Speaker 3 (50:19):
Sound like everybody does it. I'm sure they wash them
real good.
Speaker 1 (50:22):
I would love to hear from folks out there who've
done like a lot of like scuba and snorkeling in
wet suits. And you can add your own, you know,
two cents to this whole discussion.
Speaker 3 (50:36):
Well, Rob, this topic went places I did not expect,
but I have I have found great delight in the
twists and turns.
Speaker 1 (50:42):
Yeah yeah, yeah, As is often the case, once you
really get into a topic. You don't know where it's
going to take you.
Speaker 3 (50:49):
Hey, but if you're somebody who happens to see storks, vultures, condors, ganets,
boobies in the wild, uh, and you catch them with
with like seeing this taking place, let us know. Do
you have any picture what's going on?
Speaker 1 (51:01):
Yeah, that's right. We want natural world observations as well
as reports on adventures and paying yourself.
Speaker 3 (51:08):
Please no pictures of human just the.
Speaker 1 (51:11):
Birds, just the birds please, or the scenes. Yeah all right,
Well we're going to go and close out this episode,
but we'll remind you that Stuff to Blow Your Mind
is primarily a science and culture podcast, with core episodes
on Tuesdays and Thursdays and on Fridays. We set aside
most serious concerns to just talk about a weird film
on weird House Cinema, so you can always look out
(51:31):
for those episodes. You can find us on Instagram. We
are STBYM podcast.
Speaker 3 (51:35):
There huge things as always to our excellent audio producer
JJ Posway. If you would like to get in touch
with us with feedback on this episode or any other,
to suggest a topic for the future, or just to
say hello, you can email us at contact at Stuff
to Blow Your Mind dot com.
Speaker 2 (51:50):
Stuff to Blow Your Mind is production of iHeart Radio.
For more podcasts from iHeart Radio, visit the iHeartRadio app,
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