November 19, 2024 • 51 mins
In this 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…
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Speaker 1 (00:03):
Welcome to Stuff to Blow Your Mind, the production of iHeartRadio.
Speaker 2 (00:12):
Hey you welcome to Stuff to Blow your Mind. My
name is Robert Lamb.
Speaker 3 (00:16):
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
fancy 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.
Speaker 4 (00:39):
Yeah.
Speaker 2 (00:39):
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 (00:51):
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
(01:11):
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 lucocephala, which
(01:37):
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
(01:59):
that we're going to talk about just a minute. You
can see in patches that the legs and feet have
a natural pigmentation.
Speaker 4 (02:06):
They've got maybe a.
Speaker 3 (02:07):
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.
And if you had to guess what it is, what
would you think it is? Indeed, what you're probably.
Speaker 2 (02:23):
Thinking, it's not some sort of a glittery bomb right,
it's not. It's not any kind of as we discussed,
it's not clothing that they're wearing here over their their
long legs.
Speaker 4 (02:35):
It's something else, that's right. It is the bird's poop.
Speaker 3 (02:40):
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 pee. It's all one thing.
Speaker 2 (02:55):
Yes, the glory of the Cloaca, which a long time
listeners to stuff the Blu 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 kloaca.
Speaker 3 (03:09):
Remember it's a classic from many years ago. I think
you and Julie did some cloaca.
Speaker 2 (03:13):
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 creatures as well.
Speaker 4 (03:27):
That's right.
Speaker 3 (03:27):
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 kloaca. So anyway, I got interested in
the concept of eurohydrosis, the idea that birds would be
intentionally having an adaptation to excrete waste all over their
(03:50):
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 Vergel,
Andrea Soriano, Ridondo Auxiliadora Viegas, Jose A Maseroje M. Sanchez Guzman,
(04:17):
and Jorge S.
Speaker 4 (04:18):
Gutierres.
Speaker 3 (04:20):
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 different types of water bags moving around and
reproducing ourselves, so at the extremes you need to manage
(04:43):
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 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
(05:06):
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, generate their own internal heat from metabolism, so
they burn food energy and use homeostatic mechanisms like shivering
(05:28):
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, sometimes called cold blooded animals, regulate their
body temperature mostly with the help of the outside environment.
(05:49):
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 a clean cut. There are a
lot of kind of blurry cases in between, just sort
(06:10):
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 endotherms animals that primarily generate their own
heat through metabolism, they can do a lot more. They
(06:30):
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. They can usually go
(06:53):
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,
(07:14):
and the authors begin the 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,
(07:36):
and the authors say 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
(07:56):
there are many different kinds 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
(08:17):
what feels like fairly warm water, 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 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.
(08:37):
You spend too long in the pool, you really will
start to chill out and you need to get out
of the water and warm up.
Speaker 2 (08:43):
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, on a nice pool
patio on a hot summer day, what are some of
your options. Do you choose the umbrella, do you choose
the pool, do you choose the shade of the house,
(09:04):
and so forth?
Speaker 4 (09:05):
That's right.
Speaker 3 (09:05):
And then there's another class of heat dissipating behaviors which
could be called like postural 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 kind of
(09:25):
try to 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 2 (09:48):
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 (09:59):
Or if you're a bird, you might want to fold
unfold your wings, hold your wings out to let 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 to switch gears into what
(10:22):
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, panting, or increasing
the breathing rate to dissipate more heat from the lungs
(10:45):
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 because maybe because they think it
incorrectly implies it's the exact same thing that dogs do,
but either it's similar either way. For birds, panting involves
(11:09):
rapid breathing with an open mouth, so 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
accompanied by another response called googler fluttering g u l
R fluttering, which means like they would, the bird will
(11:30):
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 the body and help avoid hyperthermia, help the animal
cool down, But they're also very costly. They're costly and
(11:52):
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 that panting in birds can force potentially undesirable
changes in blood chemistry. So if you're an animal in
(12:12):
the wild fighting for survival, you have these physiological mechanisms,
these sort of rapid body adjustments that you can rely
on if you have to, but you would like.
Speaker 4 (12:24):
To avoid them.
Speaker 3 (12:25):
You would like to avoid going into these 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
(12:46):
of this paper introduce a concept from zoology 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 which energy you can take in and
by consequence limits reproductive output. So the author's right that
under this theory, heat dissipation behaviors could really be crucial
(13:10):
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
authors mentioned that the sort of research context of this
paper is that thermoregulatory behaviors and animals are increasingly being
(13:33):
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 attention from people
who study wildlife, especially as the heat stresses of environments
(13:57):
are changing more rapidly. Now, another interesting fact about how
birds protect themselves against overheating has to do with what
the authors call quote unfeathered and well vascularized appendages, meaning
(14:21):
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 not insulated by
feathers and lots of blood flows through them, and for
(14:42):
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 typically have long,
(15:03):
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 to their legs,
(15:24):
constricting the blood vessels down there 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 back to the topic for today,
(15:45):
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
excrita toward their legs, only one leg at a time,
(16:07):
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 flop
down in a chair. You could get out of the
(16:28):
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 2 (16:42):
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 (16:56):
I'm not recommending this as a tactic for human beings.
I don't know that 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.
(17:18):
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 Invention of
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
(17:40):
energy to 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
(18:02):
at the same 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
(18:22):
bottle that 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
(18:44):
have like 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 evaporate from the
hot cloth on the outside through the day under the
hot sun, it sucks heat from the water inside and
(19:05):
makes the water 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
(19:26):
keep hydrated. To 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
(19:49):
system with 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,
(20:12):
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 eurohydrosis and another group to not use it.
(20:34):
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 images of birds doing certain things
(20:55):
and the environmental data about them. So this was not
a 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
or not? So what environmental factors did they find correlating.
Speaker 4 (21:19):
With the use of eurohydrosis? By storks.
Speaker 3 (21:22):
The authors found that high temperatures, high solar radiation, higher
air humidity, and low wind speed were all factors that
would increase the baseline heat stress risk for an endothermic animal,
and storks in environments with all of these conditions were
more likely to engage in eurohydrosis. They also found that
(21:44):
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, all the better, right, Some storks
are not in a position to spend as much time
hanging out in the water.
Speaker 2 (22:05):
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 (22:15):
Now, even storks that sometimes weighed in water do apparently
use eurohydrosis, just less often.
Speaker 4 (22:22):
For these species, it.
Speaker 3 (22:23):
May be more limited to times when circumstances 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
that eurohydrosis correlates to open and warm habitats was confirmed.
Birds that sort of live out in the open in
(22:43):
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
would be correlated to the use of eurohydrosis. The idea
(23:04):
is maybe that birds with darker pigmentation absorb 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
also not strictly supported, though again there's some complications because
(23:28):
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
of this paper predicted. They thought that higher body mass
(23:48):
would predict more eurohydrosis because the animal would have more
water reserves to take advantage of. Like, if you're a
bigger animal, you can drink more water, store more water
in the body. You can also you've got more to
waste in pooping on your own legs to cool off.
But this was actually not the case. This might have
(24:09):
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 groups that practice eurohydrosis, like New World vultures, boobies,
(24:30):
and gannets, they 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
seemed to be some common environmental and physiological pressures at work.
Now some other interesting observations from their conclusion I thought
(24:51):
one was that when comparing different ways of cooling the
body 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
(25:12):
pooping at a lower temperature threshold than the temperature threshold
for panting. 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 an ice water bath. You know, one is like
a more severe, costly activity than the other, and it
(25:32):
seems like for these birds, panting is the more severe,
more costly, and risky activity. 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
(25:55):
by like drooling or licking on themselves on the outside
and then allowing that saliva 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 strongly established, but a
(26:16):
possibility is that there could be a tradeoff between mate
signaling based on the pigmentation of bird legs and the
cooling benefits of euro hydrosis. 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
(26:38):
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 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
(26:58):
and involved a or direct method. And so the second
paper was by again three of the same authors, Kabeo, Vergel,
Viegas and Gutierres, and this one was called keeping Cool
with poop Eurohydrosis lowers leg surface temperature by up to
six degrees celsius in breeding white storks, published in Ecosphere
(27:20):
in twenty twenty three, and this study was a direct
attempt to measure that the magnitude and duration of the
evaporative cooling that you get from eurohydrosis in free ranging birds.
This study used observations of eurohydrosis in white storks or
seconias econia, paired with thermal imaging and microclimate measurements to
(27:42):
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 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
(28:05):
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,
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,
(28:26):
it will dry up, and then it will provide less
of a cooling benefit and may even have some negative effect.
Speaker 4 (28:32):
In fact, if it like cakes on you know.
Speaker 2 (28:35):
Let's keep all of this in mind as we perceive, right.
Speaker 3 (28:39):
So, but then there's the second second thing here. The
selection continues quote. Thus, for your hydrosis 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.
(29:02):
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.
Speaker 4 (29:24):
Wow.
Speaker 2 (29:25):
So it's like any 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 (29:37):
Yeah, that's a great comparison. It'll 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.
Speaker 4 (29:53):
Back and forth.
Speaker 3 (29:55):
Now, I just did want to I mentioned this on
the earlier study, but I did want to emphasize again,
unless you think 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
(30:16):
the heat is therefore crucial to better predict the future
persistence and vulnerability of 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
(30:37):
or worse able to deal with it than others. There
was another question that came out because I saw some
stuff online in discussions about eurohedrosis that was about possible
(30:57):
other functions. It seems pretty clear 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 another role as well, Like I saw
some ideas that it could possibly have an antibacterial function.
Speaker 2 (31:17):
Yeah, and that brings us back to the gross and
wonderful world of vultures. These splendid kings and queens who
keep our streets clear of carcasses and in general are
just great decomposers. There were a few in our neighborhood
not too just a week or so ago. They were
disrupting traffic. But you know, as we went by them,
(31:39):
we saluted them because they were doing the lord's work
out there.
Speaker 4 (31:42):
They're worthy of our respect. Yes.
Speaker 2 (31:45):
So yeah, there's this idea that various New World vultures
are engaging in this kind of you know, possible eurohydrosis,
but maybe not for temperature control purposes. That you know,
they've been observed to do it when it's cold, they've
been serve to do it when it's warm, So what
could the purpose be? And there is this idea that
(32:05):
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 sanitize those legs with an eye,
(32:28):
perhaps with a nice you know, coloacal wash. And so
that is, 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
(32:49):
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 full.
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
(33:09):
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 in US and Canada at any rate,
vulture researchers are prohibited from using leg bands on turkey
(33:32):
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 it's like
(33:54):
too big of a weight for them to fly off with, apparently,
or at least you know, it would get in the
way 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 from birds, I do want to point
(34:17):
out that in looking I'm always interested to see if
there's any kind of mythological or folklore 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 Goal that came out in two
(34:38):
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 are working for him remove
(35:00):
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 Giles
says is apparently connected to observations of the wood stork
who appeared gutless, because they are constantly excreting waste. You mentioned,
(35:25):
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. 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 giving it time at all, is just
(35:47):
going straight through, and therefore, you know, there's just these
kind of you know, ravenous but unsatisfied creatures.
Speaker 3 (35:55):
Interesting, now, I didn't come across a poop count on
the wood stork. But in that one star, yeah there
was the white stork, and it was up to eleven
times per hour.
Speaker 4 (36:04):
Wow, that's a lot.
Speaker 2 (36:06):
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 apparently don't say anything, so
(36:27):
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's maybe concerned more with
the mythic purposes of the tale as opposed to anything else.
(36:48):
And then this bleeds into an 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 4 (37:10):
Interesting.
Speaker 3 (37:10):
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 had
to conserve water resources maximally and did not have ready
(37:34):
access to water bodies.
Speaker 4 (37:36):
Yeah.
Speaker 2 (37:36):
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
He lived nineteen fifty eight through twenty twenty one. He
was a social anthropologist who worked a lot in the Amazon.
Speaker 3 (37:52):
Interesting story. Yeah, yeah, I also was. I did not
think there would be a eurohydrosis related myth, But.
Speaker 2 (38:00):
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. Is this means bare head because we're talking
(38:22):
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 Thermoregulatory Behavior
of eared Seals this is published in the journal Behavior,
they have other means of thermoregulation that become necessary when
(38:43):
these well insulated creatures are out of the water and
caring about on the shore, on the rocks in the sun.
Speaker 3 (38:52):
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 their heat
conserving adaptations are working against them, right.
Speaker 2 (39:14):
And the situation where this becomes essential, especially for the males,
it has to do with their their breeding period because
they you know, they live a lot of their lives
in the water, but they have to 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 fighting and squabbling for territory
(39:37):
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 water is the author points out,
(39:59):
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 have to do other things.
(40:20):
So Gentry 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 you know, rocks of course heat
up in the sun, so being in the shade is
one level of protection, but also being on rocks that
(40:42):
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
(41:03):
the key, because then they'll lay on one side and
extend their now wet rear flipper into the air and
this will be the way they carry out 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 thermal regulation when
(41:23):
they're out on the shore. So, coming back to 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've got to keep the fluids flowing.
Speaker 3 (41:33):
That is so interesting imagining like the sort of the
chain of preparations there I'm thinking about. So the mail
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 2 (41:48):
Now, this is also interesting to think about for me
because I did get to see Galapagos fur seals carrying
out carrying out their various activities on the beach when
I was down at the Galapagos Island, and I didn't
even know to look out for any kind of urination
going on. I don't think I saw any like actual
throwdowns between male seals, but I did get to see
(42:12):
like some of what they're up to. So, yeah, I
wish I'd known to look out for this.
Speaker 3 (42:17):
What does it look What does it look like? Some
we're just trying to like stake out good territory.
Speaker 2 (42:22):
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
(42:44):
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 4 (43:02):
Yeah, don't mess with seals, folks.
Speaker 2 (43:04):
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, catterwalled
a bit, and then she moved on elsewhere. But it
was like, I don't know, it kind of felt like
(43:24):
she was being a little petty. But fair enough, this
beach belongs to you. I'm just visiting.
Speaker 4 (43:29):
Very magnanimous.
Speaker 2 (43:30):
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 the moment, I mentioned the Galapagos and
I mistook my memory of Galapagos sea lions for Galapagos
(43:53):
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 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
(44:15):
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,
speaking of the Glapagos, 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
(44:38):
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
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 too warm. Things is
(45:00):
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 the opposite direction, right, you know, can we just
pee in our dive suits in order to warm things up?
(45:22):
And you know, I was able to find a full
article about this on dive SSI dot com. That's Scuba
School's International.
Speaker 4 (45:30):
That's beautiful. Well what's the word?
Speaker 2 (45:33):
All right? 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 scuba divers that that
(45:53):
if you get in a little cold, will pee in
your suit and then all 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 in the extremities, and
(46:14):
blood's 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
increases 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
(46:34):
a 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,
(46:55):
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 (47:06):
Nothing gold can stay.
Speaker 2 (47:08):
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? I mean, how many times can will you
urinate in your suit on a given dive or snorkel?
(47:31):
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 (47:41):
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 losing warmth by peeing, but it's it feels warm
on the outside.
Speaker 2 (47:58):
Right, you're going to 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 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 you get used to it and you carry on.
(48:21):
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
that being said, the article stresses that peeing in your
(48:42):
wet suit is a common practice and 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 thoroughly wash it out,
(49:02):
you could get some uh some some some urine odors
you know, in the material and so forth. But uh,
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 (49:18):
You know, correct me if I'm wrong. But I bet
a lot of people don't own their own dive suits,
do your kind? Is it a rental situation?
Speaker 2 (49:24):
Yeah? Yeah, I mean now that you mentioned it, like
the dive suit I urinated in was definitely not mine,
in no shape was provided for me. And uh, yeah,
I trust that they sprayed it out afterwards. I guess
though it didn't seem gross when I put it on.
So uh And I imagine a lot of people have
peede in that suit.
Speaker 4 (49:45):
Sound like everybody does it. I'm sure they wash them
real good.
Speaker 2 (49:48):
I would love to hear from folks out there who've
done like a lot of like scuba and snorkeling in
wet suits. And uh, you can add your own, you know,
two cents to this whole discussion.
Speaker 3 (50:02):
Well, Rob, this topic went places I did not expect,
but I have found great delight in the twists and turns.
Speaker 2 (50:08):
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 (50:15):
Hey, but if you're somebody who happens to see storks, vultures, condors, ganets,
boobies in the wild and you catch them with like
seeing this taking place, let us know, do you have
any pictures what's going on?
Speaker 2 (50:27):
Yeah, that's right, we want natural world observations as well
as reports on adventures and peeing yourself.
Speaker 4 (50:34):
Please no pictures of human just the.
Speaker 2 (50:37):
Birds, just the birds place 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
(50:57):
for those episodes. You can find us on Instagram. We
are st b y M podcast There.
Speaker 3 (51:02):
Huge thanks 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 1 (51:24):
Stuff to Blow Your Mind is production of iHeartRadio. For
more podcasts from my Heart Radio, visit the iHeartRadio app,
Apple Podcasts, or wherever you're listening to your favorite shows.
Welcome to Stuff to Blow Your Mind, the production of iHeartRadio.
Speaker 2 (00:12):
Hey you welcome to Stuff to Blow your Mind. My
name is Robert Lamb.
Speaker 3 (00:16):
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
fancy 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.
Speaker 4 (00:39):
Yeah.
Speaker 2 (00:39):
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 (00:51):
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
(01:11):
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 lucocephala, which
(01:37):
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
(01:59):
that we're going to talk about just a minute. You
can see in patches that the legs and feet have
a natural pigmentation.
Speaker 4 (02:06):
They've got maybe a.
Speaker 3 (02:07):
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.
And if you had to guess what it is, what
would you think it is? Indeed, what you're probably.
Speaker 2 (02:23):
Thinking, it's not some sort of a glittery bomb right,
it's not. It's not any kind of as we discussed,
it's not clothing that they're wearing here over their their
long legs.
Speaker 4 (02:35):
It's something else, that's right. It is the bird's poop.
Speaker 3 (02:40):
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 pee. It's all one thing.
Speaker 2 (02:55):
Yes, the glory of the Cloaca, which a long time
listeners to stuff the Blu 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 kloaca.
Speaker 3 (03:09):
Remember it's a classic from many years ago. I think
you and Julie did some cloaca.
Speaker 2 (03:13):
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 creatures as well.
Speaker 4 (03:27):
That's right.
Speaker 3 (03:27):
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 kloaca. So anyway, I got interested in
the concept of eurohydrosis, the idea that birds would be
intentionally having an adaptation to excrete waste all over their
(03:50):
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 Vergel,
Andrea Soriano, Ridondo Auxiliadora Viegas, Jose A Maseroje M. Sanchez Guzman,
(04:17):
and Jorge S.
Speaker 4 (04:18):
Gutierres.
Speaker 3 (04:20):
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 different types of water bags moving around and
reproducing ourselves, so at the extremes you need to manage
(04:43):
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 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
(05:06):
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, generate their own internal heat from metabolism, so
they burn food energy and use homeostatic mechanisms like shivering
(05:28):
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, sometimes called cold blooded animals, regulate their
body temperature mostly with the help of the outside environment.
(05:49):
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 a clean cut. There are a
lot of kind of blurry cases in between, just sort
(06:10):
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 endotherms animals that primarily generate their own
heat through metabolism, they can do a lot more. They
(06:30):
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. They can usually go
(06:53):
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,
(07:14):
and the authors begin the 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,
(07:36):
and the authors say 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
(07:56):
there are many different kinds 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
(08:17):
what feels like fairly warm water, 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 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.
(08:37):
You spend too long in the pool, you really will
start to chill out and you need to get out
of the water and warm up.
Speaker 2 (08:43):
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, on a nice pool
patio on a hot summer day, what are some of
your options. Do you choose the umbrella, do you choose
the pool, do you choose the shade of the house,
(09:04):
and so forth?
Speaker 4 (09:05):
That's right.
Speaker 3 (09:05):
And then there's another class of heat dissipating behaviors which
could be called like postural 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 kind of
(09:25):
try to 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 2 (09:48):
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 (09:59):
Or if you're a bird, you might want to fold
unfold your wings, hold your wings out to let 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 to switch gears into what
(10:22):
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, panting, or increasing
the breathing rate to dissipate more heat from the lungs
(10:45):
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 because maybe because they think it
incorrectly implies it's the exact same thing that dogs do,
but either it's similar either way. For birds, panting involves
(11:09):
rapid breathing with an open mouth, so 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
accompanied by another response called googler fluttering g u l
R fluttering, which means like they would, the bird will
(11:30):
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 the body and help avoid hyperthermia, help the animal
cool down, But they're also very costly. They're costly and
(11:52):
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 that panting in birds can force potentially undesirable
changes in blood chemistry. So if you're an animal in
(12:12):
the wild fighting for survival, you have these physiological mechanisms,
these sort of rapid body adjustments that you can rely
on if you have to, but you would like.
Speaker 4 (12:24):
To avoid them.
Speaker 3 (12:25):
You would like to avoid going into these 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
(12:46):
of this paper introduce a concept from zoology 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 which energy you can take in and
by consequence limits reproductive output. So the author's right that
under this theory, heat dissipation behaviors could really be crucial
(13:10):
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
authors mentioned that the sort of research context of this
paper is that thermoregulatory behaviors and animals are increasingly being
(13:33):
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 attention from people
who study wildlife, especially as the heat stresses of environments
(13:57):
are changing more rapidly. Now, another interesting fact about how
birds protect themselves against overheating has to do with what
the authors call quote unfeathered and well vascularized appendages, meaning
(14:21):
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 not insulated by
feathers and lots of blood flows through them, and for
(14:42):
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 typically have long,
(15:03):
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 to their legs,
(15:24):
constricting the blood vessels down there 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 back to the topic for today,
(15:45):
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
excrita toward their legs, only one leg at a time,
(16:07):
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 flop
down in a chair. You could get out of the
(16:28):
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 2 (16:42):
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 (16:56):
I'm not recommending this as a tactic for human beings.
I don't know that 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.
(17:18):
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 Invention of
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
(17:40):
energy to 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
(18:02):
at the same 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
(18:22):
bottle that 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
(18:44):
have like 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 evaporate from the
hot cloth on the outside through the day under the
hot sun, it sucks heat from the water inside and
(19:05):
makes the water 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
(19:26):
keep hydrated. To 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
(19:49):
system with 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,
(20:12):
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 eurohydrosis and another group to not use it.
(20:34):
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 images of birds doing certain things
(20:55):
and the environmental data about them. So this was not
a 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
or not? So what environmental factors did they find correlating.
Speaker 4 (21:19):
With the use of eurohydrosis? By storks.
Speaker 3 (21:22):
The authors found that high temperatures, high solar radiation, higher
air humidity, and low wind speed were all factors that
would increase the baseline heat stress risk for an endothermic animal,
and storks in environments with all of these conditions were
more likely to engage in eurohydrosis. They also found that
(21:44):
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, all the better, right, Some storks
are not in a position to spend as much time
hanging out in the water.
Speaker 2 (22:05):
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 (22:15):
Now, even storks that sometimes weighed in water do apparently
use eurohydrosis, just less often.
Speaker 4 (22:22):
For these species, it.
Speaker 3 (22:23):
May be more limited to times when circumstances 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
that eurohydrosis correlates to open and warm habitats was confirmed.
Birds that sort of live out in the open in
(22:43):
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
would be correlated to the use of eurohydrosis. The idea
(23:04):
is maybe that birds with darker pigmentation absorb 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
also not strictly supported, though again there's some complications because
(23:28):
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
of this paper predicted. They thought that higher body mass
(23:48):
would predict more eurohydrosis because the animal would have more
water reserves to take advantage of. Like, if you're a
bigger animal, you can drink more water, store more water
in the body. You can also you've got more to
waste in pooping on your own legs to cool off.
But this was actually not the case. This might have
(24:09):
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 groups that practice eurohydrosis, like New World vultures, boobies,
(24:30):
and gannets, they 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
seemed to be some common environmental and physiological pressures at work.
Now some other interesting observations from their conclusion I thought
(24:51):
one was that when comparing different ways of cooling the
body 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
(25:12):
pooping at a lower temperature threshold than the temperature threshold
for panting. 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 an ice water bath. You know, one is like
a more severe, costly activity than the other, and it
(25:32):
seems like for these birds, panting is the more severe,
more costly, and risky activity. 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
(25:55):
by like drooling or licking on themselves on the outside
and then allowing that saliva 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 strongly established, but a
(26:16):
possibility is that there could be a tradeoff between mate
signaling based on the pigmentation of bird legs and the
cooling benefits of euro hydrosis. 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
(26:38):
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 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
(26:58):
and involved a or direct method. And so the second
paper was by again three of the same authors, Kabeo, Vergel,
Viegas and Gutierres, and this one was called keeping Cool
with poop Eurohydrosis lowers leg surface temperature by up to
six degrees celsius in breeding white storks, published in Ecosphere
(27:20):
in twenty twenty three, and this study was a direct
attempt to measure that the magnitude and duration of the
evaporative cooling that you get from eurohydrosis in free ranging birds.
This study used observations of eurohydrosis in white storks or
seconias econia, paired with thermal imaging and microclimate measurements to
(27:42):
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 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
(28:05):
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,
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,
(28:26):
it will dry up, and then it will provide less
of a cooling benefit and may even have some negative effect.
Speaker 4 (28:32):
In fact, if it like cakes on you know.
Speaker 2 (28:35):
Let's keep all of this in mind as we perceive, right.
Speaker 3 (28:39):
So, but then there's the second second thing here. The
selection continues quote. Thus, for your hydrosis 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.
(29:02):
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.
Speaker 4 (29:24):
Wow.
Speaker 2 (29:25):
So it's like any 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 (29:37):
Yeah, that's a great comparison. It'll 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.
Speaker 4 (29:53):
Back and forth.
Speaker 3 (29:55):
Now, I just did want to I mentioned this on
the earlier study, but I did want to emphasize again,
unless you think 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
(30:16):
the heat is therefore crucial to better predict the future
persistence and vulnerability of 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
(30:37):
or worse able to deal with it than others. There
was another question that came out because I saw some
stuff online in discussions about eurohedrosis that was about possible
(30:57):
other functions. It seems pretty clear 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 another role as well, Like I saw
some ideas that it could possibly have an antibacterial function.
Speaker 2 (31:17):
Yeah, and that brings us back to the gross and
wonderful world of vultures. These splendid kings and queens who
keep our streets clear of carcasses and in general are
just great decomposers. There were a few in our neighborhood
not too just a week or so ago. They were
disrupting traffic. But you know, as we went by them,
(31:39):
we saluted them because they were doing the lord's work
out there.
Speaker 4 (31:42):
They're worthy of our respect. Yes.
Speaker 2 (31:45):
So yeah, there's this idea that various New World vultures
are engaging in this kind of you know, possible eurohydrosis,
but maybe not for temperature control purposes. That you know,
they've been observed to do it when it's cold, they've
been serve to do it when it's warm, So what
could the purpose be? And there is this idea that
(32:05):
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 sanitize those legs with an eye,
(32:28):
perhaps with a nice you know, coloacal wash. And so
that is, 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
(32:49):
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 full.
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
(33:09):
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 in US and Canada at any rate,
vulture researchers are prohibited from using leg bands on turkey
(33:32):
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 it's like
(33:54):
too big of a weight for them to fly off with, apparently,
or at least you know, it would get in the
way 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 from birds, I do want to point
(34:17):
out that in looking I'm always interested to see if
there's any kind of mythological or folklore 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 Goal that came out in two
(34:38):
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 are working for him remove
(35:00):
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 Giles
says is apparently connected to observations of the wood stork
who appeared gutless, because they are constantly excreting waste. You mentioned,
(35:25):
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. 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 giving it time at all, is just
(35:47):
going straight through, and therefore, you know, there's just these
kind of you know, ravenous but unsatisfied creatures.
Speaker 3 (35:55):
Interesting, now, I didn't come across a poop count on
the wood stork. But in that one star, yeah there
was the white stork, and it was up to eleven
times per hour.
Speaker 4 (36:04):
Wow, that's a lot.
Speaker 2 (36:06):
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 apparently don't say anything, so
(36:27):
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's maybe concerned more with
the mythic purposes of the tale as opposed to anything else.
(36:48):
And then this bleeds into an 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 4 (37:10):
Interesting.
Speaker 3 (37:10):
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 had
to conserve water resources maximally and did not have ready
(37:34):
access to water bodies.
Speaker 4 (37:36):
Yeah.
Speaker 2 (37:36):
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
He lived nineteen fifty eight through twenty twenty one. He
was a social anthropologist who worked a lot in the Amazon.
Speaker 3 (37:52):
Interesting story. Yeah, yeah, I also was. I did not
think there would be a eurohydrosis related myth, But.
Speaker 2 (38:00):
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. Is this means bare head because we're talking
(38:22):
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 Thermoregulatory Behavior
of eared Seals this is published in the journal Behavior,
they have other means of thermoregulation that become necessary when
(38:43):
these well insulated creatures are out of the water and
caring about on the shore, on the rocks in the sun.
Speaker 3 (38:52):
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 their heat
conserving adaptations are working against them, right.
Speaker 2 (39:14):
And the situation where this becomes essential, especially for the males,
it has to do with their their breeding period because
they you know, they live a lot of their lives
in the water, but they have to 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 fighting and squabbling for territory
(39:37):
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 water is the author points out,
(39:59):
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 have to do other things.
(40:20):
So Gentry 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 you know, rocks of course heat
up in the sun, so being in the shade is
one level of protection, but also being on rocks that
(40:42):
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
(41:03):
the key, because then they'll lay on one side and
extend their now wet rear flipper into the air and
this will be the way they carry out 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 thermal regulation when
(41:23):
they're out on the shore. So, coming back to 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've got to keep the fluids flowing.
Speaker 3 (41:33):
That is so interesting imagining like the sort of the
chain of preparations there I'm thinking about. So the mail
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 2 (41:48):
Now, this is also interesting to think about for me
because I did get to see Galapagos fur seals carrying
out carrying out their various activities on the beach when
I was down at the Galapagos Island, and I didn't
even know to look out for any kind of urination
going on. I don't think I saw any like actual
throwdowns between male seals, but I did get to see
(42:12):
like some of what they're up to. So, yeah, I
wish I'd known to look out for this.
Speaker 3 (42:17):
What does it look What does it look like? Some
we're just trying to like stake out good territory.
Speaker 2 (42:22):
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
(42:44):
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 4 (43:02):
Yeah, don't mess with seals, folks.
Speaker 2 (43:04):
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, catterwalled
a bit, and then she moved on elsewhere. But it
was like, I don't know, it kind of felt like
(43:24):
she was being a little petty. But fair enough, this
beach belongs to you. I'm just visiting.
Speaker 4 (43:29):
Very magnanimous.
Speaker 2 (43:30):
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 the moment, I mentioned the Galapagos and
I mistook my memory of Galapagos sea lions for Galapagos
(43:53):
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 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
(44:15):
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,
speaking of the Glapagos, 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
(44:38):
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
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 too warm. Things is
(45:00):
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 the opposite direction, right, you know, can we just
pee in our dive suits in order to warm things up?
(45:22):
And you know, I was able to find a full
article about this on dive SSI dot com. That's Scuba
School's International.
Speaker 4 (45:30):
That's beautiful. Well what's the word?
Speaker 2 (45:33):
All right? 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 scuba divers that that
(45:53):
if you get in a little cold, will pee in
your suit and then all 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 in the extremities, and
(46:14):
blood's 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
increases 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
(46:34):
a 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,
(46:55):
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 (47:06):
Nothing gold can stay.
Speaker 2 (47:08):
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? I mean, how many times can will you
urinate in your suit on a given dive or snorkel?
(47:31):
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 (47:41):
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 losing warmth by peeing, but it's it feels warm
on the outside.
Speaker 2 (47:58):
Right, you're going to 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 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 you get used to it and you carry on.
(48:21):
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
that being said, the article stresses that peeing in your
(48:42):
wet suit is a common practice and 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 thoroughly wash it out,
(49:02):
you could get some uh some some some urine odors
you know, in the material and so forth. But uh,
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 (49:18):
You know, correct me if I'm wrong. But I bet
a lot of people don't own their own dive suits,
do your kind? Is it a rental situation?
Speaker 2 (49:24):
Yeah? Yeah, I mean now that you mentioned it, like
the dive suit I urinated in was definitely not mine,
in no shape was provided for me. And uh, yeah,
I trust that they sprayed it out afterwards. I guess
though it didn't seem gross when I put it on.
So uh And I imagine a lot of people have
peede in that suit.
Speaker 4 (49:45):
Sound like everybody does it. I'm sure they wash them
real good.
Speaker 2 (49:48):
I would love to hear from folks out there who've
done like a lot of like scuba and snorkeling in
wet suits. And uh, you can add your own, you know,
two cents to this whole discussion.
Speaker 3 (50:02):
Well, Rob, this topic went places I did not expect,
but I have found great delight in the twists and turns.
Speaker 2 (50:08):
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 (50:15):
Hey, but if you're somebody who happens to see storks, vultures, condors, ganets,
boobies in the wild and you catch them with like
seeing this taking place, let us know, do you have
any pictures what's going on?
Speaker 2 (50:27):
Yeah, that's right, we want natural world observations as well
as reports on adventures and peeing yourself.
Speaker 4 (50:34):
Please no pictures of human just the.
Speaker 2 (50:37):
Birds, just the birds place 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
(50:57):
for those episodes. You can find us on Instagram. We
are st b y M podcast There.
Speaker 3 (51:02):
Huge thanks 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 1 (51:24):
Stuff to Blow Your Mind is production of iHeartRadio. For
more podcasts from my Heart Radio, visit the iHeartRadio app,
Apple Podcasts, or wherever you're listening to your favorite shows.
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