August 9, 2025 • 43 mins
In this classic episode of Stuff to Blow Your Mind, Robert and Joe discuss the curious biology of North America’s horned lizard – especially their ability to squirt blood from their eyes – as well as some culture and history surrounding their existence. (originally published 8/13/2024)
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Episode Transcript
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Speaker 1 (00:06):
Hey, welcome to Stuff to Blow your Mind. This is
Robert Lamb. Today is Saturday, so we have an older
episode of Stuff to Blow Your Mind to share with
you here. This one was originally published eight thirteen, twenty
twenty four. It is Blood Squirting from the Lizard's Eye,
Part one.
Speaker 2 (00:24):
Welcome to Stuff to Blow Your Mind, production of iHeartRadio.
Speaker 1 (00:34):
Hey, welcome to Stuff to Blow your Mind. My name
is Robert Lamb.
Speaker 3 (00:38):
And I am Joe McCormick. And today on Stuff to
Blow Your Mind, we are going to be talking about
an animal, about the horned lizard or frenosoma, a genus
of lizard native to North America, also known as horned
toads or horny toads. From what I've been reading, I
think the people in the biological sciences prefer the more
(00:58):
accurate lizard, applely because they are certainly not toads, though
there are reasons for calling them toads, mainly that they
look like toads.
Speaker 1 (01:07):
Now, we're going to probably try and stick to horned lizard.
I'm probably going to say horned lizard because I like
using the more antiquated term and it sounds more demonic.
But we also might say, horny toad, horned toad, horn toad,
and so forth.
Speaker 3 (01:22):
Throughout the episode, Horned Lizard makes me think learned lizard.
You know, doesn't it suggest a kind of wisdom?
Speaker 1 (01:29):
Yeah? Yeah, sometimes lizards can appear quite wise, so I
buy that.
Speaker 3 (01:35):
And in fact, you might even think about some of
the species of horned lizards as especially wise or discerning
among the reptile kind, because they, as we get into
later in this episode, they have some anti predator strategies
that really require snap judgment calls about say what type
of predator you're dealing with?
Speaker 1 (01:54):
That's right? And I don't know if we'll get into
it in this episode or the next, but among the Navajo,
among the DNA people, they're sometimes called grandfather, so I
think there is often that vibe of maybe sort of
wisdom and power to them.
Speaker 3 (02:07):
Though I have to admit I did come to this
topic through more base and if you know, us predictable routes.
So my window into talking about horned lizards was the
fact that for sci fi horror nerds like us, it's
alien summer. Would you agree, Rob.
Speaker 1 (02:22):
Oh, yeah, it's been an alien summer for me. We've
been chatting about alien movies and the upcoming alien movie.
So yeah, there's a lot of excitement in the air.
Speaker 3 (02:30):
Yeah, there's a new alien movie coming out in theaters
later this week, Alien Romulus. Of course, there's no guarantee
ahead of time it's going to be good. I don't
think they've even released the critics embargo yet. But I'm
just recklessly letting myself get excited regardless tempering expectations is
for the week.
Speaker 1 (02:47):
That's right, Say yes to Xenomorph and then figure the
rest out later.
Speaker 3 (02:52):
You know, if I'm disappointed, I'm disappointed, It'll be okay.
So we've had Aliens on the brain for a few
months here, and we've covered a couple of Aliens copycat
movies on Weird House Cinema. We'll probably do at least
one more, I think that's right.
Speaker 1 (03:05):
We also had a seven part Monster Fact series on
the various creatures and organisms of the alien universe, with
part seven publishing this week.
Speaker 3 (03:12):
Mm hmm. But so we've got all this excitement running
through us, and I was looking to find some real
world biology to cover that had parallels an alien. We've
already done a lot of topics along these lines in
the past, and the idea of the xenomorph's weaponized blood
took hold. So in the Alien movies if you haven't
seen them, the creature in these movies has extremely potent
(03:37):
acid for blood, which appears to serve as a defense strategy.
So if you cause injury to one of the Xenomorphs,
you are likely to get some of its blood on
yourself or on your critical infrastructure, such as the inside
of your spacecraft hull, and that blood will burn through
bodies and space ships alike. So, as observed by the
(03:58):
characters in the first movie, there's real danger in injuring
the creature. How do you fight it?
Speaker 1 (04:03):
That's right. It's also worth pointing out that there is
at least some acid fluid as projectile in the xenomorph world.
The most, I would say, I guess the key example
would be in nineteen seventy nine's Alien the first film,
as we see that emergent face hugger seem to use
acidic secretions to burn through Caine's helmet in order to
(04:24):
access his face. Now, naturally, given that certain wounds, especially
lethal wounds to a Xenomorph, could result in a jet
of acidic blood, we could easily classify that as a
form of defensive spray, and then in Alien three and
Alien Resurrection, the third and fourth movies in the franchise,
we actually see xenomorphs using an offensive acid spray attack,
(04:46):
And of course this has also been used to various
effects in Alien video games for ranged enemies, as well
as in Alien comic books and so forth. Also worth
pointing out that, given our current Mortal Kombat discussions on
Weird House Cinema, the acid spit is one of the
signature moves of the green clad Ninja reptile.
Speaker 3 (05:05):
Is it really a spit because the animation looks to
me more like projectile vomit.
Speaker 1 (05:10):
I think it depends. At least in the first game.
He was in Mortal Kombat too, he would definitely spit.
It was like a kind of a sound over and
over again, and I think it got a little more
vomity later on.
Speaker 3 (05:22):
Okay, Now, of course, it's fairly common in the natural
world to find animals that produce some kind of toxic
defensive fluid that they use to protect themselves against predators
or attack prey. But what seemed less common, though perhaps
more common than you would think, was that the defensive
fluid in question was actually the animal's own blood.
Speaker 1 (05:46):
That's right, because a part of the logic here, of course,
is we tend to think vampire like when we think
about an organism's blood. Right, it's part of the prize,
it's part of the predator's claim. So broadly speaking, it would,
on the surface anyway, seem illogical to think that a
predator could be harmed by blood of its prey.
Speaker 3 (06:01):
But here is where the horned lizard comes in. If
you know one thing about the horned lizard, it is
probably that these various species of lizards have a defensive
adaptation of squirting blood out of their eyes.
Speaker 1 (06:16):
That's right. They're kind of Internet famous for this, a
lot of clips, a lot of a lot of animations
and videos. I should also add that if you know
one thing, you should probably know two things. Also, that
there to some extent horned up, right, because right, I
call them horned lizards, right.
Speaker 3 (06:33):
But while lots of animals are spiky or horned in
some way, I would say that the blood squirting out
of the eyes is such a shocking behavior, such a
bizarre and seemingly rare adaptation, that you would almost have
to wonder if it's not real, Like, is that something
people just made up or does that really happen? And
(06:54):
according to the author of a book that I'm going
to cite in this episode, reports of it have sometimes
in the past been dismissed as tall tales, but they're
not tall tales. The Horned Blizzard's weaponized blood is absolutely real,
and it is the subject of some interesting scientific investigation.
Speaker 1 (07:11):
So this is going to be really fun to get
into now. When we were doing our pre research, though, Joe,
you brought up a resource that we've looked to in
the past, and that's the California herbs dot com website
where they have a wonderful I mean it's not just
about this, but they have a huge listing of various
herp appearances in various films, many of which are very
(07:33):
much in the domain of weird house cinema meaning reptiles, yes, yeah, yeah,
for herpetologist cinema files. And they have a list there
that you shared with me of horned lozerds in movies,
and there are a few that I was familiar with,
you know, because they're pretty popular films. I think what
outlot Josie Wales is on there.
Speaker 3 (07:54):
Yeah, but they they are apparently a number of you know,
westerns I guess where there are horned lizards, which makes
sense because you know, you find a lot of these
several of these species are very common in the American Southwest.
Speaker 1 (08:10):
But also Jodroowski's Holy Mountain is included there, his film
from nineteen seventy three that does have a very memorable
hert scene, though it may contain shots of actual hurts
being exploded with fireworks, so you know, go into that
one with a certain amount of caution. But it's I mean,
it's Holy Mountains, so I'd advise a great deal of
content consideration before you watch it. Anyway, It's kind of
(08:32):
a titan of surreal cinema and an important film when
you're looking at weird psychotronic pictures and you know, Mexican
cinema certainly cinema of the nineteen seventies. But it is
not for everyone.
Speaker 3 (08:43):
Yeah, that's not movie Night with the grandparents.
Speaker 1 (08:46):
Yeah, I believe the scene in question. It's been a
long time since I've seen it, and I have only
seen it like used to. The only way you could
watch it would be like a rip of a Japanese
laser disc, and they're much better sources for it available now,
But there is an extended scene where the conquest of
Mexico is recreated with frogs and toads and lizards standing
(09:08):
in for the various actors and sides in this conflict.
Speaker 3 (09:13):
I did not remember that detail. There's a lot I've
forgotten about Holy Mountain.
Speaker 1 (09:17):
So I would say cameo appearance by the horned lizard. Now,
it's worth noting at the top here that we're not
dealing with a single species when we're discussing horned lizards,
but rather an entire genus of North American lizards, and
that's Phinosoma, including some twenty one species which range as
far north as parts of Canada and on the southern
end range all the way through Mexico and into Guatemala.
(09:39):
And of these again, somewhere around twenty one species, at
least eight species squirt blood from the eye region. So
just an example of range here, there's the greater short
horned lizard or Hernandez is short horned lizard, and it
can be found as far north as southern Saskatchewan and
Alberta and south into the Texas Panhandle in central Mexico.
(10:00):
And this is one of the species of bloodshooters.
Speaker 3 (10:03):
Yeah, that's right. But as you said, Rob, the various
species of horned lizards can be found all over the
part of North America, from down in southern Mexico all
the way up to the southern part of Canada. And
you can look up maps that show you sort of
different estimated ranges of the different species. But yeah, you'll
find them all throughout the arid and semi arid regions
(10:26):
of the North American West. Here, I think it would
be a good place to introduce one of my major
sources for this episode, which is a book called Introduction
to Horned Lizards of North America by Wade C. Sherbrook.
This was published by University of California Press in two
thousand and three, and the author, Wade Sherbrooke, was director
(10:46):
of the Southwestern Research Station of the American Museum of
Natural History, and so one of the questions Sherbrooke addresses
in the introduction of this book is why are horned
lizards commonly referred to as toads, horned toads, horny toads. Well,
they really do kind of look like toads. They tend
(11:07):
to have a wide body when viewed from above, especially
in certain defensive postures where they sort of flatten and
widen their bodies out to create to sort of turn
their backs into a shield. They tend to for lizards
have a short, blunt snout which can resemble a toad's head,
and they also have an awkward walking gait. They tend
(11:30):
to have a camouflaged appearance which helps them blend into
their often sandy or gravelly surroundings, and this can resemble
the model color patterns and bumpy texture you would see
on the backs of some toads, so in lots of
different ways they look like toads, and this led to
the name of their genus. Frinosoma means toad body, phrenoss
(11:50):
toad and soma of course means body, toad body, total
toad body to add to the toad comparisons to make
them even more of a toad body. Can observe how
they eat. Now, the different species of horned lizards have
some different different diets. Some are more sort of taking
what they can get than others, but some are quite
(12:12):
specialized to eating insects and specifically ants, specifically even more
harvester ants. And if you watch the horned lizards eat
harvester ants. When they specialize in this food source, they
have a kind of a sticky, flicking tongue action, much
like we associate with toads and frogs. I was reading
(12:33):
in one part of the Sherbrook book about how exactly
it is that these horned lizards can eat these incredibly
venomous ants, and apparently they have a strategy of like
flicking them into the mouth, and then as they swallow
the ant, the ant becomes covered in this layer of
mucus that comes out of glands in the lizard's throat,
(12:55):
and this coating of mucus surrounds the ant as the
ant is is digested and essentially disables it from biting
or stinging the lizard from the inside until it is
well dead and able to be digested. And these lizards
have to eat a lot of these ants because ants
are not super nutritious like they've got There's not a
(13:17):
lot of meat on that bone. It's mostly bone.
Speaker 1 (13:20):
That's right. Like For instance, one of the other big
ant eaters out there is of course the mammalian ant eater,
and they are known to eat tons of ants and termites.
I've seen estimates of like thirty thousand ants and termites
a day, But even that is still a low calorie diet,
and it's one of the reasons that we think that
ant eaters have one of the lowest mammalian body temperatures.
(13:40):
But in terms of the the what we're dealing with here,
the horned lizards consumption of ants, I found an interesting
article that answers the question, well, how do they eat
them safely? This was from two thousand and eight published
in the journal jazz A by Sherbrooke and Schwink, And
the answer is in the title Horned lizards Incapacity Dangerous
ant prey with mucus. And we've already touched on the
(14:03):
main aspect of this, but they provide one more little
detail that I really like. They write, quote, we show
that they're derived feeding kind of mattics that are associated
with unique mucus secreting hyrngel papilia that apparently serve to
immobilize and incapacitate dangerous ants as they are swallowed by
compacting them and binding them in mucus trans And then
(14:25):
they later add the detail ants extracted from fresh killed
horned lizard's stomachs are curled ventrally into balls and bound
in mucus.
Speaker 3 (14:35):
Take an ant as you're swallowing it, coat it with slime,
and wadd it up into a ball so that you
can digest it without it getting into trouble inside your
digestive tract. That's right, Roll them up, all right, So
(14:58):
that is horned lizards as predators. But I wanted to
focus for the majority of today's episode on horned lizards
as prey because it is, of course in their role
as prey and in their anti predator defense strategies that
we see the jets of blood emerge from the eyes.
So here I want to go back to that book
I mentioned by Wade Sherbrook. He has an excellent section
(15:20):
in this book called Enemies and Defense, which sort of
covers a nearly comprehensive list of different sort of predator
prey relationships between horned lizard species and the predators that
target them, and the strategies they have for resisting these predators. So,
as we alluded to earlier, horned lizards are of course
(15:43):
covered in spikes and scales. This is a pretty sophisticated
armor defense. If you've never seen what a horned lizard
looks like by the way, you should look one up.
I mean, first of all, they are beautiful, but this
will give you a better idea of what we're talking
about as we continually reference the armour moving on. They
tend to have spikes and scales along different parts of
(16:05):
their bodies, such as sort of spiky flank protrusions running
down the lateral sides of the body, but then also
sometimes some kind of bumpy or tough coverings on the back,
and then especially bony spike protrusions around the crown of
the head. So some of the spiky looking things, usually
the smaller ones are just more modified scales, but the
(16:29):
spikes around the head are actually like hard, sharp bony
spikes now covered in spikes and scales. As they are,
you might not think that a horned lizard would look
very appetizing, but you know, out here in the arid
and semi arid regions of the American West, many predators
will take whatever they can get, and so horned lizards
(16:49):
are indeed a prey animal to many species of predators.
Juveniles are the most vulnerable to predation. They're smaller and
they have less developed armor, so many are eaten between
the time they hatch from their eggs and the first hibernation.
But Sherbrooke in this chapter gets into a list of
different predators, and the first one I want to look
(17:10):
at is his section on the long nosed leopard lizard
or the Gambelia whizly zennii. These are worth looking up
a picture of as well, because while they're not very
interesting in terms of shape, they're just sort of like
larger looking predatory lizards. They do have a truly leopard
looking coloration pattern.
Speaker 1 (17:31):
Yeah. Yeah, they're quite quite fetching in their own right.
Speaker 3 (17:33):
So these lizards will frequently attack and eat horned lizards,
especially juveniles, and the general strategy here is not super complicated.
It is to bite them near the head and then
swallow them whole head first. You know, this is just
me reasoning from the pictures, but the sort of backwards
pointing orientation of the head spikes, because they sort of
(17:55):
extend backward from the head like a crown, it makes
it seem like it would probably be easier to swallow
a horned lizard head first rather than tail first, Like
if you went backwards, I would think the spikes would
would be more likely to catch like hooks in the
lining of the throat and the digestive system. But it
also seems like eating one of these things head first
(18:16):
would be a very no going back scenario. You know,
once you start eating a big one, you're committed.
Speaker 1 (18:21):
Yeah, yeah, you can't put it in reverse.
Speaker 3 (18:24):
Sherbrook says in the book about defensive strategies that when
attacked by a leopard lizard a horned lizard, and again,
defensive strategy is very somewhat by species, so we'll be
speaking in some generalities here, but the horned lizard will
often try to defend itself by flattening out its back
into a wide shield shape so it wants to look
(18:46):
as wide as possible, and then tilting and orienting its
armored shield back toward the predator. And again, adults with
well developed armor are much less vulnerable to leopard lizards.
The next category is birds. A number of different birds
prey on horned lizards. Sherbroke mentions hawks such as the
(19:07):
red shouldered hawk or buteolineatis, but also smaller birds like
the prairie falcon, the American kestrel, and the loggerhead shrike.
Predatory birds with powerful talons and beaks have an advantage
when preying on these lizards because they have the ability
to tear the lizard apart and eat it piece by piece,
(19:30):
making it a somewhat easier proposition to consume that this
spiky animal as opposed to an armored adult that needs
to be swallowed whole. However, it does still come with risks.
Sherbrooke mentions one case of a red shouldered hawk that
was found dead after having eaten a couple of Texas
horned lizards. Apparently one of the horns had pierced through
(19:52):
the hawk's throat from the inside. Oh, and I can't
help but apply like a human level of grossed out
to this. Like I know it's just part of the
you know, their way of making a living, but I
cannot imagine eating something this spiky.
Speaker 1 (20:09):
And it's like a like a like a wheat then,
except even worse right.
Speaker 3 (20:14):
Yeah, Oh, it's like you know, you ever think when
you're like eating a tortilla chip and you don't chew
it upright and you get a shard caught in your throat. Yeah, Okay.
Another bird that preys on these animals is the greater
road runner or Geocossics californian Us. The Greater Roadrunner has
an interesting strategy where it grabs the horned lizard by
(20:34):
a leg or by the tail with its beak, and
then it whips them up in the air and slams
them back down against the ground repeatedly, so it is
beating the lizard against the earth, using centrifugal force to
smash it dead. Basically, it bashes it and bashes it
until it is dead and busted up, and this allows
the roadrunner to take its time orienting the lizard so
(20:57):
it can be swallowed whole head first by attached to
a picture for you of the Greater Roadrunner trying to
get this whole lizard into its mouth head first that
I don't know how this is going to happen. This
is just a photo from the book. It's not animated,
but I believe in you.
Speaker 1 (21:13):
Yeah, yeah, yeah, I mean, roadrunners are such interesting, weird
creatures in their own ride. I don't feel like the
cartoons properly prepared. As for the reality, I've only seen
I've only seen them in the wild, I think one
or two times while I'm in the Arizona. But it's
like it's like seeing like the ghost of a dinosaur
run by. It's pretty neat.
Speaker 3 (21:32):
Yeah yeah yeah. And of course, in the case of
the roadrunner, swallowing it headfirst once again keeps the horns
pointed away from the bird's vital organs. It's going down
the digestive tract.
Speaker 1 (21:43):
Clever girl.
Speaker 3 (21:44):
Yeah yeah, okay, So another bird predator chiwawin ravens or
corvas crypto. Lucas Sherbrook says that these birds, they've got
an interesting difference here. They bring dead horned lizards to
their nests to feed their young, but the ravens render
them safe by not feeding them to their young hole,
(22:05):
but instead ripping them open and only feeding the soft
inerds to the hatchlings, so only guts for the children,
and then the carcass with the hard parts is discarded.
Speaker 1 (22:15):
All right, Well, that's not surprised. Leave it to the
ravens to intelligently dissect before feeding.
Speaker 3 (22:21):
To the end, they're like a tourist at a beach
restaurant picking the meat out of a crab. They're getting
all the juicy bits and not swallowing the hard parts.
Of course, snakes are a major predator of these lizards.
Various species of snakes prey on them, killing them either
with venom or with constriction, and then in all cases
(22:42):
swallowing them whole. Snakes, like birds, do incur some risk
by attempting to swallow a horned lizard. Sometimes the horns
rip them open from the inside, and a crucial factor
seems to be just the relative sizes of the snake
in the lizard. The snake, it's hung, but it can't
get too greedy. It has to know its limits. And
(23:04):
so I guess there are cases where a snake might
be sort of driven near starvation and it's pushing the
boundaries of like, is this thing so big it's going
to kill me to eat it? I'm gonna roll the dice. Now,
that's not all the potential predators of horned lizards, but
I'm going to come back to one more major category
in a minute when we get to the blood squirting.
(23:25):
So there's another interesting framework that Sherbrook introduces in this
chapter where he's talking about the different levels of defense
that a prey animal can deploy when trying to survive
against predators, and the three layers of defense he talks
about are, first of all, avoid being seen second, avoid
(23:47):
being caught, and third be difficult to eat or appear
dangerous to the predator. And you could sort of paraphrase
these as one, hide, two run in three fight. Horned
lizards are not very good at number two. They're not
very good at running away. There are some exceptions, such
(24:08):
as when facing off against certain snakes venomous snakes like
the diamondback rattle snake. Sometimes in facing off against one
of those, the lizard will just run away, But in
most cases it's not going to be great at trying
to outrun predators. They've got kind of short limbs and
awkward movements. So mostly horned lizards excel at number one
(24:31):
and number three avoiding being seen in the first place.
And then if they really if they're cornered and they're
caught and they can't hide anymore, they resist being eaten
somehow by a combination of morphological and behavioral defenses. So
we'll look at number one first, the hiding part. Horned
(24:51):
lizards are masters of camouflage, and Sherbrooke has an interesting
side note about how we often don't appreci cate how
effective a wild animal's camouflage actually is because most people,
you know, if you're not like living out in the wilderness,
most of the time you're going to see any of
these wild animals, it's in some form of media that
(25:16):
is designed to help you see the animals, such as
like a picture in a book or footage in a documentary,
where the whole point is that you're supposed to be
able to see it. And so this kind of we
kind of underappreciate how effective natural camouflage strategies are because
if we were just walking around in the environment, we
(25:36):
likely might go right by animals of this type and
never see them, so we wouldn't even know that we'd
miss them.
Speaker 1 (25:42):
That's a great point. Yeah, And so.
Speaker 3 (25:44):
Horned lizards are very good at hiding. They hide themselves
with a couple of strategies. They hide by disrupting predator
search routines for both shape and color, so their coloration
tends to mimic the patterns of gravelly, sandy or grassy
grounds where they live, and the pigment in their skin
(26:06):
tends to match the color of the local soil or
whatever the background is. So, for example, horned lizards that
live in areas with redder soil will be redder in
color and so forth. Also, in the domain of color,
they have patterns of what is called disruptive coloration. This
is found in many animals where varied color patterns make
it harder to pick out the outline of an object
(26:29):
against the background. This is also one of the main
principles behind human tactical camouflage. Some of their hiding strategies
are more obvious, like in some cases, if there is
a predator around, they might increase their hiddenness by ducking
underneath something so they can run under a shrub or
a rock or some of the ground cover. But another
thing they do often is if a predator is nearby,
(26:51):
they can flatten their bodies against the ground, and this
especially helps protect against, say, the visual detection by birds,
because this flat prevents them from casting a shadow, which
if they did cast a shadow, would reveal their outline.
So if you can't see the outline of the creature,
it disrupts the predator's shape recognition. And the horned lizard's
(27:15):
lateral body spikes also help disrupt shape recognition by interfering
with the casting of a shadow. Now, in order for
a lot of these hiding strategies to be effective, the
horned lizard needs to remain motionless, which it does much
of the time. It pays to be sedentary if you're
one of these buddies, and it also helps that you know,
as ectotherms, they need to spend a lot of time
(27:38):
absorbing sun anyway, because their body temperature is dependent on
the surrounding environment, they don't generate their own body heat
through metabolism. Now, one defensive strategy that Sherbrook talks about,
which in a kind of embarrassing way ping done some
like video game playing styles I'm familiar with, is that
(27:58):
if startled, the horned lizard will often run as fast
as it can a short distance and then suddenly stop
and freeze. Why would it do that? That doesn't seem
to make a lot of sense, but it does actually
if you read it explained. So the lizard usually can't
run very fast very far, but the main purpose of
(28:19):
it seems to be too quickly re enter stealth mode,
so you run a short distance and then freeze in
order to once again blend into the surroundings and hopefully
disappear from the predator's vision. This makes me think of
various I don't know, like Batman, video games and stuff.
Where the bad guys see you and this like, oh oh,
I need to run to the opposite side of the
(28:40):
room and hide, and then they'll all be like where'd
he go?
Speaker 1 (28:43):
Or like a metal gear game where you just immediately
put a box over your body and then they're looking
right at you and maybe they won't see it. Huh.
But you know, I have to say I only have
human eyes. I don't have the eyes of an eagle,
and they're not even great human eyes. But you know,
there have been times where I've been watching an animal
in the wild that is really good at its camouflage,
(29:03):
and you know, either it will be the situation of
looking right at it and not seeing it until there
is movement, or the reverse kind of looking at it
in movement and in the second it stops, I cannot
see it anymore. I know it is there, but I
cannot actually see it. It's just based on the memory
of what just happened.
Speaker 3 (29:23):
So yeah, that's how it works for predators also. I
mean it's again we underappreciate how effective camouflage can be
because we're so trained on this, like media that shows
you this is where it is, look right here. But okay,
(29:47):
let's say all of that has failed. You Your invisibility,
camouflage stealth mode has failed. You're a horned lizard and
you're cornered by a predator that definitely knows you're here.
Here we get to the active defail strategies, where you
try to make yourself look difficult to eat or dangerous
to the predator. Now, the range of behaviors described in
(30:10):
Sherbrook's book here are surprisingly diverse. I wouldn't have expected
this many different things to be on the record, but
Sherbrook lists a number of them, just in response to
the presence of humans. To read from a paragraph here
quote in an almost comic antic, one horned lizard raised
itself high on all four legs, lowered its head, and
(30:33):
in a series of hops, approached its tormentor like a
charging bull. On another occasion, a horned lizard charged and
bit a person's boot. Normally, they do not bite when
captured by hand, but some struggle an attempt to thrust
their horns into the flesh of their captor. Now that's
kind of interesting, though. There are also reports that a
good number of these lizards, if picked up and handled
(30:55):
and sometimes rubbed or stroked, they will become immobile, and
this could be some kind of death feigning strategy, as
seen in some prey animals. You might wonder, like, why
would it be advantageous for a prey animal to pretend
to be dead when it has been gripped by a predator.
There could be different explanations, but I think it's generally
(31:15):
understood that if you pretend to be dead, you can
wait for the predator to relax its grip or focus
in order to have a moment to escape other defensive behaviors.
When cornered, sometimes a horned lizard will inflate its body,
going to puffer fish mode. This will certainly make it
look harder to swallow, and maybe actually be harder to swallow. Remember,
(31:39):
predators can die from eating a horned lizard that is
too big, so you want the predator to be wondering
if you are over the.
Speaker 1 (31:46):
Line look more difficult to eat.
Speaker 3 (31:48):
Another strategy is the backshield thing I talked about earlier.
So you can sometimes flatten your back into a round
shield and then tilt and orient your back towards the predator.
This makes you look big, but also makes you look
difficult to eat. But apparently in other cases they'll do
the opposite. They'll quickly just turn and face a predator
head on. Sometimes they hiss like a snake. This could
(32:11):
be a signal to convey danger and aggression. Sometimes they'll
kind of vibrate their tails. Now, there's some other predator
defense strategy stuff that we might come back to in
part two, but I wanted to get to the blood
squirting here because this is the main event for me.
Sometimes when a horned lizard is threatened, it will blast
a jet of its own blood out of its eyes
(32:33):
toward the attacker. Now, again, Rob, I think you mentioned
this earlier. Not all horned lizard species have been observed
to do this. At the time of Sherbrook's book, he
did say that most species were known to be blood squirters,
the majority, where I think maybe there might be more
different species identified now, so it might not be the
(32:55):
majority at this point.
Speaker 1 (32:56):
I believe that's the case. But what we can look
again at that data before we come back with part
two and clarify if we need to.
Speaker 3 (33:04):
Okay, well, certainly some species do this, Now they don't
do it every time they're threatened. It seems like a
fairly specialized behavior. Sherbroke says that among two species, Texas
horned lizards and regal horned lizards, blood jetting happened during
four to six percent of human captures, so that's not
(33:24):
most of the time. You know, it's like one and
twenty times. It sounds nuts. So it was indeed sometimes
believed to be a myth, but it is real. So
Sherbroke writes that you know, if a lizard is about
to squirt blood out of its eyes, you're going to
see this. In preparation, the lizard arches its back and
it closes its eyes, and the lids around the eyes
(33:48):
become visibly swollen, like you can see that something is
building up there. And then suddenly a thin stream of
blood jets out of one or both eyes, and it
can be shot in either direction, forwards or backwards. This
blood spray can reach a distance of about six feet,
and the jet lasts for about one second per blast,
(34:09):
though the lizard can usually do it again if the
threat persists, so it's not just like one and done.
You can blast more than once six feet.
Speaker 1 (34:19):
That is crazy considering the size of these creatures.
Speaker 3 (34:22):
They're a little things, aren't they. Yeah, so does the
lizard lose a lot of blood from this. Yeah, yeah,
it does, but it usually recovers if it escapes the situation,
so it's not like a lethal amount of blood loss,
but it it does lose a serious amount.
Speaker 1 (34:37):
Better than losing all the blood and the body as well.
Speaker 3 (34:41):
That's right. So research has shown that the horned lizards
are able to do this via a mechanism that rapidly
increases blood pressure in chambers within the head. So the
way it works is that blood flows into the head
via the arteries, but then the lizards have a set
of muscle that they can use to squeeze closed the veins,
(35:04):
leading blood back out of the head. So when they
squeeze these muscles, blood flows into the head but not out,
and excess build up of blood flows into the ocular sinuses.
These are voids within the facial tissue around the eye socket,
and this manifests externally as bulging eyelids. Eventually, the pressure
(35:25):
becomes so great that the capillaries in these sinuses burst.
Blood is rapidly released and escapes through the easiest route
to the surface through the eye and the tear duct
and here you get the blood jets. Now there's a
sentence in Sherbrook's book that I love there's like, oh,
there's such a story behind this, and no description of
(35:48):
what this means. Sherbroke writes, quote, humans sampling the blood
sprayed do not taste anything strongly objectionable.
Speaker 1 (35:58):
That statement raises a number of questions. Who methodology past
history with the sampling of lizard blood? Yeah? And I
mean one of the key questions though that arises from
this is, of course that in a lot of the literature,
the reason cited for the blood spurning is that there
is something objectionable about the taste or sensation of this
(36:20):
creature's blood.
Speaker 3 (36:21):
Well, I think there is, but maybe not perceptible to humans.
So what is the point of the blood squirting? Well,
according to Sherbrook, a clue comes down to the relatively
selective employment of this defensive behavior against only certain predators
we mentioned it only happens in like four to six
percent of human captures. The lizard usually does not squirt
(36:44):
blood out of its eyes at other predators we've mentioned earlier,
like birds, leopard lizards, snakes. So who do they use
it against? Dogs? Wild canids such as the coyote and
the kit fox or Vulpius macro. Any type of dog
attacks a horned lizard, here come the blood jets. When
(37:06):
any of the sprayed blood gets into a dog's mouth.
Sherbroke says that you can usually see the dog showing
obvious displeasure with the taste, like shaking its head back
and forth, sometimes chewing or wiping its mouth on grass,
as if trying to get the taste out of its mouth.
Speaker 1 (37:23):
Oh wow, no, this yeah, this makes a lot of
sense then. I mean, we've talked before about how dogs
their sense of smell and therefore their sense of taste
is just in a realm, so far beyond human levels
of taste and scent that they it's just a different,
a different universe.
Speaker 3 (37:40):
Sherbrook writes, quote, clearly there is some chemical component of
the blood that causes dog family members goosetatory or taste distress.
The blood never harms them, but it certainly suggests to
them that a different meal would be more palatable. How
fortunate for the horned lizard to be able to deliver
that message before war being severely bitten and tasted. And
(38:03):
Sherbrooke notes that there are some other lizards, not horned lizards,
that have occasionally been seen bleeding lightly from the eyes
under stress, and he speculates that perhaps something like this
was an early stage in the evolution of this more
elaborate defensive measure, maybe slight bleeding from the eyes under stress.
(38:26):
And then horned lizard ancestors have blood that is for
some reason distasteful to canids. Sometimes that gross blood makes
a predation attempt stop, and then there's evolutionary incentive to
bleed more and more of it preemptively to make the
predation attempt stop earlier and earlier before major injury has occurred,
(38:46):
until you end up with six foot jets of eyeblood.
Speaker 1 (38:49):
It's like really aggressive free samples in the mall food court. Yes,
but instead of trying to bring certain customers in, you're
trying to convince them this food is not for you. Here,
have a taste.
Speaker 3 (39:01):
But so, why is this blood apparently distasteful to canids
to dogs?
Speaker 1 (39:07):
So it seems like the main hypothesis, based on what
I was looking at, is that it comes down to
what these creatures eat. What the horned lizards eat, they
eat copious amounts of ants, and those ants contain formic acid.
So apparently previously researchers thought that the acidity was more
of a glandular product. But now you know, we understand
(39:28):
that it's the blood, like that's what's shooting out. There's
nothing being added to the blood. The blood in and
of itself is supposed to have this formic acid quality.
Speaker 3 (39:38):
That's right. Sherbrooke makes this point in the book that
it was once thought that maybe there were blands around
the eyes adding something to the blood before it gets
blasted out, but they said no, there's no evidence of that.
Speaker 1 (39:50):
Interesting side note, I've already mentioned another big time ant consumer,
the giant anteater of Central and South America. That is
a creature that cannot produce its own stomach acid apparently
and instead depends on formic acid from its prey. Wow. Yeah,
I didn't know that. Another interesting fact concerning horned lizards
here they apparently don't eat fire ants. Fire Ants are,
(40:12):
of course invasive ants from South America beyond the southern
limits of the horned lizard's range. They often they're really
more of a threat to horned lizards because they can
push out native ant species that the horned lizard depends on,
while also provoking human inhabitants to deploy anti ant measures
that you just don't discriminate. So all of this plays
(40:35):
a role in the habitat loss and decline of various
horned lizard species.
Speaker 3 (40:41):
Yeah, i'd read that as well. Many horned lizard populations
throughout the throughout North America have been in decline in
recent decades. And yeah, fire ants are implicated as part
of the picture for why that's happening.
Speaker 1 (40:55):
A related question that I didn't even think to ask
what I just saw come up when I was searching
around for answers on people ask well, can't we get
some ant eaters and some armadillos in on these fire ants,
as these creatures do eat fire ants. And the answer
there is no, not really, because like an ant eater
eats a lot of ants, but it has to go
(41:15):
in like in quick bursts, because it's not immune to
the bites, and so it's got to get in, like,
you know, eat a bunch of ants and get out
of there before it gets too painful. And they're not
going to finish off a colony like they're not going
to eat it down to the to the queen. You know,
they're not gonna eat it down to the last ant.
It's like a devastating raid, but then they have to
move on, so it's not going to like wipe out
(41:35):
populations necessarily. But yes, it seems like the consumption of
ants is key. And I think we're gonna go ahead
and close out this episode, but we're gonna be back
on Thursday. We're gonna get into various other angles concerning
the horned lizard and also some of the traditions surrounding it,
including again I teased out some Navajo traditions and they're
(42:00):
there is one story we're going to come back to
about the Holy toad who eats ants that give him power.
Whoa which is correct? The research they're looking at you
absolutely correct.
Speaker 3 (42:11):
I can't wait.
Speaker 1 (42:12):
All right, Well, we're going to go and close it out,
but in the meantime, go ahead and write in with
your observations concerning the horned lizard. You've seen them out
in the wild, you've studied them right in. We'd love
to hear from you. We'll come back with part two
on Thursday. Reminder that that's when our core episodes published
Tuesdays and Thursdays every week, and the stuff to blow
(42:33):
your podcast feed where we are primarily a science and
culture podcast. We do a short form episode on Wednesdays,
and on Fridays we do Weird House Cinema. That's when
we set aside most of our serious concerns to just
talk about a weird film.
Speaker 3 (42:47):
Huge thanks 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 topic
for the future, or just to say hello, you can
email us at contact Stuff to Blow Your Mind to
dot com.
Speaker 2 (43:08):
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.
Speaker 1 (43:35):
M
Hey, welcome to Stuff to Blow your Mind. This is
Robert Lamb. Today is Saturday, so we have an older
episode of Stuff to Blow Your Mind to share with
you here. This one was originally published eight thirteen, twenty
twenty four. It is Blood Squirting from the Lizard's Eye,
Part one.
Speaker 2 (00:24):
Welcome to Stuff to Blow Your Mind, production of iHeartRadio.
Speaker 1 (00:34):
Hey, welcome to Stuff to Blow your Mind. My name
is Robert Lamb.
Speaker 3 (00:38):
And I am Joe McCormick. And today on Stuff to
Blow Your Mind, we are going to be talking about
an animal, about the horned lizard or frenosoma, a genus
of lizard native to North America, also known as horned
toads or horny toads. From what I've been reading, I
think the people in the biological sciences prefer the more
(00:58):
accurate lizard, applely because they are certainly not toads, though
there are reasons for calling them toads, mainly that they
look like toads.
Speaker 1 (01:07):
Now, we're going to probably try and stick to horned lizard.
I'm probably going to say horned lizard because I like
using the more antiquated term and it sounds more demonic.
But we also might say, horny toad, horned toad, horn toad,
and so forth.
Speaker 3 (01:22):
Throughout the episode, Horned Lizard makes me think learned lizard.
You know, doesn't it suggest a kind of wisdom?
Speaker 1 (01:29):
Yeah? Yeah, sometimes lizards can appear quite wise, so I
buy that.
Speaker 3 (01:35):
And in fact, you might even think about some of
the species of horned lizards as especially wise or discerning
among the reptile kind, because they, as we get into
later in this episode, they have some anti predator strategies
that really require snap judgment calls about say what type
of predator you're dealing with?
Speaker 1 (01:54):
That's right? And I don't know if we'll get into
it in this episode or the next, but among the Navajo,
among the DNA people, they're sometimes called grandfather, so I
think there is often that vibe of maybe sort of
wisdom and power to them.
Speaker 3 (02:07):
Though I have to admit I did come to this
topic through more base and if you know, us predictable routes.
So my window into talking about horned lizards was the
fact that for sci fi horror nerds like us, it's
alien summer. Would you agree, Rob.
Speaker 1 (02:22):
Oh, yeah, it's been an alien summer for me. We've
been chatting about alien movies and the upcoming alien movie.
So yeah, there's a lot of excitement in the air.
Speaker 3 (02:30):
Yeah, there's a new alien movie coming out in theaters
later this week, Alien Romulus. Of course, there's no guarantee
ahead of time it's going to be good. I don't
think they've even released the critics embargo yet. But I'm
just recklessly letting myself get excited regardless tempering expectations is
for the week.
Speaker 1 (02:47):
That's right, Say yes to Xenomorph and then figure the
rest out later.
Speaker 3 (02:52):
You know, if I'm disappointed, I'm disappointed, It'll be okay.
So we've had Aliens on the brain for a few
months here, and we've covered a couple of Aliens copycat
movies on Weird House Cinema. We'll probably do at least
one more, I think that's right.
Speaker 1 (03:05):
We also had a seven part Monster Fact series on
the various creatures and organisms of the alien universe, with
part seven publishing this week.
Speaker 3 (03:12):
Mm hmm. But so we've got all this excitement running
through us, and I was looking to find some real
world biology to cover that had parallels an alien. We've
already done a lot of topics along these lines in
the past, and the idea of the xenomorph's weaponized blood
took hold. So in the Alien movies if you haven't
seen them, the creature in these movies has extremely potent
(03:37):
acid for blood, which appears to serve as a defense strategy.
So if you cause injury to one of the Xenomorphs,
you are likely to get some of its blood on
yourself or on your critical infrastructure, such as the inside
of your spacecraft hull, and that blood will burn through
bodies and space ships alike. So, as observed by the
(03:58):
characters in the first movie, there's real danger in injuring
the creature. How do you fight it?
Speaker 1 (04:03):
That's right. It's also worth pointing out that there is
at least some acid fluid as projectile in the xenomorph world.
The most, I would say, I guess the key example
would be in nineteen seventy nine's Alien the first film,
as we see that emergent face hugger seem to use
acidic secretions to burn through Caine's helmet in order to
(04:24):
access his face. Now, naturally, given that certain wounds, especially
lethal wounds to a Xenomorph, could result in a jet
of acidic blood, we could easily classify that as a
form of defensive spray, and then in Alien three and
Alien Resurrection, the third and fourth movies in the franchise,
we actually see xenomorphs using an offensive acid spray attack,
(04:46):
And of course this has also been used to various
effects in Alien video games for ranged enemies, as well
as in Alien comic books and so forth. Also worth
pointing out that, given our current Mortal Kombat discussions on
Weird House Cinema, the acid spit is one of the
signature moves of the green clad Ninja reptile.
Speaker 3 (05:05):
Is it really a spit because the animation looks to
me more like projectile vomit.
Speaker 1 (05:10):
I think it depends. At least in the first game.
He was in Mortal Kombat too, he would definitely spit.
It was like a kind of a sound over and
over again, and I think it got a little more
vomity later on.
Speaker 3 (05:22):
Okay, Now, of course, it's fairly common in the natural
world to find animals that produce some kind of toxic
defensive fluid that they use to protect themselves against predators
or attack prey. But what seemed less common, though perhaps
more common than you would think, was that the defensive
fluid in question was actually the animal's own blood.
Speaker 1 (05:46):
That's right, because a part of the logic here, of course,
is we tend to think vampire like when we think
about an organism's blood. Right, it's part of the prize,
it's part of the predator's claim. So broadly speaking, it would,
on the surface anyway, seem illogical to think that a
predator could be harmed by blood of its prey.
Speaker 3 (06:01):
But here is where the horned lizard comes in. If
you know one thing about the horned lizard, it is
probably that these various species of lizards have a defensive
adaptation of squirting blood out of their eyes.
Speaker 1 (06:16):
That's right. They're kind of Internet famous for this, a
lot of clips, a lot of a lot of animations
and videos. I should also add that if you know
one thing, you should probably know two things. Also, that
there to some extent horned up, right, because right, I
call them horned lizards, right.
Speaker 3 (06:33):
But while lots of animals are spiky or horned in
some way, I would say that the blood squirting out
of the eyes is such a shocking behavior, such a
bizarre and seemingly rare adaptation, that you would almost have
to wonder if it's not real, Like, is that something
people just made up or does that really happen? And
(06:54):
according to the author of a book that I'm going
to cite in this episode, reports of it have sometimes
in the past been dismissed as tall tales, but they're
not tall tales. The Horned Blizzard's weaponized blood is absolutely real,
and it is the subject of some interesting scientific investigation.
Speaker 1 (07:11):
So this is going to be really fun to get
into now. When we were doing our pre research, though, Joe,
you brought up a resource that we've looked to in
the past, and that's the California herbs dot com website
where they have a wonderful I mean it's not just
about this, but they have a huge listing of various
herp appearances in various films, many of which are very
(07:33):
much in the domain of weird house cinema meaning reptiles, yes, yeah, yeah,
for herpetologist cinema files. And they have a list there
that you shared with me of horned lozerds in movies,
and there are a few that I was familiar with,
you know, because they're pretty popular films. I think what
outlot Josie Wales is on there.
Speaker 3 (07:54):
Yeah, but they they are apparently a number of you know,
westerns I guess where there are horned lizards, which makes
sense because you know, you find a lot of these
several of these species are very common in the American Southwest.
Speaker 1 (08:10):
But also Jodroowski's Holy Mountain is included there, his film
from nineteen seventy three that does have a very memorable
hert scene, though it may contain shots of actual hurts
being exploded with fireworks, so you know, go into that
one with a certain amount of caution. But it's I mean,
it's Holy Mountains, so I'd advise a great deal of
content consideration before you watch it. Anyway, It's kind of
(08:32):
a titan of surreal cinema and an important film when
you're looking at weird psychotronic pictures and you know, Mexican
cinema certainly cinema of the nineteen seventies. But it is
not for everyone.
Speaker 3 (08:43):
Yeah, that's not movie Night with the grandparents.
Speaker 1 (08:46):
Yeah, I believe the scene in question. It's been a
long time since I've seen it, and I have only
seen it like used to. The only way you could
watch it would be like a rip of a Japanese
laser disc, and they're much better sources for it available now,
But there is an extended scene where the conquest of
Mexico is recreated with frogs and toads and lizards standing
(09:08):
in for the various actors and sides in this conflict.
Speaker 3 (09:13):
I did not remember that detail. There's a lot I've
forgotten about Holy Mountain.
Speaker 1 (09:17):
So I would say cameo appearance by the horned lizard. Now,
it's worth noting at the top here that we're not
dealing with a single species when we're discussing horned lizards,
but rather an entire genus of North American lizards, and
that's Phinosoma, including some twenty one species which range as
far north as parts of Canada and on the southern
end range all the way through Mexico and into Guatemala.
(09:39):
And of these again, somewhere around twenty one species, at
least eight species squirt blood from the eye region. So
just an example of range here, there's the greater short
horned lizard or Hernandez is short horned lizard, and it
can be found as far north as southern Saskatchewan and
Alberta and south into the Texas Panhandle in central Mexico.
(10:00):
And this is one of the species of bloodshooters.
Speaker 3 (10:03):
Yeah, that's right. But as you said, Rob, the various
species of horned lizards can be found all over the
part of North America, from down in southern Mexico all
the way up to the southern part of Canada. And
you can look up maps that show you sort of
different estimated ranges of the different species. But yeah, you'll
find them all throughout the arid and semi arid regions
(10:26):
of the North American West. Here, I think it would
be a good place to introduce one of my major
sources for this episode, which is a book called Introduction
to Horned Lizards of North America by Wade C. Sherbrook.
This was published by University of California Press in two
thousand and three, and the author, Wade Sherbrooke, was director
(10:46):
of the Southwestern Research Station of the American Museum of
Natural History, and so one of the questions Sherbrooke addresses
in the introduction of this book is why are horned
lizards commonly referred to as toads, horned toads, horny toads. Well,
they really do kind of look like toads. They tend
(11:07):
to have a wide body when viewed from above, especially
in certain defensive postures where they sort of flatten and
widen their bodies out to create to sort of turn
their backs into a shield. They tend to for lizards
have a short, blunt snout which can resemble a toad's head,
and they also have an awkward walking gait. They tend
(11:30):
to have a camouflaged appearance which helps them blend into
their often sandy or gravelly surroundings, and this can resemble
the model color patterns and bumpy texture you would see
on the backs of some toads, so in lots of
different ways they look like toads, and this led to
the name of their genus. Frinosoma means toad body, phrenoss
(11:50):
toad and soma of course means body, toad body, total
toad body to add to the toad comparisons to make
them even more of a toad body. Can observe how
they eat. Now, the different species of horned lizards have
some different different diets. Some are more sort of taking
what they can get than others, but some are quite
(12:12):
specialized to eating insects and specifically ants, specifically even more
harvester ants. And if you watch the horned lizards eat
harvester ants. When they specialize in this food source, they
have a kind of a sticky, flicking tongue action, much
like we associate with toads and frogs. I was reading
(12:33):
in one part of the Sherbrook book about how exactly
it is that these horned lizards can eat these incredibly
venomous ants, and apparently they have a strategy of like
flicking them into the mouth, and then as they swallow
the ant, the ant becomes covered in this layer of
mucus that comes out of glands in the lizard's throat,
(12:55):
and this coating of mucus surrounds the ant as the
ant is is digested and essentially disables it from biting
or stinging the lizard from the inside until it is
well dead and able to be digested. And these lizards
have to eat a lot of these ants because ants
are not super nutritious like they've got There's not a
(13:17):
lot of meat on that bone. It's mostly bone.
Speaker 1 (13:20):
That's right. Like For instance, one of the other big
ant eaters out there is of course the mammalian ant eater,
and they are known to eat tons of ants and termites.
I've seen estimates of like thirty thousand ants and termites
a day, But even that is still a low calorie diet,
and it's one of the reasons that we think that
ant eaters have one of the lowest mammalian body temperatures.
(13:40):
But in terms of the the what we're dealing with here,
the horned lizards consumption of ants, I found an interesting
article that answers the question, well, how do they eat
them safely? This was from two thousand and eight published
in the journal jazz A by Sherbrooke and Schwink, And
the answer is in the title Horned lizards Incapacity Dangerous
ant prey with mucus. And we've already touched on the
(14:03):
main aspect of this, but they provide one more little
detail that I really like. They write, quote, we show
that they're derived feeding kind of mattics that are associated
with unique mucus secreting hyrngel papilia that apparently serve to
immobilize and incapacitate dangerous ants as they are swallowed by
compacting them and binding them in mucus trans And then
(14:25):
they later add the detail ants extracted from fresh killed
horned lizard's stomachs are curled ventrally into balls and bound
in mucus.
Speaker 3 (14:35):
Take an ant as you're swallowing it, coat it with slime,
and wadd it up into a ball so that you
can digest it without it getting into trouble inside your
digestive tract. That's right, Roll them up, all right, So
(14:58):
that is horned lizards as predators. But I wanted to
focus for the majority of today's episode on horned lizards
as prey because it is, of course in their role
as prey and in their anti predator defense strategies that
we see the jets of blood emerge from the eyes.
So here I want to go back to that book
I mentioned by Wade Sherbrook. He has an excellent section
(15:20):
in this book called Enemies and Defense, which sort of
covers a nearly comprehensive list of different sort of predator
prey relationships between horned lizard species and the predators that
target them, and the strategies they have for resisting these predators. So,
as we alluded to earlier, horned lizards are of course
(15:43):
covered in spikes and scales. This is a pretty sophisticated
armor defense. If you've never seen what a horned lizard
looks like by the way, you should look one up.
I mean, first of all, they are beautiful, but this
will give you a better idea of what we're talking
about as we continually reference the armour moving on. They
tend to have spikes and scales along different parts of
(16:05):
their bodies, such as sort of spiky flank protrusions running
down the lateral sides of the body, but then also
sometimes some kind of bumpy or tough coverings on the back,
and then especially bony spike protrusions around the crown of
the head. So some of the spiky looking things, usually
the smaller ones are just more modified scales, but the
(16:29):
spikes around the head are actually like hard, sharp bony
spikes now covered in spikes and scales. As they are,
you might not think that a horned lizard would look
very appetizing, but you know, out here in the arid
and semi arid regions of the American West, many predators
will take whatever they can get, and so horned lizards
(16:49):
are indeed a prey animal to many species of predators.
Juveniles are the most vulnerable to predation. They're smaller and
they have less developed armor, so many are eaten between
the time they hatch from their eggs and the first hibernation.
But Sherbrooke in this chapter gets into a list of
different predators, and the first one I want to look
(17:10):
at is his section on the long nosed leopard lizard
or the Gambelia whizly zennii. These are worth looking up
a picture of as well, because while they're not very
interesting in terms of shape, they're just sort of like
larger looking predatory lizards. They do have a truly leopard
looking coloration pattern.
Speaker 1 (17:31):
Yeah. Yeah, they're quite quite fetching in their own right.
Speaker 3 (17:33):
So these lizards will frequently attack and eat horned lizards,
especially juveniles, and the general strategy here is not super complicated.
It is to bite them near the head and then
swallow them whole head first. You know, this is just
me reasoning from the pictures, but the sort of backwards
pointing orientation of the head spikes, because they sort of
(17:55):
extend backward from the head like a crown, it makes
it seem like it would probably be easier to swallow
a horned lizard head first rather than tail first, Like
if you went backwards, I would think the spikes would
would be more likely to catch like hooks in the
lining of the throat and the digestive system. But it
also seems like eating one of these things head first
(18:16):
would be a very no going back scenario. You know,
once you start eating a big one, you're committed.
Speaker 1 (18:21):
Yeah, yeah, you can't put it in reverse.
Speaker 3 (18:24):
Sherbrook says in the book about defensive strategies that when
attacked by a leopard lizard a horned lizard, and again,
defensive strategy is very somewhat by species, so we'll be
speaking in some generalities here, but the horned lizard will
often try to defend itself by flattening out its back
into a wide shield shape so it wants to look
(18:46):
as wide as possible, and then tilting and orienting its
armored shield back toward the predator. And again, adults with
well developed armor are much less vulnerable to leopard lizards.
The next category is birds. A number of different birds
prey on horned lizards. Sherbroke mentions hawks such as the
(19:07):
red shouldered hawk or buteolineatis, but also smaller birds like
the prairie falcon, the American kestrel, and the loggerhead shrike.
Predatory birds with powerful talons and beaks have an advantage
when preying on these lizards because they have the ability
to tear the lizard apart and eat it piece by piece,
(19:30):
making it a somewhat easier proposition to consume that this
spiky animal as opposed to an armored adult that needs
to be swallowed whole. However, it does still come with risks.
Sherbrooke mentions one case of a red shouldered hawk that
was found dead after having eaten a couple of Texas
horned lizards. Apparently one of the horns had pierced through
(19:52):
the hawk's throat from the inside. Oh, and I can't
help but apply like a human level of grossed out
to this. Like I know it's just part of the
you know, their way of making a living, but I
cannot imagine eating something this spiky.
Speaker 1 (20:09):
And it's like a like a like a wheat then,
except even worse right.
Speaker 3 (20:14):
Yeah, Oh, it's like you know, you ever think when
you're like eating a tortilla chip and you don't chew
it upright and you get a shard caught in your throat. Yeah, Okay.
Another bird that preys on these animals is the greater
road runner or Geocossics californian Us. The Greater Roadrunner has
an interesting strategy where it grabs the horned lizard by
(20:34):
a leg or by the tail with its beak, and
then it whips them up in the air and slams
them back down against the ground repeatedly, so it is
beating the lizard against the earth, using centrifugal force to
smash it dead. Basically, it bashes it and bashes it
until it is dead and busted up, and this allows
the roadrunner to take its time orienting the lizard so
(20:57):
it can be swallowed whole head first by attached to
a picture for you of the Greater Roadrunner trying to
get this whole lizard into its mouth head first that
I don't know how this is going to happen. This
is just a photo from the book. It's not animated,
but I believe in you.
Speaker 1 (21:13):
Yeah, yeah, yeah, I mean, roadrunners are such interesting, weird
creatures in their own ride. I don't feel like the
cartoons properly prepared. As for the reality, I've only seen
I've only seen them in the wild, I think one
or two times while I'm in the Arizona. But it's
like it's like seeing like the ghost of a dinosaur
run by. It's pretty neat.
Speaker 3 (21:32):
Yeah yeah yeah. And of course, in the case of
the roadrunner, swallowing it headfirst once again keeps the horns
pointed away from the bird's vital organs. It's going down
the digestive tract.
Speaker 1 (21:43):
Clever girl.
Speaker 3 (21:44):
Yeah yeah, okay, So another bird predator chiwawin ravens or
corvas crypto. Lucas Sherbrook says that these birds, they've got
an interesting difference here. They bring dead horned lizards to
their nests to feed their young, but the ravens render
them safe by not feeding them to their young hole,
(22:05):
but instead ripping them open and only feeding the soft
inerds to the hatchlings, so only guts for the children,
and then the carcass with the hard parts is discarded.
Speaker 1 (22:15):
All right, Well, that's not surprised. Leave it to the
ravens to intelligently dissect before feeding.
Speaker 3 (22:21):
To the end, they're like a tourist at a beach
restaurant picking the meat out of a crab. They're getting
all the juicy bits and not swallowing the hard parts.
Of course, snakes are a major predator of these lizards.
Various species of snakes prey on them, killing them either
with venom or with constriction, and then in all cases
(22:42):
swallowing them whole. Snakes, like birds, do incur some risk
by attempting to swallow a horned lizard. Sometimes the horns
rip them open from the inside, and a crucial factor
seems to be just the relative sizes of the snake
in the lizard. The snake, it's hung, but it can't
get too greedy. It has to know its limits. And
(23:04):
so I guess there are cases where a snake might
be sort of driven near starvation and it's pushing the
boundaries of like, is this thing so big it's going
to kill me to eat it? I'm gonna roll the dice. Now,
that's not all the potential predators of horned lizards, but
I'm going to come back to one more major category
in a minute when we get to the blood squirting.
(23:25):
So there's another interesting framework that Sherbrook introduces in this
chapter where he's talking about the different levels of defense
that a prey animal can deploy when trying to survive
against predators, and the three layers of defense he talks
about are, first of all, avoid being seen second, avoid
(23:47):
being caught, and third be difficult to eat or appear
dangerous to the predator. And you could sort of paraphrase
these as one, hide, two run in three fight. Horned
lizards are not very good at number two. They're not
very good at running away. There are some exceptions, such
(24:08):
as when facing off against certain snakes venomous snakes like
the diamondback rattle snake. Sometimes in facing off against one
of those, the lizard will just run away, But in
most cases it's not going to be great at trying
to outrun predators. They've got kind of short limbs and
awkward movements. So mostly horned lizards excel at number one
(24:31):
and number three avoiding being seen in the first place.
And then if they really if they're cornered and they're
caught and they can't hide anymore, they resist being eaten
somehow by a combination of morphological and behavioral defenses. So
we'll look at number one first, the hiding part. Horned
(24:51):
lizards are masters of camouflage, and Sherbrooke has an interesting
side note about how we often don't appreci cate how
effective a wild animal's camouflage actually is because most people,
you know, if you're not like living out in the wilderness,
most of the time you're going to see any of
these wild animals, it's in some form of media that
(25:16):
is designed to help you see the animals, such as
like a picture in a book or footage in a documentary,
where the whole point is that you're supposed to be
able to see it. And so this kind of we
kind of underappreciate how effective natural camouflage strategies are because
if we were just walking around in the environment, we
(25:36):
likely might go right by animals of this type and
never see them, so we wouldn't even know that we'd
miss them.
Speaker 1 (25:42):
That's a great point. Yeah, And so.
Speaker 3 (25:44):
Horned lizards are very good at hiding. They hide themselves
with a couple of strategies. They hide by disrupting predator
search routines for both shape and color, so their coloration
tends to mimic the patterns of gravelly, sandy or grassy
grounds where they live, and the pigment in their skin
(26:06):
tends to match the color of the local soil or
whatever the background is. So, for example, horned lizards that
live in areas with redder soil will be redder in
color and so forth. Also, in the domain of color,
they have patterns of what is called disruptive coloration. This
is found in many animals where varied color patterns make
it harder to pick out the outline of an object
(26:29):
against the background. This is also one of the main
principles behind human tactical camouflage. Some of their hiding strategies
are more obvious, like in some cases, if there is
a predator around, they might increase their hiddenness by ducking
underneath something so they can run under a shrub or
a rock or some of the ground cover. But another
thing they do often is if a predator is nearby,
(26:51):
they can flatten their bodies against the ground, and this
especially helps protect against, say, the visual detection by birds,
because this flat prevents them from casting a shadow, which
if they did cast a shadow, would reveal their outline.
So if you can't see the outline of the creature,
it disrupts the predator's shape recognition. And the horned lizard's
(27:15):
lateral body spikes also help disrupt shape recognition by interfering
with the casting of a shadow. Now, in order for
a lot of these hiding strategies to be effective, the
horned lizard needs to remain motionless, which it does much
of the time. It pays to be sedentary if you're
one of these buddies, and it also helps that you know,
as ectotherms, they need to spend a lot of time
(27:38):
absorbing sun anyway, because their body temperature is dependent on
the surrounding environment, they don't generate their own body heat
through metabolism. Now, one defensive strategy that Sherbrook talks about,
which in a kind of embarrassing way ping done some
like video game playing styles I'm familiar with, is that
(27:58):
if startled, the horned lizard will often run as fast
as it can a short distance and then suddenly stop
and freeze. Why would it do that? That doesn't seem
to make a lot of sense, but it does actually
if you read it explained. So the lizard usually can't
run very fast very far, but the main purpose of
(28:19):
it seems to be too quickly re enter stealth mode,
so you run a short distance and then freeze in
order to once again blend into the surroundings and hopefully
disappear from the predator's vision. This makes me think of
various I don't know, like Batman, video games and stuff.
Where the bad guys see you and this like, oh oh,
I need to run to the opposite side of the
(28:40):
room and hide, and then they'll all be like where'd
he go?
Speaker 1 (28:43):
Or like a metal gear game where you just immediately
put a box over your body and then they're looking
right at you and maybe they won't see it. Huh.
But you know, I have to say I only have
human eyes. I don't have the eyes of an eagle,
and they're not even great human eyes. But you know,
there have been times where I've been watching an animal
in the wild that is really good at its camouflage,
(29:03):
and you know, either it will be the situation of
looking right at it and not seeing it until there
is movement, or the reverse kind of looking at it
in movement and in the second it stops, I cannot
see it anymore. I know it is there, but I
cannot actually see it. It's just based on the memory
of what just happened.
Speaker 3 (29:23):
So yeah, that's how it works for predators also. I
mean it's again we underappreciate how effective camouflage can be
because we're so trained on this, like media that shows
you this is where it is, look right here. But okay,
(29:47):
let's say all of that has failed. You Your invisibility,
camouflage stealth mode has failed. You're a horned lizard and
you're cornered by a predator that definitely knows you're here.
Here we get to the active defail strategies, where you
try to make yourself look difficult to eat or dangerous
to the predator. Now, the range of behaviors described in
(30:10):
Sherbrook's book here are surprisingly diverse. I wouldn't have expected
this many different things to be on the record, but
Sherbrook lists a number of them, just in response to
the presence of humans. To read from a paragraph here
quote in an almost comic antic, one horned lizard raised
itself high on all four legs, lowered its head, and
(30:33):
in a series of hops, approached its tormentor like a
charging bull. On another occasion, a horned lizard charged and
bit a person's boot. Normally, they do not bite when
captured by hand, but some struggle an attempt to thrust
their horns into the flesh of their captor. Now that's
kind of interesting, though. There are also reports that a
good number of these lizards, if picked up and handled
(30:55):
and sometimes rubbed or stroked, they will become immobile, and
this could be some kind of death feigning strategy, as
seen in some prey animals. You might wonder, like, why
would it be advantageous for a prey animal to pretend
to be dead when it has been gripped by a predator.
There could be different explanations, but I think it's generally
(31:15):
understood that if you pretend to be dead, you can
wait for the predator to relax its grip or focus
in order to have a moment to escape other defensive behaviors.
When cornered, sometimes a horned lizard will inflate its body,
going to puffer fish mode. This will certainly make it
look harder to swallow, and maybe actually be harder to swallow. Remember,
(31:39):
predators can die from eating a horned lizard that is
too big, so you want the predator to be wondering
if you are over the.
Speaker 1 (31:46):
Line look more difficult to eat.
Speaker 3 (31:48):
Another strategy is the backshield thing I talked about earlier.
So you can sometimes flatten your back into a round
shield and then tilt and orient your back towards the predator.
This makes you look big, but also makes you look
difficult to eat. But apparently in other cases they'll do
the opposite. They'll quickly just turn and face a predator
head on. Sometimes they hiss like a snake. This could
(32:11):
be a signal to convey danger and aggression. Sometimes they'll
kind of vibrate their tails. Now, there's some other predator
defense strategy stuff that we might come back to in
part two, but I wanted to get to the blood
squirting here because this is the main event for me.
Sometimes when a horned lizard is threatened, it will blast
a jet of its own blood out of its eyes
(32:33):
toward the attacker. Now, again, Rob, I think you mentioned
this earlier. Not all horned lizard species have been observed
to do this. At the time of Sherbrook's book, he
did say that most species were known to be blood squirters,
the majority, where I think maybe there might be more
different species identified now, so it might not be the
(32:55):
majority at this point.
Speaker 1 (32:56):
I believe that's the case. But what we can look
again at that data before we come back with part
two and clarify if we need to.
Speaker 3 (33:04):
Okay, well, certainly some species do this, Now they don't
do it every time they're threatened. It seems like a
fairly specialized behavior. Sherbroke says that among two species, Texas
horned lizards and regal horned lizards, blood jetting happened during
four to six percent of human captures, so that's not
(33:24):
most of the time. You know, it's like one and
twenty times. It sounds nuts. So it was indeed sometimes
believed to be a myth, but it is real. So
Sherbroke writes that you know, if a lizard is about
to squirt blood out of its eyes, you're going to
see this. In preparation, the lizard arches its back and
it closes its eyes, and the lids around the eyes
(33:48):
become visibly swollen, like you can see that something is
building up there. And then suddenly a thin stream of
blood jets out of one or both eyes, and it
can be shot in either direction, forwards or backwards. This
blood spray can reach a distance of about six feet,
and the jet lasts for about one second per blast,
(34:09):
though the lizard can usually do it again if the
threat persists, so it's not just like one and done.
You can blast more than once six feet.
Speaker 1 (34:19):
That is crazy considering the size of these creatures.
Speaker 3 (34:22):
They're a little things, aren't they. Yeah, so does the
lizard lose a lot of blood from this. Yeah, yeah,
it does, but it usually recovers if it escapes the situation,
so it's not like a lethal amount of blood loss,
but it it does lose a serious amount.
Speaker 1 (34:37):
Better than losing all the blood and the body as well.
Speaker 3 (34:41):
That's right. So research has shown that the horned lizards
are able to do this via a mechanism that rapidly
increases blood pressure in chambers within the head. So the
way it works is that blood flows into the head
via the arteries, but then the lizards have a set
of muscle that they can use to squeeze closed the veins,
(35:04):
leading blood back out of the head. So when they
squeeze these muscles, blood flows into the head but not out,
and excess build up of blood flows into the ocular sinuses.
These are voids within the facial tissue around the eye socket,
and this manifests externally as bulging eyelids. Eventually, the pressure
(35:25):
becomes so great that the capillaries in these sinuses burst.
Blood is rapidly released and escapes through the easiest route
to the surface through the eye and the tear duct
and here you get the blood jets. Now there's a
sentence in Sherbrook's book that I love there's like, oh,
there's such a story behind this, and no description of
(35:48):
what this means. Sherbroke writes, quote, humans sampling the blood
sprayed do not taste anything strongly objectionable.
Speaker 1 (35:58):
That statement raises a number of questions. Who methodology past
history with the sampling of lizard blood? Yeah? And I
mean one of the key questions though that arises from
this is, of course that in a lot of the literature,
the reason cited for the blood spurning is that there
is something objectionable about the taste or sensation of this
(36:20):
creature's blood.
Speaker 3 (36:21):
Well, I think there is, but maybe not perceptible to humans.
So what is the point of the blood squirting? Well,
according to Sherbrook, a clue comes down to the relatively
selective employment of this defensive behavior against only certain predators
we mentioned it only happens in like four to six
percent of human captures. The lizard usually does not squirt
(36:44):
blood out of its eyes at other predators we've mentioned earlier,
like birds, leopard lizards, snakes. So who do they use
it against? Dogs? Wild canids such as the coyote and
the kit fox or Vulpius macro. Any type of dog
attacks a horned lizard, here come the blood jets. When
(37:06):
any of the sprayed blood gets into a dog's mouth.
Sherbroke says that you can usually see the dog showing
obvious displeasure with the taste, like shaking its head back
and forth, sometimes chewing or wiping its mouth on grass,
as if trying to get the taste out of its mouth.
Speaker 1 (37:23):
Oh wow, no, this yeah, this makes a lot of
sense then. I mean, we've talked before about how dogs
their sense of smell and therefore their sense of taste
is just in a realm, so far beyond human levels
of taste and scent that they it's just a different,
a different universe.
Speaker 3 (37:40):
Sherbrook writes, quote, clearly there is some chemical component of
the blood that causes dog family members goosetatory or taste distress.
The blood never harms them, but it certainly suggests to
them that a different meal would be more palatable. How
fortunate for the horned lizard to be able to deliver
that message before war being severely bitten and tasted. And
(38:03):
Sherbrooke notes that there are some other lizards, not horned lizards,
that have occasionally been seen bleeding lightly from the eyes
under stress, and he speculates that perhaps something like this
was an early stage in the evolution of this more
elaborate defensive measure, maybe slight bleeding from the eyes under stress.
(38:26):
And then horned lizard ancestors have blood that is for
some reason distasteful to canids. Sometimes that gross blood makes
a predation attempt stop, and then there's evolutionary incentive to
bleed more and more of it preemptively to make the
predation attempt stop earlier and earlier before major injury has occurred,
(38:46):
until you end up with six foot jets of eyeblood.
Speaker 1 (38:49):
It's like really aggressive free samples in the mall food court. Yes,
but instead of trying to bring certain customers in, you're
trying to convince them this food is not for you. Here,
have a taste.
Speaker 3 (39:01):
But so, why is this blood apparently distasteful to canids
to dogs?
Speaker 1 (39:07):
So it seems like the main hypothesis, based on what
I was looking at, is that it comes down to
what these creatures eat. What the horned lizards eat, they
eat copious amounts of ants, and those ants contain formic acid.
So apparently previously researchers thought that the acidity was more
of a glandular product. But now you know, we understand
(39:28):
that it's the blood, like that's what's shooting out. There's
nothing being added to the blood. The blood in and
of itself is supposed to have this formic acid quality.
Speaker 3 (39:38):
That's right. Sherbrooke makes this point in the book that
it was once thought that maybe there were blands around
the eyes adding something to the blood before it gets
blasted out, but they said no, there's no evidence of that.
Speaker 1 (39:50):
Interesting side note, I've already mentioned another big time ant consumer,
the giant anteater of Central and South America. That is
a creature that cannot produce its own stomach acid apparently
and instead depends on formic acid from its prey. Wow. Yeah,
I didn't know that. Another interesting fact concerning horned lizards
here they apparently don't eat fire ants. Fire Ants are,
(40:12):
of course invasive ants from South America beyond the southern
limits of the horned lizard's range. They often they're really
more of a threat to horned lizards because they can
push out native ant species that the horned lizard depends on,
while also provoking human inhabitants to deploy anti ant measures
that you just don't discriminate. So all of this plays
(40:35):
a role in the habitat loss and decline of various
horned lizard species.
Speaker 3 (40:41):
Yeah, i'd read that as well. Many horned lizard populations
throughout the throughout North America have been in decline in
recent decades. And yeah, fire ants are implicated as part
of the picture for why that's happening.
Speaker 1 (40:55):
A related question that I didn't even think to ask
what I just saw come up when I was searching
around for answers on people ask well, can't we get
some ant eaters and some armadillos in on these fire ants,
as these creatures do eat fire ants. And the answer
there is no, not really, because like an ant eater
eats a lot of ants, but it has to go
(41:15):
in like in quick bursts, because it's not immune to
the bites, and so it's got to get in, like,
you know, eat a bunch of ants and get out
of there before it gets too painful. And they're not
going to finish off a colony like they're not going
to eat it down to the to the queen. You know,
they're not gonna eat it down to the last ant.
It's like a devastating raid, but then they have to
move on, so it's not going to like wipe out
(41:35):
populations necessarily. But yes, it seems like the consumption of
ants is key. And I think we're gonna go ahead
and close out this episode, but we're gonna be back
on Thursday. We're gonna get into various other angles concerning
the horned lizard and also some of the traditions surrounding it,
including again I teased out some Navajo traditions and they're
(42:00):
there is one story we're going to come back to
about the Holy toad who eats ants that give him power.
Whoa which is correct? The research they're looking at you
absolutely correct.
Speaker 3 (42:11):
I can't wait.
Speaker 1 (42:12):
All right, Well, we're going to go and close it out,
but in the meantime, go ahead and write in with
your observations concerning the horned lizard. You've seen them out
in the wild, you've studied them right in. We'd love
to hear from you. We'll come back with part two
on Thursday. Reminder that that's when our core episodes published
Tuesdays and Thursdays every week, and the stuff to blow
(42:33):
your podcast feed where we are primarily a science and
culture podcast. We do a short form episode on Wednesdays,
and on Fridays we do Weird House Cinema. That's when
we set aside most of our serious concerns to just
talk about a weird film.
Speaker 3 (42:47):
Huge thanks 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 topic
for the future, or just to say hello, you can
email us at contact Stuff to Blow Your Mind to
dot com.
Speaker 2 (43:08):
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.
Speaker 1 (43:35):
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On Purpose with Jay Shetty
I’m Jay Shetty host of On Purpose the worlds #1 Mental Health podcast and I’m so grateful you found us. I started this podcast 5 years ago to invite you into conversations and workshops that are designed to help make you happier, healthier and more healed. I believe that when you (yes you) feel seen, heard and understood you’re able to deal with relationship struggles, work challenges and life’s ups and downs with more ease and grace. I interview experts, celebrities, thought leaders and athletes so that we can grow our mindset, build better habits and uncover a side of them we’ve never seen before. New episodes every Monday and Friday. Your support means the world to me and I don’t take it for granted — click the follow button and leave a review to help us spread the love with On Purpose. I can’t wait for you to listen to your first or 500th episode!