August 13, 2024 • 43 mins
In this 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.
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Episode Transcript
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Speaker 1 (00:03):
Welcome to Stuff to Blow Your Mind production of iHeartRadio.
Speaker 2 (00:12):
Hey, welcome to Stuff to Blow Your Mind. My name
is Robert.
Speaker 3 (00:15):
Lamb 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
(00:36):
more accurate lizard appellation because they are certainly not toads,
though there are reasons for calling them toads, mainly that
they look like toads.
Speaker 2 (00:46):
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. Throughout the episode.
Speaker 3 (01:02):
Horned Lizard makes me think learned lizard. You know, doesn't
it suggest a kind of wisdom?
Speaker 2 (01:08):
Yeah? Yeah, sometimes lizards can appear quite wise, so I buy.
Speaker 3 (01:13):
That, 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 2 (01:32):
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 Dne 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 (01:45):
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 have.
Speaker 2 (02:00):
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 (02:09):
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 2 (02:25):
That's right, Say yes to Xenomorph and then figure the
rest out later.
Speaker 3 (02:30):
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 2 (02:43):
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 (02:51):
M 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 in a and
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
(03:14):
potent 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
(03:36):
by the characters in the first movie, there's real danger
in injuring the creature. How do you fight it?
Speaker 2 (03:42):
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
(04:03):
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,
(04:25):
And of course this has also been used to various
effect 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 (04:43):
Is it really a spit because the animation looks to
me more like projectile vomit.
Speaker 2 (04:49):
I think it depends. At least in the first game.
He was in Mortal Kombat too, he would definitely spit.
I don't. It was like a kind of a sound
over and over again, and I think it got a
little more vomity later.
Speaker 3 (05:00):
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 2 (05:24):
That's right, because 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 the blood of its prey.
Speaker 3 (05:39):
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 2 (05:55):
That's right. They're kind of internet famous for this, a
lot of clips, a lot of animations and videos. I
should also add that if you know one thing, you
should probably know two things. Also, that they're to some
extent horned up right, because right, tall them horned lizards, right.
Speaker 3 (06:12):
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
(06:32):
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 horn Blizzard's weaponized blood is absolutely
real and it is the subject of some interesting scientific investigation.
Speaker 2 (06:49):
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
(07:11):
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 lizards in movies,
and there are a few that I was familiar with,
you know, because they're pretty popular films. I think what
Outlaw Josie Wales is on there.
Speaker 3 (07:33):
Yeah, yeah, but the wldye there 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 2 (07:48):
But also Jo Roowski'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
herbs 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 a it's
(08:11):
kind of 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.
Speaker 3 (08:20):
But it is not for everyone. Yeah, that's not movie
Night with the grandparents.
Speaker 2 (08:25):
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 like frogs and toads and lizards
(08:47):
standing in for the various actors and sides in this conflict.
Speaker 3 (08:51):
I did not remember that detail there's a lot I've
forgotten about Holy Mountain.
Speaker 2 (08:55):
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.
(09:17):
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.
(09:39):
And this is one of the species of bloodshooters.
Speaker 3 (09:42):
Yeah, that's right. But as you said, Rob, the various
species of horned lizards can be found all over the
western part of North America, from down to 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
(10:04):
regions 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
(10:25):
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
(10:46):
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 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
(11:08):
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 phrenos
(11:28):
as 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. You can
observe how they eat. Now. The different species of horned
lizards have some different different diets. Some are more taking
what they can get than others, but some are quite
(11:51):
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
(12:12):
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,
(12:34):
and this coating of mucus surrounds the ant as the
ant 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 lot
(12:56):
of meat on that bone. It's mostly bone.
Speaker 2 (12:58):
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,
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. But
(13:19):
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 incapacitate dangerous
ant prey with mucus. And we've already touched on like
(13:41):
the main aspect of this, but they provide one more
little detail that I really like. They're write quote. We
show that they're derived feeding kind of mattics are associated
with unique mucus secreting phar angel papilia that apparently serve
to immobilize and incapacitate dangerous ants as they are swallowed
by compacting them and binding them in mucus trans And
(14:04):
then 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 (14:14):
Take an ant as you 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,
(14:36):
all right, So 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
(14:58):
an excellent section in this book called the 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,
(15:19):
horned lizards are of course 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 armor moving on, they tend to have spikes and
(15:42):
scales along different parts of 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
(16:05):
just more modified scales, but the 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
(16:25):
can get, and so horned lizards 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
(16:47):
first one I want to look 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 2 (17:09):
Yeah yeah, they're quite quite fetching in their own right.
Speaker 3 (17:12):
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
(17:33):
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
(17:55):
would be a very no going back scenario. You know,
once you start eating a big one, you're committed.
Speaker 2 (18:00):
Yeah, yeah, you can't put it in reverse.
Speaker 3 (18:03):
Sherbrooke says in the book about defensive strategies that when
attacked by a leopard lizard a horned lizard, and again,
defensive strategies vary 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 as
(18:25):
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. Now,
the next category is birds. A number of different birds
prey on horned lizards. Sherbert mentions hawks such as the
(18:46):
red shouldered hawk or Boeo lineatus, 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,
(19:08):
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
(19:31):
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 their,
you know, their way of making a living, But I
cannot imagine eating something this spiky.
Speaker 2 (19:48):
And it's like a like a like a wheat then,
except even worse.
Speaker 3 (19:52):
Right, 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. Yep, 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
(20:12):
the horned lizard by 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
(20:34):
the lizard so it can be swallowed whole head first.
Rabbie 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 2 (20:51):
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 only seen. I've
only seen them in the wild, I think one or
two times while out 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 (21:10):
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 2 (21:22):
Clever girl.
Speaker 3 (21:23):
Yeah yeah, okay. So another bird predator, Chihuahuan ravens or
corvas crypto. Lucus 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,
(21:43):
but instead ripping them open and only feeding the soft
innerds to the hatchlings, so only guts for the children,
and then the carcass with the hard parts is discarded.
Speaker 2 (21:54):
All right, Well that's not surprising. I'll leave it to
the ravens to intelligently dissect before eating. To the end.
Speaker 3 (22:01):
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, swallowing them whole. Snakes,
(22:23):
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 hungry, but it can't get too greedy. It
has to know its limits. And so I guess there
(22:43):
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 gonna 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 gonna come back
to one more major category in a minute when we
get to the blood squirting. So there's another interesting framework
(23:06):
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 being caught, and third be
(23:28):
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 as when facing off against
(23:49):
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, and they've
got kind of short limbs and awkward movements. So mostly
horned lizards excel at number one and number three avoiding
(24:11):
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 lizards are masters of camouflage,
(24:33):
and Sherbrooke has an interesting side note about how we
often don't appreciate 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 is designed to help you
(24:56):
see the animals, such as like a picture in a
book or foot 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 likely might go right
(25:16):
by animals of this type and never see them, so
we wouldn't even know that we'd miss them.
Speaker 2 (25:21):
That's a great point.
Speaker 3 (25:22):
Yeah, And so 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
(25:43):
in their skin 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 color. This is found in many animals where varied
color patterns make it harder to pick out the outline
(26:07):
of an object 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 their groundcover.
But another thing they do often is if a predator
(26:29):
is nearby, they can flatten their bodies against the ground.
And this especially helps protect against, say, the visual detection
by birds, because this flattening 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,
(26:49):
it disrupts the predator's shape recognition. And the horned lizard's
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
(27:10):
one of these buddies, and it also helps that you
know as ectotherms, they need to spend a lot of
time 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
(27:32):
like video game playing styles I'm familiar with, is that
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
(27:54):
run very fast, very far, but the main purpose of
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,
(28:16):
I need to run to the opposite side of the
room and hide, and then they'll all be like where'd
he go?
Speaker 2 (28:21):
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.
Speaker 3 (28:28):
Huh.
Speaker 2 (28:29):
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,
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
(28:50):
in movement and then 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 (29:01):
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,
(29:26):
let's say all of that has failed. 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 defense strategies where you try
to make yourself look difficult to eat or dangerous to
the predator. Now, the range of behaviors described in Sherbrook's
(29:49):
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 respond 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 in
(30:11):
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,
(30:32):
if picked up and handled 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,
(30:53):
but I think it's generally understood that if you pretend
to be dead, you can wait for the predator to
relax its grip 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
(31:14):
maybe actually be harder to swallow. Remember, predators can die
from eating a horned lizard that is too big, so
you want the predator to be wondering if you are over.
Speaker 2 (31:24):
The line look more difficult to eat.
Speaker 3 (31:27):
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
(31:49):
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 want 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
(32:11):
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
(32:33):
majority at this point.
Speaker 2 (32:35):
I believe that's the case, but we can look again
at that data before we come back with part two
and clarify if we need to.
Speaker 3 (32:42):
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. Sherbrook 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
(33:03):
most of the time. You know, it's like one in
twenty times. It sounds nuts. So it was indeed sometimes
believed to be a myth, but it is real. So
Sherbroch 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
(33:27):
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,
(33:48):
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 2 (33:57):
That is crazy considering the size of these creatures.
Speaker 3 (34:00):
They're a little things, aren't they. Yeah. So does the
lizard lose a lot of blood from this? Yeah? 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 2 (34:16):
Better than losing all the blood and the body as well.
Speaker 3 (34:19):
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 muscles that they can use to squeeze closed the veins,
(34:43):
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 manifest tests externally as bulging eyelids. Eventually, the
(35:03):
pressure 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
(35:26):
what this means. Sherbroke writes, quote, humans sampling the blood
sprayed do not taste anything strongly objectionable.
Speaker 2 (35:36):
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
(35:59):
creature's blood.
Speaker 3 (36:00):
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
(36:22):
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 cannids such as the coyote and
the kit fox or Vulpius Macrotis any type of dog
attacks a horned lizard, Here come the blood jets. When
(36:45):
any of the sprayed blood gets into a dog's mouth.
Sherbrooke 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 2 (37:02):
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 it's just a different, a
different universe.
Speaker 3 (37:18):
Sherbroke 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 being severely bitten and tasted. And Sherberke
(37:42):
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,
(38:04):
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,
(38:25):
until you end up with six foot jets of eyeblood.
Speaker 2 (38:28):
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 (38:40):
But so why is this blood apparently distasteful to canids
to dogs?
Speaker 2 (38:45):
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 we understand that it's
(39:08):
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 (39:17):
That's right. Sherbrooke makes this point in the book that
it was once thought that maybe there were glands around
the eyes adding something to the blood before it gets
blasted out, but they said no, there's no evidence of that.
Speaker 2 (39:28):
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.
Speaker 3 (39:42):
Wow.
Speaker 2 (39:42):
Yeah, I didn't know that. Another interesting fact concerning horned
lizards here, they apparently don't eat fire ants. Fire Ants are,
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,
(40:06):
while also provoking human inhabitants to deploy anti ant measures
that you know, just don't discriminate. So all of this
plays a role in the habitat loss and decline of
various horned lizard species.
Speaker 3 (40:19):
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 2 (40:33):
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 this, 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 in like in quick bursts, because it's not
(40:55):
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 queen, you know, they're
not going to 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
populations necessarily. M But yes, it seems like the consumption
(41:19):
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 there there is one story we're going to come
(41:40):
back to about the Holy Toad who eats ants that
give him power. Whoa which is correct? The research they're
looking at here absolutely correct.
Speaker 3 (41:50):
I can't wait.
Speaker 2 (41:51):
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, write in. We'd love
to hear from you. We'll come back with part two
on Thursday. A reminder that that's when our core episodes
published Tuesdays and Thursdays every week and the Stuff to
(42:12):
Blow Your Mind 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 (42:26):
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 dot com.
Speaker 1 (42:47):
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 production of iHeartRadio.
Speaker 2 (00:12):
Hey, welcome to Stuff to Blow Your Mind. My name
is Robert.
Speaker 3 (00:15):
Lamb 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
(00:36):
more accurate lizard appellation because they are certainly not toads,
though there are reasons for calling them toads, mainly that
they look like toads.
Speaker 2 (00:46):
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. Throughout the episode.
Speaker 3 (01:02):
Horned Lizard makes me think learned lizard. You know, doesn't
it suggest a kind of wisdom?
Speaker 2 (01:08):
Yeah? Yeah, sometimes lizards can appear quite wise, so I buy.
Speaker 3 (01:13):
That, 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 2 (01:32):
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 Dne 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 (01:45):
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 have.
Speaker 2 (02:00):
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 (02:09):
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 2 (02:25):
That's right, Say yes to Xenomorph and then figure the
rest out later.
Speaker 3 (02:30):
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 2 (02:43):
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 (02:51):
M 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 in a and
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
(03:14):
potent 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
(03:36):
by the characters in the first movie, there's real danger
in injuring the creature. How do you fight it?
Speaker 2 (03:42):
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
(04:03):
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,
(04:25):
And of course this has also been used to various
effect 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 (04:43):
Is it really a spit because the animation looks to
me more like projectile vomit.
Speaker 2 (04:49):
I think it depends. At least in the first game.
He was in Mortal Kombat too, he would definitely spit.
I don't. It was like a kind of a sound
over and over again, and I think it got a
little more vomity later.
Speaker 3 (05:00):
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 2 (05:24):
That's right, because 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 the blood of its prey.
Speaker 3 (05:39):
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 2 (05:55):
That's right. They're kind of internet famous for this, a
lot of clips, a lot of animations and videos. I
should also add that if you know one thing, you
should probably know two things. Also, that they're to some
extent horned up right, because right, tall them horned lizards, right.
Speaker 3 (06:12):
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
(06:32):
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 horn Blizzard's weaponized blood is absolutely
real and it is the subject of some interesting scientific investigation.
Speaker 2 (06:49):
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
(07:11):
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 lizards in movies,
and there are a few that I was familiar with,
you know, because they're pretty popular films. I think what
Outlaw Josie Wales is on there.
Speaker 3 (07:33):
Yeah, yeah, but the wldye there 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 2 (07:48):
But also Jo Roowski'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
herbs 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 a it's
(08:11):
kind of 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.
Speaker 3 (08:20):
But it is not for everyone. Yeah, that's not movie
Night with the grandparents.
Speaker 2 (08:25):
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 like frogs and toads and lizards
(08:47):
standing in for the various actors and sides in this conflict.
Speaker 3 (08:51):
I did not remember that detail there's a lot I've
forgotten about Holy Mountain.
Speaker 2 (08:55):
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.
(09:17):
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.
(09:39):
And this is one of the species of bloodshooters.
Speaker 3 (09:42):
Yeah, that's right. But as you said, Rob, the various
species of horned lizards can be found all over the
western part of North America, from down to 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
(10:04):
regions 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
(10:25):
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
(10:46):
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 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
(11:08):
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 phrenos
(11:28):
as 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. You can
observe how they eat. Now. The different species of horned
lizards have some different different diets. Some are more taking
what they can get than others, but some are quite
(11:51):
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
(12:12):
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,
(12:34):
and this coating of mucus surrounds the ant as the
ant 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 lot
(12:56):
of meat on that bone. It's mostly bone.
Speaker 2 (12:58):
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,
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. But
(13:19):
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 incapacitate dangerous
ant prey with mucus. And we've already touched on like
(13:41):
the main aspect of this, but they provide one more
little detail that I really like. They're write quote. We
show that they're derived feeding kind of mattics are associated
with unique mucus secreting phar angel papilia that apparently serve
to immobilize and incapacitate dangerous ants as they are swallowed
by compacting them and binding them in mucus trans And
(14:04):
then 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 (14:14):
Take an ant as you 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,
(14:36):
all right, So 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
(14:58):
an excellent section in this book called the 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,
(15:19):
horned lizards are of course 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 armor moving on, they tend to have spikes and
(15:42):
scales along different parts of 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
(16:05):
just more modified scales, but the 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
(16:25):
can get, and so horned lizards 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
(16:47):
first one I want to look 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 2 (17:09):
Yeah yeah, they're quite quite fetching in their own right.
Speaker 3 (17:12):
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
(17:33):
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
(17:55):
would be a very no going back scenario. You know,
once you start eating a big one, you're committed.
Speaker 2 (18:00):
Yeah, yeah, you can't put it in reverse.
Speaker 3 (18:03):
Sherbrooke says in the book about defensive strategies that when
attacked by a leopard lizard a horned lizard, and again,
defensive strategies vary 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 as
(18:25):
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. Now,
the next category is birds. A number of different birds
prey on horned lizards. Sherbert mentions hawks such as the
(18:46):
red shouldered hawk or Boeo lineatus, 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,
(19:08):
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
(19:31):
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 their,
you know, their way of making a living, But I
cannot imagine eating something this spiky.
Speaker 2 (19:48):
And it's like a like a like a wheat then,
except even worse.
Speaker 3 (19:52):
Right, 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. Yep, 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
(20:12):
the horned lizard by 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
(20:34):
the lizard so it can be swallowed whole head first.
Rabbie 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 2 (20:51):
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 only seen. I've
only seen them in the wild, I think one or
two times while out 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 (21:10):
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 2 (21:22):
Clever girl.
Speaker 3 (21:23):
Yeah yeah, okay. So another bird predator, Chihuahuan ravens or
corvas crypto. Lucus 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,
(21:43):
but instead ripping them open and only feeding the soft
innerds to the hatchlings, so only guts for the children,
and then the carcass with the hard parts is discarded.
Speaker 2 (21:54):
All right, Well that's not surprising. I'll leave it to
the ravens to intelligently dissect before eating. To the end.
Speaker 3 (22:01):
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, swallowing them whole. Snakes,
(22:23):
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 hungry, but it can't get too greedy. It
has to know its limits. And so I guess there
(22:43):
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 gonna 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 gonna come back
to one more major category in a minute when we
get to the blood squirting. So there's another interesting framework
(23:06):
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 being caught, and third be
(23:28):
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 as when facing off against
(23:49):
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, and they've
got kind of short limbs and awkward movements. So mostly
horned lizards excel at number one and number three avoiding
(24:11):
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 lizards are masters of camouflage,
(24:33):
and Sherbrooke has an interesting side note about how we
often don't appreciate 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 is designed to help you
(24:56):
see the animals, such as like a picture in a
book or foot 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 likely might go right
(25:16):
by animals of this type and never see them, so
we wouldn't even know that we'd miss them.
Speaker 2 (25:21):
That's a great point.
Speaker 3 (25:22):
Yeah, And so 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
(25:43):
in their skin 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 color. This is found in many animals where varied
color patterns make it harder to pick out the outline
(26:07):
of an object 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 their groundcover.
But another thing they do often is if a predator
(26:29):
is nearby, they can flatten their bodies against the ground.
And this especially helps protect against, say, the visual detection
by birds, because this flattening 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,
(26:49):
it disrupts the predator's shape recognition. And the horned lizard's
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
(27:10):
one of these buddies, and it also helps that you
know as ectotherms, they need to spend a lot of
time 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
(27:32):
like video game playing styles I'm familiar with, is that
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
(27:54):
run very fast, very far, but the main purpose of
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,
(28:16):
I need to run to the opposite side of the
room and hide, and then they'll all be like where'd
he go?
Speaker 2 (28:21):
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.
Speaker 3 (28:28):
Huh.
Speaker 2 (28:29):
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,
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
(28:50):
in movement and then 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 (29:01):
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,
(29:26):
let's say all of that has failed. 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 defense strategies where you try
to make yourself look difficult to eat or dangerous to
the predator. Now, the range of behaviors described in Sherbrook's
(29:49):
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 respond 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 in
(30:11):
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,
(30:32):
if picked up and handled 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,
(30:53):
but I think it's generally understood that if you pretend
to be dead, you can wait for the predator to
relax its grip 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
(31:14):
maybe actually be harder to swallow. Remember, predators can die
from eating a horned lizard that is too big, so
you want the predator to be wondering if you are over.
Speaker 2 (31:24):
The line look more difficult to eat.
Speaker 3 (31:27):
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
(31:49):
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 want 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
(32:11):
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
(32:33):
majority at this point.
Speaker 2 (32:35):
I believe that's the case, but we can look again
at that data before we come back with part two
and clarify if we need to.
Speaker 3 (32:42):
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. Sherbrook 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
(33:03):
most of the time. You know, it's like one in
twenty times. It sounds nuts. So it was indeed sometimes
believed to be a myth, but it is real. So
Sherbroch 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
(33:27):
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,
(33:48):
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 2 (33:57):
That is crazy considering the size of these creatures.
Speaker 3 (34:00):
They're a little things, aren't they. Yeah. So does the
lizard lose a lot of blood from this? Yeah? 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 2 (34:16):
Better than losing all the blood and the body as well.
Speaker 3 (34:19):
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 muscles that they can use to squeeze closed the veins,
(34:43):
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 manifest tests externally as bulging eyelids. Eventually, the
(35:03):
pressure 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
(35:26):
what this means. Sherbroke writes, quote, humans sampling the blood
sprayed do not taste anything strongly objectionable.
Speaker 2 (35:36):
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
(35:59):
creature's blood.
Speaker 3 (36:00):
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
(36:22):
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 cannids such as the coyote and
the kit fox or Vulpius Macrotis any type of dog
attacks a horned lizard, Here come the blood jets. When
(36:45):
any of the sprayed blood gets into a dog's mouth.
Sherbrooke 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 2 (37:02):
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 it's just a different, a
different universe.
Speaker 3 (37:18):
Sherbroke 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 being severely bitten and tasted. And Sherberke
(37:42):
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,
(38:04):
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,
(38:25):
until you end up with six foot jets of eyeblood.
Speaker 2 (38:28):
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 (38:40):
But so why is this blood apparently distasteful to canids
to dogs?
Speaker 2 (38:45):
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 we understand that it's
(39:08):
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 (39:17):
That's right. Sherbrooke makes this point in the book that
it was once thought that maybe there were glands around
the eyes adding something to the blood before it gets
blasted out, but they said no, there's no evidence of that.
Speaker 2 (39:28):
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.
Speaker 3 (39:42):
Wow.
Speaker 2 (39:42):
Yeah, I didn't know that. Another interesting fact concerning horned
lizards here, they apparently don't eat fire ants. Fire Ants are,
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,
(40:06):
while also provoking human inhabitants to deploy anti ant measures
that you know, just don't discriminate. So all of this
plays a role in the habitat loss and decline of
various horned lizard species.
Speaker 3 (40:19):
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 2 (40:33):
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 this, 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 in like in quick bursts, because it's not
(40:55):
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 queen, you know, they're
not going to 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
populations necessarily. M But yes, it seems like the consumption
(41:19):
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 there there is one story we're going to come
(41:40):
back to about the Holy Toad who eats ants that
give him power. Whoa which is correct? The research they're
looking at here absolutely correct.
Speaker 3 (41:50):
I can't wait.
Speaker 2 (41:51):
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, write in. We'd love
to hear from you. We'll come back with part two
on Thursday. A reminder that that's when our core episodes
published Tuesdays and Thursdays every week and the Stuff to
(42:12):
Blow Your Mind 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 (42:26):
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 dot com.
Speaker 1 (42:47):
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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Does hearing about a true crime case always leave you scouring the internet for the truth behind the story? Dive into your next mystery with Crime Junkie. Every Monday, join your host Ashley Flowers as she unravels all the details of infamous and underreported true crime cases with her best friend Brit Prawat. From cold cases to missing persons and heroes in our community who seek justice, Crime Junkie is your destination for theories and stories you won’t hear anywhere else. Whether you're a seasoned true crime enthusiast or new to the genre, you'll find yourself on the edge of your seat awaiting a new episode every Monday. If you can never get enough true crime... Congratulations, you’ve found your people. Follow to join a community of Crime Junkies! Crime Junkie is presented by audiochuck Media Company.