Jane: This is But Why: A Podcast for Curious Kids from Vermont
Public. I'm Jane Lindholm. Today, we have a bonus episode
for you all about some very special lizards. We're picking
up right where we left off last week, down in the basement of
the San Diego Natural History Museum. I went there to talk
with Adam Clause, who manages the herpetology collection at
the museum herpetology is the study of reptiles and
amphibians, which is actually kind of an odd pairing, as it
turns out, because reptiles and amphibians aren't actually all
that closely related.
Adam: It's really just a historical thing that has been
carried through to the present day. So it dates back to the
founder of taxonomy, Carolus Linnaeus. I don't know if
anybody's heard of him, but he's the one who sort of created the
system of scientific names for animals, which can always
consist of two parts, right? And so he considered anything that
didn't have sort of blood that sort of control its own
temperature. So the way we control our own blood
temperature, reptiles and amphibians do not, and so he
considered anything that sort of didn't have these
characteristics as very primitive, sort of creepy, kind
of disgusting organisms. And so just by virtue of that very
arbitrary classification, reptiles and amphibians were
lumped together, even though they're not necessarily each
other's closest relatives. So birds are actually more closely
related to reptiles, because they actually are a type of
reptile, but we don't study birds in herpetology that sort
of got pulled out, and it's the ornithologists who study that.
So it's this weird mix. These are not necessarily animals that
are all that similar, they're not all that closely related,
but we continue to study them in this way today, and for me, it's
really exciting, because I get to study a very diverse group of
animals. It's hard to imagine very, a more different group of
animals than frogs and snakes, right? But these are all lumped
together, and so it's a very exciting group of animals to
work with and to study.
Jane: We went to see Adam because you all have sent us a
lot of questions about lizards, and you've sent us so many
lizard questions, in fact, that we couldn't even fit them all in
one episode. So we started last week, and we're back today, and
in this bonus episode, we're going to narrow our focus even
more from reptiles to lizards to specific types of lizards. And a
lot of you have questions about one of the most famous lizards,
the chameleon. And when I say a lot of you. I mean a lot of you.
Jonathan: Hi, my name is Jonathan. I'm six years old, and
I'm from Australia. My question is, how do chameleons change
color? Bye!
Noah: Hi. My name is Noah. I live in New Hampshire, and I'm 4
years old.
Hank: My name is Hank. I live in Lubbock, Texas. I am about to be
six.
Lorelai: My name is Lorelai, and I'm five years old, and I live
in New York, and I want to know what colors do chameleons
change?
Joseph: My name's Jasper. I'm eight years old and I'm from
Pennsylvania.
Luke: Hi, my name is Luke. I'm eight years old, and I live in
Hong Kong.
Clara: My name is Clara. I'm seven years old. I live in St
Paul, Minnesota.
Mikko: I'm Mikko. I am six years old. I live in Seguin, Texas.
Blair: Hi, my name is Blair, and I live in New Jersey, and I'm
six years old.
Henry: My name is Henry, and I am eight years old. I live in
Georgetown, Texas.
Lucy: My name is Lucy, and I live in Connecticut, and I'm six
years old.
Holly: Hi, my name is Holly. I'm from Calgary, Alberta. I'm seven
years old.
Abraham: My name is Abraham, and I'm from Newton, Massachusetts.
Adult: How old are you?
Abraham: And I'm six years old.
Sadie: Hi, my name is Sadie, and I'm eight years old, and I'm
from Munster, Indiana.
Kevin: My name is Kevin. I am eight years old.
Otis: My name is Otis. I'm six years old. I live in Baltimore.
Caroline: My name is Caroline, and I live in Houston, Texas,
and I'm six years old.
Berkeley: Hi, my name is Berkeley. I live in San Antonio,
Texas. I'm eight years old, almost nine.
Harlan: Hello. My name is Harlan. I work in Aspen in
Colorado. I'm five. My question is, what happens inside
chameleon's body when they turn color?
Webb: My name is Webb, and I live in Abilene, Texas, and I am
six years old.
Dashel: My name is Daschle, and I am from Durham, North
Carolina, and I am six years old.
Atticus: I live in Rochester Hills, Michigan, and my age is
three and a half. My name is Atticus.
Leo: My name is Leo, and I'm four years old, and I'm from
Maine.
Brandon: Hi. My name is Brandon, and I am seven years old, and I
live from Bradford, Vermont.
Vivian: Hi, my name is Vivian. I am six years old. I live in
Michigan.
Asher: Hello, my name is Asher. I am five years old. I am from
Millbank, California.
JD: Hello. My name is JD. I'm from Chicago. I am nine years
old.
Riley: My name is Riley. I'm five years old. I live in
Longmont, Colorado.
Jane: My name is Jane. My age is six. I live in Woodinville,
Washington.
Miles: Hello. My name is Miles. I'm six years old, and I'm
calling from South Africa and Pretoria.
Will: My name is Will, and I'm four years old, and I live in
Virginia. How do chameleons change color?
Adam: I want to start by saying that it's important to remember
that there's not just one type of chameleon out there. There's
actually hundreds of different types of chameleons, and they
can range from really big, like the size of your Bearded Dragon,
to smaller than your pinky finger. So there's a lot of
diversity within chameleons, but one of the things that they
share is that they can all to some degree or another, they can
change the patterning on the surface of their skin, and the
way they do that is on their in the individual scales of their
skin, there are these little packets of pigment, and these
packets of pigment can sort of be expanded or contracted
through muscular action and nerve endings. And so the
lizards can expand or contract all over their skin, sort of all
at the same time, all these little, tiny pinpricks worth of
color that are in their scales. And by changing whether they're
expanded or contracted, they can show certain colors or conceal
other colors. And through that mechanism, they can sort of
become whatever they want to, in a way.
Jane: If you want to know more about how chameleons change
their color, we have a video episode all about it, if you ask
your adults to help you get to but why kids on YouTube, you can
watch me change color. Coming up, Komodo dragons, green
iguanas and Tuataras. Oh my!
This is But Why. And today, we're learning all about lizards
with herpetologist Adam Clause, who manages a collection of
80,000 reptile and amphibian specimens at the San Diego
Natural History Museum. He's helping us learn about some very
specific kinds of lizards today. We've gotten a lot of questions
about Komodo dragons, and I share your interest in them.
Kids are curious about is a Komodo dragon?
Adam: Yeah. So Komodo dragons are the largest lizard that
currently lives on planet Earth. So they can be well over 20 feet
long. They're only found on a few small islands in Indonesia,
which is in Southeast Asia. They're really remarkable
animals in many ways, not just because of their size. They're
also really interesting because they have bacteria in their
mouth as well as actual venom in their salivary components.
Jane: So you don't want to get bitten by one.
Adam: For both reasons. No, they have very dirty mouths, and they
have venomous mouths as well. And so they're using that
combination of bacteria and venom to help subdue their prey.
And so they'll often eat really large things like water buffalo.
And so they will sort of bite a water buffalo, break some blood
vessels and introduce both the bacteria and the venom into the
animal's bloodstream. It's getting a little bit gruesome,
maybe too gruesome, but...
Jane: Nothing's too gruesome for us.
Adam: And so the animal, basically, they're anticoagulant
compounds, so the animal, the blood doesn't coagulate, and so
the blood just continues to flow from that wound until the animal
then loses consciousness. And then the Komodo dragon is using
its very long forked tongue to track where that prey animal
went and where it died. And then they follow it to that point,
and then they finish eating it at that point.
Max: Hi, I'm Max, and I live in Utah, and I'm eight years old.
And my question is, why are Komodo dragons called Komodo
dragons, if they're not a dragon?
Summer: Hello. My name is Summer, and I live in Portland,
Oregon, and I'm four and a half years old, and why are Komodo
dragons called Komodo dragons? Are they really dragon?
Jane: The Komodo part comes from the Indonesian island of Komodo,
where Europeans and Americans first saw these lizards. People
who lived on the islands where these giant reptiles roam called
them ora, meaning land crocodiles. The visiting
scientists thought these creatures had a fearsome
reputation. Nation, and they're really, really big, so they
called them dragons.
Quincy: My name is Quincy. I'm eight years old, and I live in
Austin, Texas. How do Komodo dragons survive when they're
endangered?
Jane: There are a lot of factors why Komodo dragon populations
are declining, including things like habitat loss and poaching
and natural factors like earthquakes, volcanoes and fire.
Climate change is another big factor that threatens their
survival. A lot of people are working to protect Komodo
dragons, and the largest population of these lizards are
in the Komodo National Park where they have protected
status.
Ashley: My name is Ashley, and I live from Rockville, Maryland,
and I'm four years old. How do Komodo dragons fight on two legs
without falling off their two hind legs?
Adam: They just have really good balance, so it gets back to that
tail, so they'll use their tail as a counter balance, and so
they'll have by having their tail out extended, extended
really well, that helps keep them from from flopping over.
Silas: My name is Silas, and I'm from Louisville, Kentucky. I'm
seven years old, and my question is, how do Komodo Dragons get
bacteria in their mouth?
Adam: It's just part of the bacteria that's just sort of
around in their environment. And so similar to the way all of us
have bacteria in our guts, right? They pick that up from
the environment, part of it maybe comes from their moms.
We're not quite sure.
Alexandra: Hi, my name is Alexandra. I live in Fort
Collins, Colorado. My question is, how many babies do monitor
lizards have at a time?
Jane: Alexandra is wondering, how many babies do monitor
lizards have at a time?
Adam: Totally depends. Again, similar to chameleons, there's
no one type of monitor lizard. There's dozens of different
monitor species that range from the largest lizard on the
planet, the Komodo dragon, to dwarf monitors, which are
smaller than your bearded dragon. And so it depends on the
species, anywhere from probably a couple eggs to maybe a dozen,
something like that.
Jane: Alright. And one more related question.
Will: My name is Will, and I live in Atlanta, Georgia, my
question is, if the Komodo Dragon is the biggest lizard,
what is the smallest lizard?
Adam: There's a number of different competitors for the
title of smallest lizard in the world. So we talked a little bit
earlier about these little, dwarf, mini chameleons that are,
like, smaller than your pinky finger. So some of those are a
good candidate. And then there's also these really tiny geckos
called dwarf geckos, that many of which occur only on islands
in the Caribbean. And those are also extremely tiny, where you
could have a full size adult coil up comfortably on a dime, a
US dime.
Jane: So they're like, maybe your biggest fingernail size.
Adam: Yeah, they're really, really tiny. And what's
interesting is that most of these really tiny lizards, they
live in leaf litter. That's their habitat. So the same for
these tiny chameleons, they're in the leaf litter, as well as
these little, tiny geckos on Caribbean islands, they're
they're hanging around in the leaves, fallen leaves on the
ground.
Jane: That would be so cute to see. How about iguanas?
Hudson: I'm Hudson, and I am five years old, and I live in
Arvada, Colorado, and what my question is is, why are iguanas
or lizards green most of their time?
Adam: Mostly it's a camouflage thing. So iguanas, green
iguanas, specifically, they're arboreal, which means they spend
most of their lives up in trees, and so their green color helps
them to camouflage among the leafy branches where they live.
Jane: Interestingly, Hudson green iguanas aren't always
green. When I was in Florida doing some But Why reporting
about invasive species a few years ago, I saw a lot of big
green iguanas that were actually orange. Mature males often turn
orange during the breeding season from about December
through April.
Roshan: Hi, my name is Roshan and I'm five years old, and I
want to know, why do iguana have spiky things on their back?
Adam: That's a great question. So male green iguanas, in
particular, they're using those spikes as a way to show off to
females how healthy and vigorous they are. And then it's a little
bit of a defensive thing, where those those scales can sort of
protect against predators, but it's mostly for sort of showing
off to the females.
Wyatt: My name is Wyatt, and I am five years old. I live in Los
Angeles, California. My question is, why do male iguanas have
dewlaps?
Jane: Wyatt has obviously learned a little bit about
iguanas for people who don't. Know what a dewlap is. Can you
tell us that too?
Adam: Yeah. So a dewlap is this sort of thin, flexible flap of
skin that hangs down from the throat of iguanas. They can't
really control it. It just sort of lays there. There are other
lizards called anoles, which some of you may have heard of,
and they can actually push their dewlap out or retract it flat
against their throat. In the case of the anoles, the dewlap
is often very brightly colored, and so it's mostly male anoles
that have these colored dewlaps, or flaps of skin under their
throat, and they're using them to signal to other males for
territorial interactions and also to signal to females, hey,
I'm over here. I'm very vigorous. I might be a good
mate. For iguanas, they're more it's just a thing that males
have again, to sort of signal their vigor. So bigger adult
male iguanas have bigger dewlaps, and they might make
better mates in minds of the female iguanas.
Joseph: Hi. My name is Joseph. I'm six years old. I live in
Maryland. I'm wondering how some gliding reptiles like the Draco
lizard, glide halfway through the air and catch themselves on
trees.
Adam: This is one of my favorite groups of lizards. So if you're
listening right now, what you can do is you can if you hug
yourself, not sort of on your shoulders, but sort of around
your stomach, where your hands are positioned, they're
positioned over your rib cage. You can sort of feel your ribs
if you press into your body. So the Draco lizards, the wings
that they have are basically their modified ribs. Their
modified rib cage. So now, if you take your arms and you keep
your elbows pressed tightly against your sides and you flare
your arms out, you can imagine that your arms are sort of your
ribs, and that's what Draco lizards do. They can take their
ribs from being sort of flat against their bodies, and they
can flare them out to create these wings, effectively wings,
and they use those wings to then glide from tree to tree in the
forest where they live.
Jane: How do they catch themselves on the tree without
smashing into it?
Adam: So they'll sort of break, they'll sort of flare their
wings up and catch the air and slow down right before impact.
But because they're so light, these are not large lizards. You
know, they're about the size of Fence lizards. For those of you
who might grow up, might have grown up with those, they're
much smaller than a bearded dragon. They're sort of like
half the size of a leopard gecko, typically, and they're
very, sort of slender, so they're not super heavy, so they
don't have a big impact when they hit a tree after flying
from another tree, and so they're not creating a lot of
force. And so they can just sort of plop onto the side of the
tree and grab on with their claws, and they're good to go.
Jane: All right, one other type of lizard that we have a
question or type of animal that we have a question about:
Nikki: Hi, my name is Nikki, and I'm nine years old. I'm from
Israel. Why is tuatara not a lizard?
Adam: This is another really good question. And so without
getting too much into the details, it's because they have
a bunch of different structures in their skeleton that no
lizards have. And so tuataras branched off on the tree of life
before, earlier than any other lizard. And so they're what we
call sister to all other lizards. So a good way to think
about is that all true lizards are more closely related to each
other than any of them is to the tuatara. The tuatara is sort of
this weird offshoot in the tree of life, the reptile tree of
life. And even though they look externally a lot like a lizard,
there's a number of different features of their ribs, of their
skull, of their teeth that no lizards have. And so they're
very special in that way.
Jane: What do they look like?
Adam: They look kind of like iguana, like a brown iguana.
They don't grow quite as big as green iguanas, and their tail
isn't as long, but they're sort of spiky. They have a crest
along their back. To all intents and purposes, they sort of just
look like a big lizard, but they are not lizards.
Jane: Is there anything else that you think kids should know
about lizards? A lot of us are very interested in them. But you
know what's something that you could send us off with as
something else to think about or investigate on our own about
lizards?
Adam: Yeah, so one of the things that I'm really interested in,
and is really important to me, is making sure that we're trying
to do our best to keep lizards around. A lot of lizards are in
trouble all across the world, and Southern California is no
different, and one of the biggest things that anybody can
do to help protect lizards is to not use pesticides in your
gardens. So pesticides typically kill insects, and most lizards
feed on insects, and so if you're killing off all the
insects, the lizards have nothing to eat and they
disappear. So by not using pesticides, you will help out
your local lizards, and I think we all stand to benefit from
that.
Jane: That's a great place to end it. Thanks so much to Adam
Clause, collections manager of herpetology at the San Diego
Natural History Museum. We loved going to see the reptile and
amphibian specimens in the museum's collection. As you
know, you can ask us a question on just about anything. Have
your adult help you, record you asking the question. They can
use a free voice app that comes on a smartphone, then send it to
questions@butwhykids.org but why is made at Vermont public and
distributed by PRX. Our producers are Sarah Baik, Melody
Bodette and me, Jane Lindholm, Joey Palumbo is our video
producer, and Luke Reynolds wrote and performed our theme
music. If you like our show, please give us a review or a
like on whatever platform you use to listen to us, we'll be
back in one week with an all new episode. Until then, stay
curious!