ANNA KUSLER: Hi, my name's Anna.
JESSICA TINGLE: And I'm Jess.
ANNA KUSLER: And we're here to talk to you about the awesome field of herpetology.
JESSICA TINGLE: Herpetology is the study of reptiles and amphibians. But, today, we're going to focus on reptiles. First, let's talk about what makes a reptile a reptile. They're one of the first groups of animals that were truly adapted to living on land, and they have lots of special characteristics to help them with that.
One of them is the way they breathe. Unlike fish and many amphibians, reptiles breathe air. They don't have gills.
They have another special adaptation that helps them live on land, which has to do with their eggs. If you ever see amphibian eggs, they're big, jelly-like masses. And you always find them in water because they don't have hard shells like a reptile egg do. Some reptile eggs have hard shells, and some have leathery shells. But all of them are able to survive on land.
Another really cool feature of reptiles has to do with their skin. Mammals have fur. Birds have feathers. But reptiles have scales.
Something really cool about them is that they shed their scales. Some, like snakes, shed it all in one long piece. And you can see that here. Others are different.
Alligators and crocodiles, for example, will shed one scale at a time every once in a while throughout their lives. And lizards will often shed it in strips. And some of them even eat their skin as they shed it.
Finally, a characteristic of reptiles is that they're ectothermic. Lots of people call this cold-blooded, but I don't really like this term for a lot of reasons. It kind of makes you think that their blood is cold, which isn't actually the case.
All it means is that they can't generate their own body heat. The word ectothermic comes from Greek, ektos meaning outside, and thermic as in heat like a thermometer. So they have to get their heat from outside sources, like the sun. Or some of our pet reptiles really like to sit on us because, as mammals, we have really warm skin that can heat them up.
ANNA KUSLER: So we've got four main kinds of reptiles-- lizards, like my friend, Spike, here who's a bearded dragon, snakes, turtles and tortoises, and crocodilians, which includes gharials, caimans, crocodiles, and alligators. So a lizard's ability to eat is as varied as they are. Some kinds of lizards are entirely carnivorous. So like the crocodiles, they grab prey with their mouth.
Others, like Spike here, have basically just a blobby, sticky tongue, and they eat things that are in close range right around their head. So they basically just open their mouth, tongue will flick out a little bit, pick up whatever is on the ground, and bring it back in. So some, like the chameleon, which you may be familiar with, are able to project their tongue really long distances, sometimes over 12 inches. They have a specialized muscle in the back of their throat that allows their tongue to be thrown out of their mouth and then sucked back in.
So lizards are a really interesting and diverse group of reptiles. They're found on every continent, except Antarctica, and they're adapted for living in about just about any environment. You can find them in the trees, on the ground, and even in the water sometimes.
They're really diverse, but there are a couple of characteristics that you can find in every species. It's kind of hard to see on her, but they all have an external ear. It's that little hole right next to her eye. They also tend to have eyelids. But, as you can see with this species, they do not.
So snakes are pretty distinct. In terms of identifying them from other reptiles, the easiest characteristic is the lack of arms and legs. But there's also some characteristics about their head that set them apart. They obviously have no external ear, and they also don't have any eyelids.
So turtles and tortoises are a really interesting and unique group of reptiles. They're found on every continent, except Antarctica, and they're adapted to life in the water and on land. But there's one thing that unites them all, and that is their characteristic shell. All shells are composed of three parts. You've got the carapace, which is the top part, the plastron, which is the bottom, and the bridge, which connects the two.
Now turtles and tortoises eat a whole bunch of different stuff. There are ones that are entirely carnivorous that live in the water and on land. You've got ones like Rocky here that eat nothing except plants. And then you have lots of different kinds that eat a combination of plants and animals, and that's called omnivory.
So unlike any other reptile, turtles and tortoises actually lack teeth. Instead of having teeth, they have a specialized hard, bony beak, as you can see on my friend, Rocky, here. Now turtles and tortoises eat a really varied diet. Some of them eat plants and vegetables, like my friend, Rocky, here.
Their beak acts like a pair of kitchen shears and will cut through the vegetation very easily. Other turtles are entirely carnivorous, meaning they animals. So the alligator snapping turtle waits under the water with his mouth open.
He has a specialized tongue that looks like a little lure. It's like a worm. He'll wiggle his tongue underneath the water, and fish will be attracted to it. They'll swim into his mouth, looking for a meal, and then they themselves end up being the meal.
JESSICA TINGLE: As you can see, they've got really sharp teeth, which are great for catching and eating prey. They're usually ambush predators, so they wait in the shallow water. And then when another animal comes down to drink, they grab it by the leg and pull it in, at which point they start to roll over and drown the animal. Once it's drown, they can eat it.
ANNA KUSLER: Crocodilians are only found in the tropics. They need it to be warm. They can get huge. Some species can even reach up to 20 feet long.
Another really cool characteristic is that they have really interesting parental care. Mothers will build giant nests, which they will protect and guard from scavengers. When the babies are born, they'll help dig up the nests and move the babies to the water and guard them for several weeks.
JESSICA TINGLE: So on people and on reptiles and on a lot of other vertebrates, you have the top jaw, where our top teeth are, and the bottom jaw, where our bottom teeth are. Now, for us, you can feel near to your ear, if you open and close your mouth, the joint where your bottom and top jaw connect with each other. In snakes, they can actually disconnect those two. So their bottom jaw can drop down really wide to swallow really tall prey.
They have another special jaw adaptation, and that's with their bottom jaw. If you feel your chin and wiggle your finger around a little bit, you can kind of feel a dimple. And that's a spot where two different bones of your bottom jaw come together. So let's say my hands are the bottom jaw, and these are the two separate bones.
So instead of being fused together, like in people, they're actually not. They're open like this. And they can move them independently so that when they swallow prey, one can move forward and grasp on. And then the other half of the bottom jaw can move forward. And so they walk their jaw, pulling their head and body over the prey.
Like I said before, if you want to survive in the wild, there are two really important things you have to do. I already talked about eating. But what about not getting eaten? That's where defense comes in.
And one really big way to defend yourself is by your coloration. Now the sort of coloration defense you're probably most familiar with is camouflage. An animal can be hidden in plain sight. A predator will never see you if you look just like the bark of the tree you're sitting on or just like a leaf or just like whatever other habitat that you happen to be in.
A second type of coloration defense is warning coloration. Poisonous or venomous animals don't want to blend in. They want to advertise their poison. So they'll wear bright colors, like red or orange, or even a bunch of different bright colors.
And that tells predators to stay away. A predator sees them, and they know to not get near because if they eat that animal, they'll end up with a stomachache or even dead. Now some trickster animals like to take advantage of that. They do something called mimicry, where they wear bright colors even though they don't have venom or poison. They look just like the venomous animals, so predators stay away because it's not worth the risk.
ANNA KUSLER: So aside from defensive coloration, like camouflage and warning colors, there's lots of really cool physical adaptations that reptiles can have to keeping safe. The most obvious is the turtle shell. As you can see, in a turtle shell, it has two parts. There's the bony underpart that's made of actual bone. And then there's the top part, which is made of keratin, the same thing that makes up our fingernails.
Now unlike a crab, for example, like a hermit crab, that has to shed its shell every time it gets bigger, a turtle shell grows with the turtle itself. As you can see in here, the vertebrae actually line the inside of the shell. There's a lot of variation in size with turtles. Some may only get to be a few inches long, whereas others, like Rocky, can almost get to be as big as a coffee table.
So not all reptiles have the luxury of a turtle shell for keeping themselves safe. Others, like Spike, have really specialized scales that they use to defend themselves. Now, as you can see here, I'm touching Spike's scales, and they're actually quite soft to the touch. I don't appear to be in any pain.
However, if a predator was to come along and scare her, she does what I call the pufferfish blow. Now I'm sure a lot of you are familiar with the concept of a pufferfish blowing themselves up, right? Well, Spike can do just about the same thing. If a predator comes along and tries to nab her, she can puff herself up full of air, make herself look bigger than life, and all of these spikes will stand out erect. And they'll become very sharp and really difficult.
Now I can imagine you probably wouldn't want to eat a cheeseburger that's covered in spines. It might go down a little bit unpleasant-- the same idea with these guys. Once she's all blown up with air, nothing's going to want to swallow her.
So I hope some of the cool things that we've shown you about reptiles and their amazing diversity has gotten you excited about them. So, hopefully, you might want to go out and find some. Here are some tips for how to do that.
First of all, they like to be out when it's warm. So a good place to start is looking on nice stone rocks or on, in the case of turtles, branches that are extending out of the water. You can flip the rocks over and look underneath, but, please remember, please handle the animals with respect and always be very gentle.
JESSICA TINGLE: Once you find a reptile, you'll probably want to know what it is. A good way to do that is to get a field guide, like this one. My field guide is Reptiles and Amphibians of Eastern and Central North America because that's where I live. So get one for your region.
They're great because you can open them up and find a picture. And once you see a picture that looks like the reptile you found, you can then go to another part of the book that will tell you all about it. There are a lot of other really good resources if you want to keep learning about reptiles. Check out your library for books or find documentaries. But get out there and explore most of all.
ANNA KUSLER: We hope that you've gotten as excited about reptiles as we are.
JESSICA TINGLE: So now get out there and find some.
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Like lizards? Anna and Jessica do! Join these Cornell students as they differentiate reptiles from amphibians, discuss the study of herpetology, and break reptiles down into the classifications of Crocodilians, Turtles, Snakes, and Lizards.