This is But Why, a podcast for curious kids from Vermont Public.
I'm Jane Lenton. In this show, we take questions from curious kids just like you and we find answers.
You send us a lot of questions about animals and that is A.O.K.
with me because if you haven't already guessed, I love animals too.
When I was a kid, I wanted to be a marine biologist, a journalist and a zookeeper.
Well, I guess one out of three ain't bad, right?
Anyway, I have always loved learning about animals and so do Melody and Kiana and so we are more than happy to tackle all of your animal questions.
The animals we're going to talk about today are not the cute and cuddly kind, but they are still fascinating and even beloved in their own way.
We're learning about crocodilians and we're going to learn about them from a researcher who knows a lot about reptiles.
I'm Dr. Venisha Briggs Gonzalez and I am at the University of Florida with the Crocodocs Lab at Fort Lauderdale Research and Education Center.
As she mentioned, Venisha Briggs Gonzalez, who likes to go by Dr.
V, is part of a group of researchers known as the Crocodocs.
So the Crocodocs, it's a really cool story actually, it goes back to like very early 1970s, my boss, Dr.
Frank Mazzotti, he was out with a journalist and there was a Hatchling crocodile that wasn't doing so well and he gave it mouth to mouth CPR and the journalist at the time dubbed him the original Crocodocter and it stuck many, many years later.
Most of you aren't giving mouth to mouth to crocodiles though, you're not treating them like a vet would, usually.
Not usually, although I can't say that we have not kissed them, you know, some folks are always looking for that pridence on the other side, it might be in the form of a crocodile.
Kids I don't recommend kissing any crocodiles, whatever Dr.
V says that's fine but please don't go kissing crocodiles.
So when we talk about Crocs, we're not actually just talking about crocodiles, you're talking about crocodilians, who are the crocodilians?
So the crocodilians are a really big group of animals but they all essentially look the same and are super closely related.
So crocodiles, alligators, came in, were just very similar and garrioles, so garrioles have that really long snout, they are all crocodilians.
Typically, when we say Crocs though, I think we are actually referring to crocodiles.
What do you have here in Southern Florida?
Oh, we've got it all. In Southern Florida, we have our native species, which are the American crocodile and the American alligator.
We have a few species of invasive came in here that we have been removing because they do cause harm to the native wildlife.
We do not have garrioles, garrioles are only found in India.
Here are came in usually found, where is their native habitat.
So native came in are found in South America.
Everything is brought to South Florida as pets and released when they get really big.
We've actually done a whole episode about invasive species and specifically some of the reptiles like came in that have made South Florida their home.
Invasive plants and animals can cause a lot of problems for the wildlife that is indigenous to the area.
And if you want to learn about some of the ways to prevent the spread of invasive species, go back and listen to that episode.
Now you've sent us quite a few questions about crocodilians, so we asked Dr.
V if she'd take a crack at answering them.
Hi, my name is Quentin and I am six and a half years old and I live in Alaska and Orange and my question is why do lizards have scales?
My name is Argus, I live in Tokyo, Australia and I'm six and a half to seven.
And my question is why do lizards have scales?
Hi, my name is Rowan, I am six years old, I live in Houston, Texas and my question is why do lizards have scales?
All lizards do have scales and they have them to serve a variety of purposes because lizards are considered cold blooded that means they do not generate their own body heat, they have to absorb the heat from the surface that they're on or from the sunshine or from whatever is around in their environment.
So the scales help to keep the warmth in and also helps to keep them cool on days when it's not very, very warm.
Scales also help to protect them, it's a defense mechanism, scales are tough to break through, bite through, cut through and of course it also serves as camouflage.
So scales have colors, it has pigments that are either structural or non-structural and that can help them blend in or stand out and prove that either they're dangerous or noxious or not.
You mentioned that scales are helpful because lizards are cold blooded so they have to regulate their temperature by the outside factors around them and there are a lot of kids who want to know why.
I mean that seems maybe challenging especially for those of us warm blooded creatures who don't need the sunlight to be able to maintain our body heat.
My name is Sarah, I live in Calgary and I'm 5 and a half wire reptiles are cold blooded.
My name is Evelyn, I'm 6 years old and why are lizards cold blooded?
So that takes us all the way back to evolution, right?
And some animals evolved earlier than others, lizards and reptiles evolved before we did as humans and they were able to adapt to the environment and live in their environment because they were able to generate their own heat from the environment.
They can't get warm on their own but they can lay on a really warm rock and that's why in a lot of cases you can get a snake cross in the road at night time because it's trying to warm up.
I'm Julian, I'm 5, I'm from Houston, Texas and my question is why do lizards constipate their tongue out to their eye and we can't?
My name is Agatha, I'm a 6 year old and I live in California and my question is why do lizards and snakes and other reptiles stick their tongues out very often?
What they eat is what makes their tongue really long.
Being able to touch your eye with your tongue, sure that's kind of cool but being able to touch a fly that's on the branch half way across the room, now that's impressive and that's what a lot of chameleons are actually able to do.
Rocked owls do not stick their tongues out because crocodiles do not have the same type of tongue.
They actually have more like a depressed tongue that is almost solid state and so it's not a movable structure at all and they have an opening at the back of their throat that allows the water to stay out when their mouth is open and then when they're eating that little opening opens up.
They do not have the same functional tongue like we do or like some other cool lizards do.
I'm Luke and my question is how do lizards grow their tails back?
Hi my name is Louise, I am 11 and I live in Fort Collins, Colorado and my question is how do lizards tails grow back?
Hello my name is Linka and my question is one lizard tail falls off wider than you one grow.
I'm Ray Han, I live in Jakarta in Indonesia, I'm 6 years old and my question is, how do lizards grow their tails back?
The types of lizards that can lose their tails have a built-in line of weak spots called a fracture plane along their tail.
When a predator has them by the tail the lizard can actually pull its muscles away from one another and drop the end of their tail that's in the predator's mouth.
Their bodies have also evolved to make sure that they don't lose blood when their tail falls off.
It takes a while to regrow and doesn't always look as good as the original tail, but not all lizards and reptiles can regrow their tail.
Crocodilians cannot regenerate their tail and that's actually how we can tell when they've been in you know perhaps they've been in a fight for some things that we'll get animals that have lost a bit of their tail and because we mark all of the crocodiles and allures that we capture as part of our monitoring project we can see who they are based on the scoots that we've clipped off but they do not regenerate their tail.
Lots of other lizards do.
Unfortunately the gecko that I have at home does not regenerate his tail much to my kiddo's chagrin because mommy caught his tail in the door.
So poor little thing he lost his tail so now he kind of just looks like a long frog but he's super sweet still.
Hi my name is Charlotte.
I'm nine years old. I'm from Oakland New Zealand and my question is is it crocodile dinosaur?
So the common term that we always say is that crocodiles are modern day dinosaurs.
They are the closest thing to what a dinosaur used to be but they're technically not a dinosaur.
In fact dinosaurs and crocodiles and alligators all came from the same ancestor they are called arcosores and from that group we had birds, we had crocodiles and then we have you know things that became lizards eventually.
So they're not dinosaurs but they have been around for so long they might as well be dinosaurs.
Hi my name is Matthew and I am six years old and I live in Selent Beach Florida.
My question is like why did some creatures like lizards and bugs shoot how did they survive like me I say to me here and when dinosaurs just didn't.
So when you think of a dinosaur right you think of like this big lumbering creature.
Super huge. Can't really hide anywhere.
Can't really make itself into a ball.
Can't really do a whole lot to like run away or fly away or get away from something that's coming.
A cockroach something really small can hide in between a rock crevice.
Their babies and their offspring are made into eggs that are super protected.
They have protective cases.
They are super resistant.
So it's just in how they're built they're made to be tough and perhaps the cockroach that we have now it's not the same cockroach that was around back then but they haven't changed very much.
And as for why crocodile ancestors survived when so many other thundering lizard dinosaurs didn't researchers think it may have something to do with the way crocodiles still survive today.
They don't use up a lot of energy because they don't run or swim around much unless they have to which means they can go a long time without eating.
They can also go on land or in the water and they don't mind living in total darkness.
I'm Bryce and I'm five years old and I live in Bidnaani Wisconsin and my question is did crocodiles exist?
Is it when the man is walked?
They were definitely not walking side by side.
Wollimamoths need to be in very very cold places.
Crocodiles, even the ancient crocodiles way back when Dinasukas was actually the very first ancient crocodile.
And to this day crocodiles and alligators or crocodilians as we refer to them they have to be in warm places.
They perhaps lived around the same time but in very different places.
Hi my name is Leo and I want to know what's the difference between alligators and crocodiles.
A crocodile has a V-shaped snout much more pointy and alligator has a U-shaped snout so that's the biggest difference and if you were to look at them from the top down or from the side we always say that a crocodile has a very toothy grin because you can see both the upper and lower teeth whereas in an alligator you only see the bottom teeth.
And then of course the coloration alligators tend to be much darker in color almost black whereas crocodiles can be olive green maybe like a light tan or drab brown and that just has to go with where they live.
They're blending in there it's camouflage alligators live in areas that are marshes dark waters whereas crocodiles are out on the coast or in the estuaries where water is a little bit lighter and in some cases they're on the beach and they're blending in right that way with the sand.
Do all crocodiles live in salt water?
All crocodiles can tolerate salt water but they pretty much all live either very close to fresh water some of them actually like the American crocodile have to drink fresh water to survive whereas the Nile crocodile and crocodiles over in Northern and Southern Africa they have a gland that can secrete the salt so they can actually live in salt water.
So our American crocodile certainly lives along the coast but they need to go up into the estuaries for water.
Here in southern Florida you have both right do they ever overlap are they high five in each other or are alligators and crocodiles living in separate neighborhoods.
So South Florida is the only place in the world where both the American crocodile and the American alligator meet.
The only place that happens and you will see this if you go down to Everglades National Park it's at the very end of the park where the salt water starts to meet the fresh water of the Everglades.
Alligators are in the Everglades in the freshwater system in the marshes coming down through the slews and then in some of the canals that have fragmented the area and then the salt water the coastal areas where crocodiles would be nesting they come up into these areas.
So you will actually be able to see that but that's the only place that they both exist and they exist just fine.
I think they partition the area and the space and they are kind of like just ships passing in the night so they're not hanging out together.
They can hang out beside each other but they're not going to be like major competitors.
They could definitely just hang out.
My name is Spitzer and I live in Utipa, California and my age is six and my question is how do all the data stick to me?
Alligator means in Latin one who binds.
So an alligator when it grabs its prey especially if it's a big prey is going to grab it and wrap around it and then it's going to twist and most of the time they do this underwater.
There is essentially like a way of saying la Certa and lagarto which are in Spanish and it's kind of putting those two together.
So it's alligator sort of came from those two origins.
What about the word crocodile?
Crocodile is actually an ancient Greek word from what they referred to the lizard of the Nile River so it's crocodiles and it's just spelled with a K and it just means lizard.
So that's where the word crocodile comes from which is kind of neat.
Growing up we'll learn more about crocodiles and their very impressive chomping skills.
And do you know what a Nick-titating membrane is?
Stay tuned and you will.
This is But Why, a podcast for curious kids from Vermont Public.
I'm Jane Lintel. Do you hear that?
That's the sound of baby crocodiles calling for their mother.
We've been learning about crocodilians with Venetia Briggs Gonzales, one of the crocodoks at the University of Florida.
Dr. V told us that one of the coolest experiences she has had studying crocodilians was when she got to hold a cluster of baby Crocs for the first time.
She was out in the field counting and measuring them for research so holding the babies was part of the job.
Watching out for a fast approaching adult crocodile who didn't want her to hold the babies was another important part of the job.
Of course you should never pick up baby crocodiles unless you two are part of a research team doing work on them.
Dr. V is answering all the questions you've sent us about these amazing creatures.
So let's learn a little bit now about their bodies, how strong their bite is, and their unique adaptations to their habitat.
My name is Jackson and I'm from San Juan, Michigan.
My question is why do alligators in Toronto have to live in fresh water?
All species, all animals need water to survive in some form or fashion.
And if you're able to survive without fresh water then you have created that adaptation.
So piranhas, sure, they live in fresh water because that's where they were born, that's where they were made to live.
You put them in salt water they're not going to survive.
Crocodiles, same thing when they're little they're in fresh water and they need to be in fresh water, at least the species we have in the US.
Lots of other species can survive in salt water but they have to have special adaptations.
So basically animals usually evolve to live in either fresh water or salt water depending on their needs for food and habitat.
A few creatures have adapted to live in both which is kind of amazing because it usually takes really different bodily systems to process salt water and fresh water.
I'm Elijah and my question is why are alligators teeth so big and their mouth is so long?
Dr. V answered this by talking about crocodiles but it's basically the same thing for alligators too.
A crocodile's way of dealing with the things that it needs to eat is to evolve this longer snout.
So each generation, each snout got a little bit longer and the teeth got stronger because they started to be able to eat bigger things.
More things became available, mammals started coming around, things that have strong heavy bones, they need to be able to break them and tear them really easily.
They're not sitting down at a diner getting a big plate of food and just having everything served to them, they have to be able to hunt it.
So they need to have the tools and for them the tools are like this big strong head with a long snout and really strong teeth, big teeth too.
And why is there a difference then between the snouts of crocodiles and alligators and like you mentioned, garriles that have those long really thin snouts.
So what are the, is there a different prey that they are eating that has caused them to have slightly different jaw structures?
So the jaws and the snout structure for crocodiles alligators and garriles, yes, they're very similar in function, crocodiles, the way they hunt, they are more directed.
So they're going to be hunting, they're swimming, they're hunting.
Alligators are known for being more sit and weight predators, so something comes by they can chomp on it.
When you look at a video of a garril eating, they are slashing through the water, left and right like a sword, left right, left right and so they're getting all the fish that they're slashing through on their mouth is just open and they're kind of like shredding the fish as they're catching it.
My name is David, I'm four years old and my question is why do alligators have eyes that sort of look like meers in the back of them and other aminals like that have that?
Crocodilians, almost all of them have the same thing, it's called a tapetum, lucidum, and what it is, it's essentially like a third eye that these animals have.
It captures the light and it reflects the light almost like a mirror and that's why we're able to see them at night time when we do our work, because we only work at night when we're going out to do captures and surveys because their eyes reflect back red.
It's not that they're glowing red, it's that they're reflecting the light that we're shining on them and it comes back to us as red.
Wow, that is so cool. And that thing that she mentioned that reflects the light back, the tapetum lucidum, that was a new vocabulary word for me.
It turns out lots of animals have a tapetum lucidum, including deer, cats, some dogs, horses, and many other mammals.
It helps with night vision.
Sadly, humans do not have a tapetum lucidum.
My night miss Paddy, my question is how do crocodiles say?
So crocodiles and alligators have eyes that are perched on top of their heads.
So when they're swimming in the water, they can still see out of the water.
When we're in the water and we're swimming, we can't really see above the water and we sure can't see below the water unless we're wearing goggles.
So crocodilians actually have another eyelid and it's called a nictitating membrane, which is super cool.
It kind of protects their eyes when they're swimming and it kind of serves the function of goggles.
So it makes them seem really, really clear and it slides over their eyes when they get under the water and when they come up out of the water, that eyelid just slides away again.
But the way crocodiles and alligators have their eyes on top of their head just allows them to see prey better, to also avoid danger and to be able to escape really quickly.
Yeah, because if you can imagine having eyes on top of your head, you don't have to have much of your body out of the water, but you can still see what's going on and you're kind of hidden, which could be really good if you're trying to catch something.
And I want you to imagine for a minute a nictitating membrane because how cool would it be to be able to dive into a pool or a river or a lake or the ocean and have instead of having to put on goggles, have a little eyelid that comes up and protects your eye from that water, but acts like a goggles so you can see underwater.
I really wish I had a nictitating membrane.
I would love to have one, that would be amazing because we love swimming, right?
And imagine if you had these little tiny goggles that are attached to your eyes and you just turn them on and turn them off by blinking, that would be super cool.
So it's got to be really cool to be a crocodile to be able to do that.
My name is Owen and I'm Peter's O's and I'm a no-fuck-loss trop.
Crocodiles chomp their teeth.
They actually have these really big jaws so they chomp by opening that really big wide mouth and interestingly both crocodiles and alligators are not able to bite open.
They can only close and chomp down.
So a chomping motion is always closing the jaws.
So it has its mouth open before it goes to bite something.
Right. So it'll open it but the strength is the closing motion.
Hello, my name is Daniel.
I live in Potsdam, Pennsylvania.
I'm seven years old and I want to know why do crocodiles have the strongest bite.
For this question, Dr. V turned to her colleague, one of the people she works with, who had been sitting right next to us the whole time.
My name is Dua Ansari and I'm the laboratory manager here at the Crocodogs.
Dua Ansari not only arranged this whole conversation between me and Dr.
V, but she also knows a lot about crocodilians herself.
So yes, crocodiles actually do have the strongest bite and that's because they have the largest jaw closing muscle.
If you're thinking of any animal, any bite, crocodiles take the record.
A thousand percent. I do not want to crock to bite me at all.
I'm Michael and I'm five.
I live in Burlington, Vermont.
I want to know why do crocodiles teeth stay sharp when they don't know how to brush their teeth and they don't have a tooth brush?
Crocodile teeth, they stay sharp due to them constantly feeding because of the type of foods they're eating, the amount of foods they're eating, the frequency of their eating.
Every time they do eat, then it's a little bit of just sharpening or keeping those teeth optimal.
Also, they can feed. Alligators, they shed their teeth and they can actually also replace them.
So this mechanism of shedding and replacing teeth also help in keeping their teeth sharp.
That was one of the questions I had.
Our alligators at all like sharks, which are many species of sharks are known for losing teeth and having a whole new row come in.
It sounds like maybe alligators don't have rows of teeth waiting but they do lose teeth and grow new ones.
Yeah, that's correct. That term is actually called polyphiodonti.
That's another big word at like that one.
My name is Alex. I'm from Mobile World, Alabama.
My question is, why are crocodiles green?
Back to Dr. V. Crocodiles are largely green.
I mean, the color of their skin, it matches where they're living and a lot of them, you know, they all have to be close to water.
Water tends to be more green than it is red or more green than it is blue.
So their skin can change color just a little bit so they can be darker and they can be lighter.
Typically if they're out in the sun and they're basking on the sand, crocodiles are a lighter color or maybe it's a colder day, they can turn a little bit darker to absorb more heat.
My name is Charlie and I'm six years old and I live in Michigan.
I want to know why do crocodiles have to swim?
Sounds like Charlie may have a little sibling who was not as excited to know the answer to why crocodiles have to swim as Charlie was.
Crocodiles are, you know, they're aquatic animals, they're an aquatic species that means they're tied to water and a lot of the things they eat are in the water.
Because we'll eat birds but the birds are close to the water in a lot of cases.
They'll eat mice and rats that are running close to the water or on the shore but the majority of what they eat are fish and things that live in the water.
My name is Pierce and I'm a member of Virginia.
Five years old, my question is how many fish does a crocodile eat one day?
Pierce wants to know how many fish can a crocodile eat in one day.
Thousands of alligators don't eat a lot of food because they are cold-blooded.
If they did not have to regulate their own temperature and spend the energy that they have in their body to warm up their stomach to digest that food, they'd be able to put down a whole lot more.
An average crocodile will eat anywhere from a pound to maximum three pounds per day.
So a crocodile couldn't eat a lot more but it is not able to because it has to take the energy that is running its body to digest that food because it is cold-blooded.
How much energy does it take to track down their food and hunt it down?
You think of a snake. If a snake has just captured something to eat, there's that big ball in its tummy and you can see that ball while it's digesting.
It's going to take that snake several days to digest that.
Kind of like a crocodile, they will eat bigger prey items.
They're just going to take them a lot longer and they're going to be a lot slower.
And while they're trying to digest that, they are not hunting or doing any kind of fast swimming at all.
So if you're lucky enough to see an alligator or a crocodile, they may just be sending themselves just by the water side, right?
They're not always swimming around fast and getting around and doing things and rushing from here to there.
They're kind of seem lazy sometimes.
Most of the time, it's stunning.
It's basking itself. It's trying to keep warm and it's just self-regulating.
On average, you see a crocodile or an alligator swimming very slowly, not going anywhere very fast, but they're watching.
How did you get into this whole idea of spending your life studying crocodilians?
So I have always been fascinated by the outdoors.
And as a kid, I would spend a lot of my weekends and after school time with my parents who were out and about collecting orchids, checking out cool places because I'm from Belize where we have lots of beautiful places.
There's waterfalls and there's creeks and rivers and gorgeous plants and animals just everywhere.
So we spent a lot of time outside and I just fell in love with it.
And as I got older, I wanted to make sure that that stuff stayed around and I learned that there was this whole career in wildlife ecology and that I could be like a doctor, but it would be instead of being a veterinarian taking care of sick animals, it would be taking care of the environment and the ecosystem and making sure that it stays healthy for my kids and my kids' kids.
I kind of like knowing that I can help them just a little bit because a lot of people are afraid of crocodiles and alligators and think that they're out there just to hurt people and they're not.
They could care less about us humans.
They just want to go on about their day, sun themselves, maybe get a little bit of fish and just keep on being.
Wow, I learned so much about crocodilians today and I hope you learned something new too.
After I talked with Dr. V, I drove over to Everglades National Park and actually saw both alligators and crocodiles.
South Florida is the only place in the world where alligators and crocodiles share a habitat so it was really cool to see them just 20 feet apart.
We have pictures up on our social media channels if you want to get an adult to help you take a look at them.
Thanks to Venetia Briggs Gonzales and Dua Ansari of the Croc Docs at the University of Florida for sharing awesome knowledge of Crocs and Gators with us.
Now if you have a question about anything, have an adult help you record yourself asking it.
Then send the file to questions at butwhykids.org.
We need your first name, where you live and how old you are and what your question is.
You can also check out our website but whykids.org for full instructions.
I wish we could answer all of your questions as quickly as you ask them but there's only three of us working on but why so we can't get to them all.
Still, I love knowing what you're curious about and if you ever have a question and then you wind up going and doing the research to find the answer yourself, send us a video and we'll put it up on our Instagram page.
Those three people I mentioned that make butwhy?
They're me, Jane Lindholm, alongside Melody Bodette and Keana Haskin.
Lots of other people help us make sure this show gets out to you all, including Vermont public where we make the show and PRX which distributes it.
And of course, you recognize that music when we start the show that tells you, hey, but why is on?
That was created by Luke Reynolds.
We'll be back in two weeks with an all new episode.
Until then, stay curious.
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