Episode 5: The Aldabra Giant Tortoise with Nate Nelson

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INTRO (00:00)

*Intro Music – you and me the adventure, me and you to the zoo*

EMILY BISHOP: Hello, and welcome to the Sedgwick County ZooCast, where we are inspiring respect and conservation for wildlife and wild places through caring, connecting, and conserving.

I’m your host, Emily Bishop, and today on the ZooCast, we’ll be sitting down with Nate Nelson, the Curator of Ectotherms, to talk about The Aldabra Giant Tortoise.

Keep listening to learn what an “ectotherm” is, the difference between a turtle and a tortoise, and how our zookeepers move a 500-pound reptile when it needs to go inside.

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INTERVIEW WITH THE CURATOR OF ECTOTHERMS, NATE NELSON // LEARN ABOUT ALDABRA GIANT TORTOISES (00:45)

BISHOP: Thank you so much for joining us today on the ZooCast.

NATE NENSLON: Sure. Good to be here.

BISHOP: Yeah, if just to get started you could just give an introduction, talk about who you are and what it is you do here at Sedgwick County Zoo.

NELSON: All right, well, I’m Nate Nelson. I’m the curator of ectotherms here. I’ve been here since 2006. Actually, this month marks 17 years. So, my duties incorporate the health and welfare of the reptiles, amphibians, the fishes, the invertebrates, and all the exhibits and facilities that go with that.

BISHOP: How did you become the curator of ectotherms? And also like, what does that job title mean?

NELSON: Well, I didn’t plan on working in the zoo field. I went to school to be a conservation biologist. And as I finished grad school, I needed a full paying job. My wife insisted on it, actually. And so, I ended up taking a zoo job, ended up loving zoos, and I just sort of have been at it ever since. So, I came here as a zoological manager in 2006. And then the curator retired, I became curator.

BISHOP: And for people who maybe aren’t as in the know, what is an ectotherm?

NELSON: Well, ectotherm is an animal that cannot control its body temperature. Like, we’re warm-blooded animals, birds, mammals are warm blooded animals. Ectotherms are cold-blooded, as it’s called. They rely on the environment to either heat up or cool down.

BISHOP: So, how did you first get started working with the Aldabra giant tortoise?

NELSON: Well, like I said, I came here as a zoological manager, and we had four giant tortoises in the collection. So that’s- it was really as simple as that.

BISHOP: So, what differentiates the Aldabra giant tortoise from other tortoises?

NELSON: Well, what immediately distinguishes them from all the other tortoises in the world is size.  Other than the Galapagos giant tortoises. It’s sort of neck and neck who’s the bigger one, most people agree Galapagos are a little bigger. But Aldabs are right there with them. And, to me, what distinguishes Aldabs and makes them interesting to me is they’re so peaceful and communal compared to all the other turtles. Especially when you look at turtles as a whole, most of them are territorial, they’re solitary, you can’t put two males together. Oftentimes, you can’t put two females together, they’ll squabble. They’ll fight, sometimes seriously. And Aldabs kind of just went the opposite direction. They’re this very peaceful communal, there’s little to no agonistic behavior between them. So, it’s not uncommon to walk by the exhibit, for instance, and you’ll see all six of our animals just huddled, close together, touching,

BISHOP: Just hanging out?

NELSON: Just hanging out.

BISHOP: What is the difference between a tortoise and a turtle? Or are those terms kind of interchangeable?

NELSON: Oh boy, if I had a nickel for every time I’ve been ask this.

So, the simple answer to the question is, all tortoises are turtles. If you want to know why that is, we have to kind of get into the weeds because there’s a few different reasons why that is. When guests asked me that I kind of say something along the lines of, “well think of it like what’s the difference between an owl and a bird? Owls are birds, we just decided to call a group of birds, owls.” Scientifically we leave tortoise for a family of turtles that tend to have a high shell, adaptations to arid environments. They kind of have clubbed feet, and they live on land.

But if you travel abroad, and you go to somewhere like the UK or Australia or New Zealand or South Africa, they have a whole cultural reason. They tend to call everything a tortoise. If it’s freshwater, they might call the terrapin. And so, there’s a lot of confusion out there but strictly you can get away with saying all tortoises are turtles

BISHOP: At the Sedgwick County Zoo, our Aldabra giant tortoises can be found at the Amphibians and Reptiles building. But where are these tortoises found in the wild? And what does their natural habitat look like?

NELSON: Okay, well, one slight correction. Our biggest Aldabra tortoise is actually too big for the Amphibians and Reptiles building. So, he’s over with our Galapagos tortoises on the other side of the Zoo.

But they come from what’s called the Aldabra Atoll in the Indian Ocean. It’s kind of between Madagascar and the Seychelles Island Chain. And it’s- it’s a small raised coral reef with a big saltwater lagoon in the middle of it. It’s only about 20 miles long, maybe about one to two miles wide. So, it’s pretty small. And when you consider there’s probably 100,000 – 120,000 tortoises on it. They’re very, very dense. There’s a lot of them on there. And it’s tropical. It’s pretty much right on the equator, very hot. There’s no freshwater, there’s no rivers, there’s no creeks, the only freshwater there is what comes with the rain.

BISHOP: What role are these tortoises playing in their environment?

NELSON: Well, they pretty much dominate the terrestrial environment of the Aldabra Atoll. They’re the biggest animal, they cause the most grazing on the plants, they pretty much shaped the whole ecosystem there. Without them, I think the islands would look entirely different. There’re entire papers that have been written on exactly what the tortoises have done to reshape and make unique ecosystems there on the Atoll.

BISHOP: Now, these are one of the only giant tortoise species left in the wild.

NELSON: Correct. You know, with the Galapagos Islands, they’re actually splitting those tortoises up into many separate species now.

BISHOP: Oh, okay.

NELSON: And we used to think they were all one but when we look at the genetics, we can see that even on one island, some of the turtles never interbred, and they’ve sort of speciated away from each other. On Aldabra, genetically, they’re all pretty much the same, but people have moved those around. So, there’s now Aldabra- wild Aldabras on the Seychelles Islands. They’re in Mauritius. They’re on Rodriguez and a couple of the other islands. Historically, it’s thought that pretty much all the Indian Ocean Islands had a giant tortoise at one time that- it’s gone extinct for one reason or another. Could be manmade extinctions could be other things.

BISHOP: So, how many Aldabra giant tortoises do we have here at SCZ?

NELSON: So, we have seven. We’ve got four males, three females.

BISHOP: Can you tell us a little bit about them?

NELSON: Well, they’re big. So, Rocket is probably the most famous one. He’s- he came to the Zoo in May of ‘72. And so, he is the oldest animal here at the Zoo. He’s 91 years old this year. And he was here before any of the other animals at the Zoo. He’s been here the longest. Technically, he went away for several years because we didn’t have a space for him. But he predates Stephanie the elephant by a few months and Sweetie Pie the hippo by a few months. So, he’s the most well-known.

There’s been several press articles about him, going up to the Bronx Zoo, coming back, etc. His penchant for busting through gates and escaping has been a subject for the public. The other two females, Missy, Speed, they were also purchased by other zoos around the same time and came to us one way or another. Same with Washington. And then we have three new ones- newer- that came to us in 2021 from a wildlife rehab center down in Oklahoma.

BISHOP: Do you notice, like, distinct kind of like personalities and behaviors in each of the tortoises?

NELSON: Yes, I mean, for the most part, they act pretty much the same. But if you’re a keeper and you’re with them day to day, you’ll- you’ll see little individual quirks and idiosyncrasies that they each have. Some are more stubborn than others, some are more apt to come walking to you and get scratched on the neck and so on, so forth. But I think for the average person, they won’t see different personalities just as a guest, as a visitor.

BISHOP: Yeah. Can you elaborate a little bit on the tortoise personalities?

NELSON: Well, like I said, some are much more food motivated than the others. Some are much more scratch and touch motivated than the others, more outgoing. For instance, if I walk up to Rocket or Speed- Speed’s definitely the most extroverted of the group. He’ll see you across the yard, and he’ll just immediately start walking over to you. The others will sort of study you and see if you’re feeding and then they might walk over, and so forth.

BISHOP: So, how old are all of our tortoises?

NELSON: So, Rocket’s the oldest at 91. And we estimate Noble, who came from Oklahoma, to be about 15. So, we got a group of three teenagers, essentially. And then a group of four that range from 56 to 91 years old.

BISHOP: Do you have any tips for how you can maybe tell the tortoises apart? If you were to come to the Zoo and look at them?

NELSON: Yeah, so they all have an- a unique individual shell shape that you can pick up on pretty quick. Two of the animals, Bainbridge and Galena, look very, very similar to each other. So, it really is hard to distinguish them I think for the public. Galena has a slightly taller shell than Bainbridge when you look at them in profile, otherwise, they look identical. The other ones have very distinct shell shapes. So that’s how we tell them apart.

BISHOP: Can you talk about conservation efforts for the tortoises?

NELSON: Yeah, so there isn’t a whole lot of conservation going on with Aldabra tortoises because the Aldabra Atoll is a protected World Heritage Site already. Owned by the Seychelles government. So, the only population of people there is a research lab on one of the remote islands. And so, they’re pretty much stable where they exist. And like I said, estimates go anywhere from 80,000 to 120,000 tortoises at any one time. So, they’re not endangered at this point. And plus, like I said, there are introduced populations on other islands now too, so there really is no need for conservation in that respect.

BISHOP: Yeah. So, they’re doing all right.

NELSONG: They’re doing okay.

BISHOP: That’s good to hear.

So, if listeners at home- well, I guess, like, conservation isn’t a huge thing for the tortoises, specifically. If they wanted to aid maybe in conservation, within some of the habitats and islands that these tortoises are found on, is there anything that they could do?

NELSON: Yeah, I mean, you could look up several Seychelles Nature Foundations, and probably donate to island conservation that way directly to Aldabran tortoises. Otherwise, you’d have to look at other species like Galapagos tortoises and radiated tortoises and stuff that really is of conservation need.

BISHOP: Is it just because the Aldabras are found in such a-a smaller range that they’re less threatened than other giant tortoises?

NELSON: No, it’s- it’s kind of curious as to how come they did so well, when literally every other island lost their giant tortoises in the last, you know, 500 to 1000 years. I don’t know why. Maybe Aldabra, you know, just wasn’t on the shipping routes that a lot of the European sailors used. You know, we do know that European sailors did come to the Atoll, and they did take Aldabra tortoises, they kept him as a source of food, long term on ships, you know, for the spice trade routes and stuff like that. But as to why they didn’t get decimated like the rest. I really don’t know.

BISHOP: Just lucky I guess.

NELSON: Yeah. A big part of that maybe because cats and rats may have never made it, or goats never made it to the Atoll. So, those are the main reasons. The main competitors with giant tortoises in other locations: cats, rats, goats,

BISHOP: In what ways are cats, rats, and goats competing with other tortoises?

NELSON: Well, rats are eating the eggs. They’re eating the hatchlings. Cats are eating the hatchlings. And then goats are competing directly with them for the vegetation to eat.

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LEARN ABOUT ZOOBILEE (12:42)

BISHOP: We’ll be back in a moment to learn more about the Aldabra Giant Tortoise. But first, let’s hear about an upcoming event at the Zoo.

Welcome to Wichita’s wildest FUN-raiser.

Enjoy live music, delicious drinks, and delectable bites from local establishments during Sedgwick County Zoo’s premier fundraiser. Zoobilee raises funds that help keep the Sedgwick County Zoo animals fed and admission prices affordable. A portion of the funds raised at the event also go to support the Zoo’s animal conservation initiatives in the wild.

Saturday, September 9^th from 6pm – midnight, you won’t want to miss Zoobilee.

Visit scz.org for more information.

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WHAT DO SCZ VISITORS THINK ABOUT ALDABRA GIANT TORTOISES? (13:29)

BISHOP: The great thing about the Sedgwick County Zoo is that not only are we a place with a passion for conservation and education, but we also have a passion for community. It’s a great place to socialize.

So, the Sedgwick County ZooCast team took to the streets to ask visitors what they thought about the Aldabra giant tortoise.

VARIOUS GUESTS:

I just like their faces. I think they look goofy.

The size is pretty impressive, that they can still move around being that large.

Um, because them have a shell.

I’ve always liked turtles and tortoises. So, I just think they’re cute.

My favorite thing about the tortoise is how old they can get and still move pretty effectively for how slow they are.

A turtle… tortoise… they’re friends.
They’re friends?
Friends.
Yeah. Hey, what do turtles have on their back?
Ummm ummmm
A shell?
Shell
They have a shell?
Yeah.

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ANSWERING QUESTIONS FROM THE AUDIENCE (14:41)

BISHOP: So, now we have some questions from the audience. And these questions were all submitted to us through our Instagram @SedgwickCountyZoo.

So, @ApolloDaWoof wants to know, “how big do they get?”

NELSON: Well, that’s a kind of a loaded question. It really depends on their genetics and which island on the Atoll they came from. Different populations reach different sizes. The maximum you’re gonna get is, you know, that I’ve heard was somewhere in the 700s- that’s a really exceptional animal. Seven-hundred pounds. In zoo’s a really big animal, you’re- if you see one, it’s going to be 500 to 600 pounds,

BISHOP: How big is Rocket, our biggest one?

NELSON: So, when we sent Rocket away, originally back in, I believe 2008, he weighed right around 610 pounds. But you have to account for, you know, plus or minus error on the scale and things like that. These days when he- after he came back, he weighed about 525 I think.

BISHOP: How small is our smallest tortoise?

NELSON: So, our smallest tortoise, Noble, the 15-year-old, he’s about 151 pounds.

BISHOP: Okay, so that’s quite a range between.

NELSON: He’s got a quite a bit more growing to do.

BISHOP: Yeah. At about what age are they like, mature?

NELSON: So, they seem to reach sexual maturity in their late teens, early 20s. And a lot of that is kind of unknown. You know, it’s not always apples to apples, how they behave in zoos in the northern hemisphere versus how they reach maturity in the wild. So those- those studies on them in the wild aren’t always applicable to what we see in zoos, but in zoos, it seems like the younger animals in their teens and 20s and maybe 30s are reproductive. Whereas, say our animals, we have our females are their 60s and 70s. We’ve never seen them lay eggs. We think they’re post reproductive

BISHOP @AidanOzHarris wants to know, “how fast can they go?”

NELSON: Faster than you think. They’re pretty quick to step on a hose or get in your way, even though you know, technically they move slow. I don’t know what miles per hour is on them, but faster than you want or slower than you want depending on what you want seems to be how it goes with those.

BISHOP: You just can’t win

NELSON: Can’t win, no

BISHOP: Gonna- never gonna move at the speed you want.

@Makaveli1371 asks, “what is their average age?”

NELSON: Well, again, we have two complete different ends of the spectrum, we got a 91 year old and a young one at 15. In the wild, it’s still kind of unknown exactly how long they live. There are reports of animals living 255 years.

BISHOP: Oh, wow.

NELSON: But a lot of those aren’t really verifiable. But we know pretty well that there’s at least one out there that’s about 190 years old.

BISHOP: @Putter7715 asks, “do their bodies fill their entire shell?”

NELSON: Yes. So, for people who don’t know much about turtles and tortoises, you know, some people think they can switch shells like a hermit crab. They can’t. The shell is a living part of their body. It’s bone and cartilage and it’s covered with keratin like our nails or hair. And yeah, it’s completely filled with organs and lungs just like us.

BISHOP: Yeah, so some turtles I know, like, they’ll kind of pull their heads into their shells. And the Aldabras, do they do that or no?

NELSON: Yeah, they can do that. They’ll- if they’re really feeling scared, they’ll pull all the legs in and the head

BISHOP: Oh so, totally all the way in the shell. Okay.

NELSON: It takes a lot to scare our group they’ve pretty much seen it all and yeah, pretty calm

BISHOP: They’re not impressed

NELSON: Not impressed.

BISHOP: @Misha.Y.Harmon asks, “how much time do they spend in the water?”

NELSON: Well, like I said, in the wild, they really don’t have natural water sources. Running water of any kind. When they do get water it’s puddles from rainstorms. And it just depends on how fast that evaporates off. We give them a- comparatively a really big deep water source, which the older ones use. The young ones still have never willingly got in the water.

BISHOP: They’re not interested in it.

NELSON: Right. So, like, say this morning. I walked out there and saw them first thing and our two females were in the water the male was climbing out, but the three teenagers were nowhere near it. So, they get in there I think mostly for you know, cooling down. It’s thermally a little cooler than outside. They’ve learned that over the years. But the new ones haven’t caught on yet.

BISHOP: @_JessicaCuellar_ asks, “how is Missy’s health and do you give her special care/diet since she was born around 1950?”

NELSON: Missy’s health is good. So, she does have two cataracts and so we manage her a little differently. We make sure that when we give food, we place some food directly in front of her because she seems to have some distance sight issues these days. But otherwise, she’s very healthy.

BISHOP: @LavishPrairiePhotographer wants to know, “are the tortoises able to breed or are they too old?”

NELSON: Well, again, this is a matter of discussion. I think not just with us with others zoos too. In what they see in their Aldabra tortoises, I would guess that our animals are a little too old. Now, they will still attempt to breed, the males will still try to breed and you see that all the time in the outdoor exhibit, but like I said, we’ve never had eggs. We’ve never seen any indication that this can happen with a group.

BISHOP: And we don’t have any kind of like, breeding recommendation?

NESLON: We don’t, yeah. They’re not a managed species in AZA zoos. Like I said, there’s no conservation value necessarily in them. Their value is just how big they are. And they’re- they can be an ambassador for other giant tortoises.

BISHOP: So, it’s more so like, if they happen to successfully mate and have eggs, great. And if not, like, we’re not worried about it.

NELSON: Yeah. No, we would be elated if they had eggs, and we could hatch out some baby Aldabras, but doesn’t seem to be in the cards so far.

BISHOP: @McKenzieKramer3 three asks, “do you have to give them baths?”

NELSON: No, we don’t. They pretty much wash themselves as needed. And they sit out in the rain and get washed off. Now when they’re indoors for the winter, in the indoors exhibit, the keepers have to, you know, clean the exhibit with them in there. And of course, they get washed off all the time with the hose- intentionally or not. They’ll walk through the hose spray. And so, we don’t want to actually set out to bathe them.

BISHOP: It just kind of happened.

NELSON: It just happens.

BISHOP: @JakobeWithSideBurns wants to know, “what the difference between the Aldabra giant tortoise and the Galapagos tortoises are?”

NELSON: Right. So, I think to the average visitor to looking at them, there’s not much difference at all. The major difference obviously, is one’s from the Galapagos Islands off the coast of South America and the Pacific Ocean than the other ones from the Indian Ocean off the coast of Madagascar. But otherwise, it’s very, I would say, you know, very minimal characteristics that the average guest would be able to see. One’s called the nuchal scute in the middle of the shell right above the head. It’s a tiny little part of the shell that the Aldabras ave in the Galaps don’t. The Galaps have a different head shape too, but unless you’re seeing them side by side, it’s really hard to explain to somebody.

BISHOP: @Lilith.A.F wants to know, “are any of the tortoises in love?”

NELSON: Not that we’ve seen. I think Speed loves all the other tortoises, but not in the way that mammals do.

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LEARN ABOUT WILD LIGHTS (22:24)

Before Nate and I finish our conversation about the Aldabra Giant Tortoise, let’s learn about upcoming events at the Zoo.

Follow the white rabbit to a land of wonder at this year’s Wild Lights.

Come face-to-face with One-of-a-kind Asian lantern sculptures. Maybe a Cheshire cat will cross your path, or the queen’s guard of playing cards. Be the guest of honor at a tea party hosted by a hatter and a hare.

Wednesday through Sunday – October 11 through December 17 from 6 p.m. to 9 p.m.

Tickets start at $15 and are available online or in person.

Journey through the looking glass at Wild Lights.

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CLOSING THOUGHTS ON THE ALDABRA GIANT TORTOISE (23:15)

BISHOP: Wrapping things up I just have a few more questions.

What is your favorite thing about working with the Aldabra giant tortoise?

NELSON: Well, I mean, not many people get to work with giant tortoises. So, it’s just cool in and of itself. And it’s- it’s always kind of fun to manage with them. And, you know, plan ahead for when they’re going out when they’re coming in. It’s just a different management strategy than all the other turtles and tortoises we have.

BISHOP: What’s the most common question you’re asked by guests?

NELSON: When I think about what the average questions I get from the guests about Aldabra tortoises, it’s things like, “why are- why aren’t they outside right now?” But a guest may come here on an 80-degree day. And the tortoises are inside. And they’re like, “what’s going on, why aren’t the tortoises outside enjoying the sunshine?” And the reason for that is probably because it’s gonna get way too cold at night. And so, they have a temperature cut off at 55 degrees. And we can fudge that on some nights if it’s gonna get 54-55. But the next day is gonna get back into the 80s, then we might leave them outside. But if it’s going to be 55, and then a high of like, 65 the next day, that’s too cold for them long term. And you’re really rolling the dice there with their health with those kinds of temperatures.

So, I understand people are frustrated, they come on the sunny day and the tortoises aren’t out. And that’s why we- we definitely have to manage them. And people forget, don’t realize that, you know they’re from the tropics. They’re right on the equator. They’re truly tropical tortoise and we kind of push the limits with them being in a place like Kansas with our extremes of weather.

BISHOP: What kind of things do you do to help them adapt to when it’s like really cold and then adapt to when it’s super-hot?

NELSON: Well, there’s really with an ectotherm, there’s no adapting to it, it is what it is. So, we have to get them in. And that can be really challenging with Kansas’ weather because I mean, we have extremes of- what we hit -7 last winter? And we’ve hit 107 this summer. And then we have severe weather in between. So, one of our biggest concerns is hail storms, because if a hail storm rolls through, it could really hurt them. And it’s not easy getting, you know, hundreds and hundreds of pounds of tortoises inside. Because they don’t… they don’t watch the forecast. And, you know, if they want to be outside, they want to be outside.

We’ve tried training them, tried to get them for years to come in when we want them to come in. And we’ve had limited success. But generally, I find if we want them to come in, a couple might- a couple may just decide no, they don’t care about the carrot or the apple you’re offering them. They’re gonna sit right there, and you have to manually move them inside. So that’s kind of an all-hands on deck thing when a thunderstorm just pops out of nowhere. We have to go grab them all and get them inside for their safety.

BISHOP: How do you manually move the tortoises?

NELSON: We have to pick them up.

BISHOP: Just like a group lift effort?

NELSON: Group lift effort. And try that with a 520-pound tortoise.

BISHOP: I can’t imagine

NELSON: Who doesn’t want to go.

BISHO:  Yeah. So, I know like when it’s cold, or they have to be inside. You ever bring them in because it’s too hot out? Or like, as long as it’s warm, they are fine?

NELSON: No, they’re fine. As long as they have shade. So as long as they have shade and can kinda stay out of direct sunlight. They’re fine.

BISHOP: What is your favorite thing about the Aldabra giant tortoise?

NELSON: Well, again, to me, it’s just interesting because we have a lot of different turtles and tortoises here at the Zoo. And again, most turtles are solitary. When you walk by our exhibits in the building, you’ll see one maybe two turtles and there’s a reason for that because we can’t put a lot of turtles together. And Aldabrans are just so different in that respect that they actually seek each other out. You can give them the biggest yard and you’ll find them all huddled together in the same corner every day. They like to touch each other they like to be- they’re really like a herd animal, which is so different than all the other turtles.

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OUTRO (27:17)

Thanks for listening to the Sedgwick County ZooCast.

This episode was researched, written, and produced by me- Emily Bishop.

We’d like to give a special thank you to Nate Nelson, for sitting down and talking with us about the Aldabra Giant Tortoise.

Thank you to the Sedgwick County Zoo’s Marketing and Communication Team

And a special thank you to our Zoo Members, whose support makes this podcast possible. If you’re interested in becoming a Zoo Member, visit scz.org/membership.

Be sure to give us a follow so you never miss when we upload new episodes.

Thanks again for listening. Until next time, I’m Emily Bishop and this has been the Sedgwick County ZooCast.