Welcome to brain Stuff, a production of iHeart Radio. Hey brain Stuff, Lauren Vogelbaum. Here, at some point, let's just say around two hundred and sixty million years ago, Earth got turtles. They look strange in these our modern mammalion times, when lots of things are squishy and unarmored, But during the Late Permian epoch, those early turtles were dressed in all the latest fashions, short sturdy legs, bony plates, and
a stiff splayed crawling strut. Shortly after turtles made their evolutionary arrival, a fairly standard Earth thing happened a mass extinction event. Although mass extinctions have happened with some regularity on our planet, this one was a doozy, and it wiped out almost all of the life in the oceans and over two thirds of the vertebrates on land. The things that survived had to have been pretty good at survival,
and it turns out turtles were. But we spoke about email with Laura Smith, a research scientists who specializes in herpetology at the Jones Center at ITUA, which is an organization in Newton, Georgia that promotes excellence and natural resource management and conservation. She said, turtles have a really successful body form that hasn't changed all that much over time. They've retained the primitive shell, which is a really protective, safe body design. Also, turtles live in a lot of
different habitats. They're aquatic and also terrestrial, so living in a lot of different habitats has allowed them to persist. So well, what's the difference between tortoises and turtles. All of the animals alive today that protect themselves with a shell, which is basically just a modified rib cage, are in
the order test studinies. Collectively, we call this group of animals turtles, but individually we might call them different things based on where they live and some morphological and physiological traits. Hortoises are a group that are generally always found on land. Smith said, they say that not all turtles are tortoises, but all tortoises are turtles. The turtles are organisms with a shell which might be in water or might be
on land. A tortoise is a type of turtle. In general, both turtles and tortoises, as well as other reptiles, lay their eggs on land. It's what makes them different from amphibians, which need water for egg laying and at least part of their life cycle. Because tortoises are a type of turtle, it's difficult to lay down hard and fast rules about
what makes something tortoises rather than turtle ish. But in general, tortoises are always found on land, whereas turtles can be found in aquatic or marine habitats as well as land. Smith said turtles and tortoises look different because of where they live. A sea turtle is only found in the ocean. The females are the only ones that come on land, and that's just to lay eggs. They have four legs, but the front legs are almost like wings or paddles.
They're not great for moving around on land at all because they're adapted for swimming quickly. Their shells have a low, flat profile for cutting through the water. Compare that to a Galapa ghost tortoise, for example, whose body can weigh up to nine d and twenty pounds that's almost four d and twenty kilos. With stocky, elefantine legs, a high domed shell, and big scales on their exposed skin to protect them from predators, they wouldn't last long in the ocean,
but luckily they don't have to. The Smith said, for the most part, there's not really one characteristic that tells you whether something is a tortoise or a turtle. But it's pretty clear. If you see a little turtle on the side of the road and it has a sort of flattened shell profile, webbed feet in the back, smooth skin, and some brighter colors, that's going to be a turtle. The tortoises have a heavier, more domed shell and subdued colors.
As usual, the terminology can be confusing. Box turtles, for instance, which are widespread in the United States in Central America and don't really swim or spend much time in the water, but they're still considered turtles rather than tortoises. And then there are the terrapins, which is the name given to aquatic turtles in the United Kingdom. In the US, aquatic turtles are just called turtles, with the exception of the diamond back terrapin, which lives in brackish water in tidal
marshes in the eastern United States. Both tortoises and turtles have made themselves at home on this planet. We find both on every continent other than Antarctica. With one exception, there are no tortoise species native to Australia. Smith said the greatest diversity of aquatic turtles are in Southeast Asia and in the southeastern United States. The greatest tortoise bio
diversity is in South Africa. And there used to be more giant tortoises across the world, but now there are just remnants on the Galapagos and Aldebra places like that. Giant tortoises do occasionally disperse, or more likely drift across oceans, basically by surviving for weeks or months bobbing around. In recent years, an aldebrand tortoise with barnacles on its shell washed up in East Africa, and that's not bad for
something that started its life in the Indian Ocean. Today's episode was written by Jesceline Shields and produced by Tyler Clang. For more on this and lots of other curious topics, is it has to Works dot Com brainstuff this production of iHeart Radio. For more podcasts from my heart Radio, visit the iHeart Radio app, Apple Podcasts, or wherever you listen to your favorite shows.