Animals Wildlife 5 Surprising Facts About Salamanders By Jaymi Heimbuch Writer California Polytechnic State University, San Luis Obispo Jaymi Heimbuch is a writer and photographer specializing in wildlife conservation. She is the author of The Ethiopian Wolf: Hope at the Edge of Extinction. our editorial process Twitter Twitter Jaymi Heimbuch Updated May 31, 2017 A salamander on the ground. MF Photo/Shutterstock Share Twitter Pinterest Email Animals Wildlife Pets Animal Rights Endangered Species The oldest salamander species rubbed elbows with Jurassic dinosaurs. A 157-million-year-old salamander fossil discovered a few years ago in China is the oldest of its kind and places this ancient species as living with Jurassic dinosaurs. It is thought that salamanders diverged from other amphibians somewhere around 200 million years ago. Who knows what future fossil discoveries may reveal! The Mexican salamander or axolotl stays forever young. Unlike other salamander species, the unique and critically endangered axolotl keeps its juvenile features into adulthood. "This condition, called neoteny, means it keeps its tadpole-like dorsal fin, which runs almost the length of its body, and its feathery external gills, which protrude from the back of its wide head," writes National Geographic. North America has more than 150 salamander species. North America is home to more species of salamander than any other region on the planet, with likely still more species yet to be discovered. If that sounds like a lot, it is. In fact, an estimated 48 percent of all known salamander species live on North and Central America, according to Discovery News. "They range in size from the diminutive 2-inch pygmy salamander, found in spruce-fir Appalachian forests, to the 2- to 4-foot-long two-toed amphiuma, a ditch-dwelling Southeastern species that resembles an eel," writes Terry Krautwurst on Mother Earth News. Giant salamanders grow to over five feet long. There are several species of giant salamander, and they're considered the largest amphibians in the world. The Chinese giant salamander is the largest and can reach lengths of 5.9 feet. Though it can reach that length, the average size is 3.77 feet. Still, that's one big salamander! Meanwhile, the Japanese giant salamander can reach lengths of nearly 5 feet. Sirens are salamanders that have both gills and lungs (and no hind legs). There's a whole suborder of salamanders called sirens. But they don't lure you closer with their songs — though two species can produce vocalizations. Instead, they lure you in with their oddball cuteness. They have eel-like bodies with tiny vestigial front legs and no hind legs. And also unlike (most) other salamanders, they have external gills even in adulthood.