The Axolotl Salamander Doesn't Wanna Grow Up
Native to the lakes of Mexico City, the axolotl stays in the water its whole life, swimming with a tail fin and breathing through frilly external gills. It’s nearly extinct in the wild, but survives in research labs the world over, studied for its amazing regenerative abilities. With our help, can these beloved creatures thrive once again in their ancestral home?
TRANSCRIPT
The axolotl isn’t just a frilly salamander with a half-smile and a blank stare.
It’s named after an Aztec god, who escaped death by morphing into this amphibian shape.
It’s a creature that’s a bridge between worlds: the spiritual and the natural; the aquatic and the terrestrial; survival and extinction.
Like most of its salamander relatives, the axolotl begins its life as a tiny, translucent egg laid underwater. It grows into a tadpole — a larva with gills and a flattened, fin-shaped tail. In time, many salamanders shed these features, develop lungs, and crawl onto land. But the axolotl never makes the transition ashore. Even as it grows — up to a foot in length — it hangs on to its larval lifestyle.
The gills are reddish-purple from the blood cells pulsing through them, pulling oxygen directly from the water. To breathe, it just flaps those gills.
But if that doesn’t work — like if there’s not enough oxygen in the water — the axolotl has a backup: fully functional lungs it can use to gulp air from the surface. These organs are evolutionary leftovers from when its ancestors lived on land. The axolotl’s lungs are a rare example of cryptic metamorphosis — when an animal matures to its next stage of development internally, but doesn’t show it on the outside.
Despite its flexibility, this magnificent vertebrate is in trouble.
Since the 16th century, the axolotl’s native habitat, Lake Xochimilco in Mexico City, has been built over and polluted as this megacity grew. Now the lake is just a few canals, where the axolotls battle invasive predators, and warming waters from climate change. Here, in the remnants of their ancestral home, only a few hundred are left.
But scattered across the globe, you’ll find thousands of them — not in the wild though. They’re in research labs. Scientists are impressed by the axolotl’s ability to rapidly regenerate damaged limbs, organs, even parts of their brain. And that’s amazing for a vertebrate — an animal with a backbone — like us. Harnessing this healing ability for humans would be a breakthrough.
But what does it mean if an animal is thriving only in captivity?
What is a species without its natural habitat?
To preserve what’s left of the axolotl’s wild home, a team of biologists at the National Autonomous University of Mexico started an innovative collaboration. They work with farmers of the chinampas — the traditional floating gardens along the Xochimilco canals where the animals still live.
The farmers filter canal water for crops through native aquatic plants and gravel, without the use of pesticides. This protects axolotls from both pollution and invasive predators.
For many in Mexico City, axolotls have come to symbolize the connection between humans and the natural world.
Humans have put axolotls and our environment in peril. But with traditional knowledge, respect, and some ingenuity, we can give these remarkable animals a chance to come back.
Hey Deep Peeps, It’s Laura. Can you find your friends in a crowd as well as a baby penguin? Sense Earth’s magnetic field like a fox? To find out, watch PBS’ brand new show, Animal I.Q.! Head on over to PBS Terra to see it, and tell them Deep Look sent you. Have fun!