The axolotl is an amphibian. It is also a type of salamander. Its name comes from Nahuatl, a language of the Aztecs. An axolotl lives in the water for its whole life. Axolotls are neotenic. That means they keep young traits when they are grown. They never grow up to become adult salamanders. An axolotl has feathery gills on the outside of its head. The gills are for breathing underwater. Grown axolotls have working lungs as well as gills. They can also breathe through their skin.

Wild axolotls are mostly dark. They are black, brown or gray. An axolotl can reach about 12 inches long. It hides in mud and plants during the day. It is active at night. It eats worms, insect larvae and small fish. It catches food by sucking it in. It may suck up gravel too. The gravel helps grind up its food.

An axolotl can grow back a lost leg. This can take a few weeks to months. It can also grow back hearts and parts of the brain. After an injury, a mass of cells called a blastema forms. The blastema can grow back the missing part. Axolotls also heal wounds without forming scar tissue. For this reason, they are a common research subject for biologists.

Axolotls come from lakes and wetlands. These are in southern Mexico City, in Mexico. They once lived in a series of lakes in the Mexican Central Valley. Many of those lakes have been drained. This was done to reduce flooding. The biggest threats are urbanization and pollution of their lakes. Fish put into the waterways compete with axolotls for food. Fish such as tilapia and carp also eat their young. Storks, herons and large fish sometimes eat axolotls. More farmers are using traditional farming. This kind of farming is free of pesticides and fertilizers. It helps to conserve axolotls.

Words to know

• amphibian: animal group
• neotenic: keeping young traits
• gills: breathing parts
• blastema: mass of cells