Axolotl, a Mexican salamander that retains most of its larval characteristics, but which matures sexually and is able to reproduce. This ability to reproduce without attaining adult form is called neoteny. Axolotls were first known in the lakes around Mexico City, and were given their name by the Aztecs. They look like the larvae of the tiger salamander, a closely related species. Axolotls are sold in Mexican markets as food.

Neotenic tiger salamanders, often confused with axolotls, are occasionally found in Texas, Kansas, and Oklahoma, and in the Rocky Mountains. In most parts of the United States, however, the tiger salamander attains adult form.

The axolotl is Ambystoma mexicanum; the tiger salamander is A. tigrinum. Both belong to the family Ambystomatidae.