The axolotl is a salamander that retains its larval features for its entire life. Instead of metamorphosing into a land-dwelling adult, it stays aquatic, keeps its external gills, and continues to grow while looking like a permanent juvenile.
Wild axolotls are found only in a small area near Mexico City, primarily in the remaining canals of Lake Xochimilco. They are critically endangered in the wild due to habitat loss, pollution, and introduced fish. Captive populations are common in laboratories and as pets, but the wild population is tiny.
Appearance and unique traits
Most wild axolotls are dark, but the pink and white forms common in captivity are color morphs. Their external gills look like feathery branches on either side of the head. They can regenerate limbs, parts of the spinal cord, and even portions of the brain—an ability that has made them important research animals.
Adults typically reach 15 to 30 centimeters in length. They breathe through their gills, lungs, and skin, and they prefer cool, oxygen-rich water.
Why they stay young
This condition is called neoteny. Axolotls produce low levels of thyroid hormone, which normally triggers metamorphosis in other salamanders. In captivity they can sometimes be induced to metamorphose with hormone treatments, but the result is often a weaker animal with a shorter lifespan.
Because of their limited wild range and popularity in science and the pet trade, axolotls are one of the best-known amphibians even though most people will never see one outside an aquarium.
