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Axolotls average 4-7 inches in length, but specimens of up 12 inches have been recorded.
The legs and feet are small and weak, while the tail is long. A fin runs from the back of the head to the tail, and another along the underside of the tail. There are four fingers on each of its front legs and five toes on each of its back legs. The most notable features are the three pairs of feathery gills on each side of the head.
Wild axolotls are usually black, or dark brown with black spots. Laboratory and aquarium axolotls have been bred in a variety of color morphs, ranging from natural to albino.
Distribution and Habitat
Historically, axolotls were found in lakes Chalco and Xochimilco, two of the many lakes which once ringed Mexico City, Mexico. The former lake no longer exists, and the latter has been reduced to little more than a series of canals, pools, and irrigation ditches.
In the wild, axolotls prefer deep brackish water with plenty of vegetation.
Breeding generally occurs from March to June.
The male attracts a female by a courtship dance, secreting a pheromone, and swishing his tail. Mating consists of the male depositing a packet of sperm on the lake bottom which the female then picks up with her cloaca. Up to 600 eggs are laid about a week later. The eggs are surrounded by a protective jelly coat and are laid singly, unlike frog eggs (which are laid in clumped masses), because they possess higher oxygen requirements. They are often attached to substrates such as rocks or floating vegetation.
Larvae hatch in about three weeks. Each is about 1/2 inch long and will remain on the rock or plant where it was laid for its first week. If the water is warm and food is plentiful it will have reached its full length by the winter.
Unlike most amphibians, axolotls rarely metamorphose into land-dwelling salamanders, as sexual maturity is reached in the larval stage. Although the transition into salamander can be induced in the laboratory via thyroid hormone injections, wild axolotls will only complete the transformation if the water in which they live dries up.
Generally the top predator in their natural environment, adult axolotls will eat anything that they can catch, including molluscs, fishes, and arthropods. Prey must be moving, however, and even captive axolotls will ignore food that is simply "laying around."
Axolotls are solitary and may be active at any time of the day.
Axolotls are heavily studied because of their amazing regenerative ability. Instead of forming scar tissue when wounded, the axolotl can regenerate tissue at the wound site and even re-grow missing limbs.
Because its natural habitat is shrinking almost daily, the axolotl is considered critically endangered.
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This page was last updated on September 15, 2018.