Species Fact Profile: Axolotl (Ambystoma mexicanum)

Axolotl

Ambystoma mexicanum (Shaw, 1789)

Range: Central Mexico
Habitat: Lake Xochimilco
Diet: Algae, Aquatic Invertebrates
Social Grouping: Solitary
Reproduction:  Breed from March through June in the wild.  Sexually mature at 12-18 months.  Males dance to initiate courtship, deposit sperm packets for females to pick up.  Hundreds of eggs laid in mucous envelopes, glued to rocks and other substrate.  Hatch after 2-3 week incubation period.
Lifespan: 10-15 Years
Conservation Status: IUCN Critically Endangered, CITES Appendix II

• Body length 30 centimeters.  Weight 125-180 grams.  Females larger than males
• Demonstrate an extreme form of neoteny, in which salamanders do not fully undergo metamorphosis and retain their larval features, most notably their branch-like gills
• If the habitat dries up, the normally larval-like axolotl is capable of undergoing metamorphosis and turning into a "normal" salamander.  Metamorphosis can be induced in captives by thyroid hormone injections
• Coloration is dark brown or green, often blotchy.  Albinos are frequently bred and seen in captivity, but are not seen in the wild.
• If wounded, they are capable of converting the affected cells into a stem-cell like state and regrow missing tissue, including whole limbs
• Herons and other marsh birds are the primary natural predator; larger fishes have recently been introduced to the lakes where axolotls live, adding to the predation pressure.  They are aso consumed by local peoples
• Common name means "water dog" in the Aztec language, referring to the Aztec god Xolotl, god of the dead and resurrected, as well as ugly beings 
• Commonly used in biomedical research due to their unique properties.  Breeds very well in captivity; before breeding was established, capture of wild axolotls was a major form of population decline.
• Major threat causing the decline of the species is habitat loss (one of the two lakes where tis species occurred no longer exists) and pollution from agriculture and sewage disposal, as well as the introduction of predatory fishes