|Weight||Females: about 170–180 g (6.0–6.3 oz); males: about 125–130 g (4.4–4.6 oz)|
|Total length||up to 30 cm (12 in)|
|Head Length||40–46 mm (1.6–1.8 in)|
|Tail Length||97–120 mm (2.4–3.0 in)|
Data sources: Gresens (2004); Griffiths, Bride, et al. (2004); Pasmans (2014); SEMARNAT (2018)
Most axolotls retain juvenile traits, like a prominent tail fin and feathery gills, into adulthood.
This life history strategy, known as paedomorphy, benefits salamanders that evolved in permanent bodies of water, like those historically found in Central Mexico. Paedomorphy evolved multiple times among the axolotl's close relatives, the mole salamanders (Family Ambystomatidae).
Under some conditions, axolotls go through metamorphosis — but how commonly this occurs in the wild isn't known.
Image credits: © John P. Clare via Flickr (embryo, hatchling, adult). Some rights reserved.
A wild axolotl's skin typically matches the dark brown color of its muddy lake home. But axolotls bred in managed care can be many colors: white, golden, multicolored, or albino.
The first white mutant axolotl appeared in Paris in the late 1860s.
People sometimes breed axolotls with tiger salamanders, yielding still more varied color and skin patterns.
Image credit: © San Diego Zoo Wildlife Alliance. All rights reserved.