Axolotl (Ambystoma mexicanum) — species profile (taxonomy, geographic range, habitat, physical description, behavior, wild diet, reproduction, lifespan)
Authoritative first-hand species account (Animal Diversity Web, University of Michigan). All bullet facts are verbatim from the cited source and C1-substring verified.
Geographic Range
- Ambystoma mexicanum is historically found in Lakes Chalco and Xochimilco of the Valley of Mexico near Mexico City, Mexico.
Habitat
- The native habitats of A.
- mexicanum are large, relatively permanent (until recently), high-altitude lakes located near Mexico City.
- Of the two lakes - Chalco and Xochimilco - where these animals are historically native, only Xochimilco (elevation: ~ 2,274 m) remains.
- Axolotls are almost extinct in their native habitat, largely due to the introduction of predatory fishes and habitat loss.
Physical Description
- Axolotls are paedomorphic or neotenic aquatic salamanders, meaning they retain certain larval characteristics in the adult, reproductive state.
- They possess feathery external gills and finned tails for swimming.
- Laboratory animals exist in several color morphs, ranging from wild type (dark, mottled brownish-green) to albino.
- Axolotls reach lengths on average of 20 cm (9 inches), but can grow to more than 30 cm (12 inches) in length.
Behavior
- Axolotls are solitary and may be active at any time of the day.
- Key Behaviors natatorial natatorial diurnal diurnal nocturnal nocturnal motile motile sedentary sedentary solitary solitary Communication and Perception Axolotls communicate mainly via visual cues and chemical cues during mating.
- At other times of the year there is little to no intraspecific communication.
- Axolotls can detect electrical fields and also use their vision and chemical cues to perceive their environment and discover prey.
Food Habits (Wild Diet)
- Generally the top predator in their natural environment, axolotls will eat anything that they can catch, including molluscs, fishes, and arthropods, as well as conspecifics.
- Primary Diet carnivore carnivore piscivore piscivore insectivore insectivore eats non-insect arthropods molluscivore molluscivore Animal Foods amphibians fish insects mollusks terrestrial worms zooplankton zooplankton
Reproduction
- The courtship behavior of A.
- mexicanum follows the general Ambystoma pattern; it first involes each animal nudging the other's cloacal region, eventually leading to a "waltz," with both animals moving in a circle.
- Next, the male moves away while undulating the posterior part of his body and tail (resembling a "hula dance"), and the female follows.
- The male will deposit a spermatophore (a cone-shaped jelly mass with a sperm cap) by vigorously shaking his tail for about half a minute, and will then move forward one body length.
Development
- mexicanum is paedomorphic, which means that it retains larval characteristics in the reproductively mature adult form.
- Juvenile and adult axolotls possess feathery, external gills and tail fins suited to an aquatic lifestyle.
- Metamorphosis can be induced in axolotls via thyroid hormone injections.
Ecosystem Roles
- Axolotls were the top predator in their native environment, making them important in structuring community dynamics.
Predation
- Axolotls may be preyed on by large fish and conspecifics.
- Large fish have only recently been introduced into the lakes where axolotls are found, contributing to the demise of their populations.
Conservation Status
- The natural habitat of A.
- mexicanum is nearly gone.
- Historically, they have been known to live in high altitude lakes near Mexico City.
Lifespan
- Expected laboratory longevity is 5 to 6 years; however, some animals have been known to live as long as 10 to 15 years.