Home: Animals: Amphibians: Axolotl

Bio Facts
Common Name: Axolotl Axolotl
Scientific Name: Ambystoma mexicanum
Family: Ambystomidae
Order: Caudata
Class: Amphibia
Range: Lake Zochimilco near Mexico City, Mexico
Habitat:

Lakes and ponds
Description: The axolotl is a neotenic salamander, one that retains its larval form with gills, and usually living in the water all of its life. They are black or dark brown in color with black spots.  Albino and leucistic forms are rare but do occur naturally.  They are about 4 to 7 inches in length, with reports of some reaching 10-12 inches in the wild.  The axolotl has two pairs of legs, front and back.  The legs and feet of the axolotl are small and weak.  A dorsal fin runs from the back of the head to the tail.  A ventral fin is evident under the tail.  The tail is strong and can propel the axolotl through the water at rather rapid speeds.  Three feathery gills are located on either side of the body just behind the head and immediately in front of the forelimbs. Maybe one out of one thousand adults will transform into the terrestrial form, loosing the gills and living on land.
Life Expectancy: 10 to 15 years (oldest one recorded at 25 years in a French laboratory)
Sexual Maturity: The axolotl usually becomes sexually mature while still in a larval state.  It only rarely goes through the final stage of metamorphosis.
Diet: In the wild, axolotls eat worms, mollusks and other invertebrates.  In the Zoo, they are fed salmon pellets and freshly hatched brine shrimp.
Status: IUCN – Vulnerable; CITES – Appendix II
Behaviors:

Axolotls are neotonous, meaning they can live and breed in what is really a larval form, more or less an immature state.

In the wild, axolotls spend most of their time at the bottom of the pond.  Occasionally, they swim around only to sink to the bottom again.

Adult and juvenile axolotls cannot be kept together with complete safety, as they are liable to bite off each other’s gills and feet, and bite pieces out of the tail.

Males attract females with a courtship dance and chemical secretions from glands in the abdomen.  Swishing the tail may just help spread the chemical attractants that entice females to swim toward males. 

Salamanders and newts have a system of internal fertilization that differs from the usual method.  Normally, a male introduces sperm into the female’s body to meet the eggs waiting there.  In axolotls, a male sheds sperm in a packet called a spermatophore.  It sinks to the bottom of the pond where a female settles over it and picks it up with her cloaca. 

About a week later, 200-600 eggs are laid, in April or May.  They are sticky, and the female attaches them to plants with her back legs.  Young axolotls hatch about 3 weeks later, depending on the temperature of the water.  At this stage, they are only about ½ inch long and remain on the plant where the eggs are laid.  After a week they start swimming in search of food.  If the water is warm and food plentiful, they will grow to be 5 to 7 inches long by winter.  During the coldest part of the year, they hibernate, not eating until the water temperatures warm up again in the spring.
Adaptations:

Axolotls are capable of regenerating lost body parts.  These amphibians are often used in scientific and medical facilities for studies involving regeneration.

Unlike most salamanders, axolotls do not leave the water.  Breathing takes place through the skin and the feathery gill structures.  Axolotls kept in well-aerated tanks may lose their feathery gills since the air needed for survival can be obtained directly through the skin of the animal.  Some experiments have been conducted in laboratories where the amount of water has been decreased, and axolotls have lost the external gills and developed primitive lungs.  This transformation also tended to shorten the lifespan of the animals.
Special Interest: The axolotl is a salamander unique to a single lake and series of canals in Mexico City, where they are regarded as a delicacy when roasted.  They are also reputed to have healing powers.
Folklore:

It’s name means “water dog” in the ancient Aztec language.  It is derived from the name of the Aztec god, Xolotl.

The name axolotl is Mexican for “water sport.”

Conservation: The Mexican Government has recognized this interesting salamander and has established a conservation program based on breeding and "head starting" juveniles in captivity and then releasing them.
Jacksonville Zoo History: Axolotls first arrived at the Jacksonville Zoological Gardens in October 1996.