Axolotl
Ambystoma mexicanum
The axolotl, whose name comes from the Nahuatl language, is a very culturally significant animal and seen as a representation of renovation, regeneration, and the cycle of life. Their native range today centers on the canals of Xochimilco Valley near Mexico City, Mexico.
Axolotls are related to tiger salamanders but are neotenic: in other words, they never go through metamorphosis and “grow up” to become adult salamanders. Instead, they keep their juvenile characteristics (like the gills around their heads that they are so famous for). Because of their prominent gills, they remain aquatic throughout their whole life span instead of living on land like most adult salamanders.
Credit: Robin Riggs / Aquarium of the Pacific
SPECIES IN DETAIL
Axolotl
Ambystoma mexicanum
CONSERVATION STATUS: Critically endangered
CLIMATE CHANGE:
At the Aquarium
Pacific Visions Babies Gallery
Geographic Distribution
The canals at Xochimilco, Chalco Lake, and Chapultepec Lake, Mexico
Habitat
For centuries, axolotls lived in the waters that formed Lake Xochimilco as part of a high-altitude lake system. The lake has now been reduced to an area of only 40 square kilometers of artificial canals. This is currently one of the only known habitats for axolotls remaining outside of those under human care.
Within this habitat, axolotls seem to prefer areas where there are plants to help them hide during the day.
Physical Characteristics
Axolotls have an iconic appearance, largely characterized by the feathery external gills that line their flat heads. They have four limbs but unlike other adult salamanders, their long tail has a fin that stretches from their head to the tip. They don’t have moveable eyelids, which accounts for their wide-eyed appearance.
In their natural habitats, most axolotls are spotted and dark-colored (generally black, brown, or gray). This helps them camouflage into their surroundings. The light-colored axolotls, including the well-known pink type, are rare outside of human care and have been bred as pets by humans.
Size
Axolotls range from between 15 to 46 centimeters (6 to 18 inches) in length and can weigh anywhere from 57 to 227 grams (2 to 8 ounces).
Diet
Axolotls are nocturnal creatures, burrowing during the day in mud and within plants to hide from potential predators. At night, they eat worms, mollusks, small fish, insect larvae, and crustaceans using a suction motion.
Reproduction
Male axolotls deposit a packet of sperm onto a hard surface, which the female then picks up to fertilize internally. Pheromones and other chemical cues play a role. Courtships can have elaborate displays with chasing, circling, and nudging behaviors.
Behavior
They are known to have individual personalities, displaying both social and solitary patterns of interacting, as well as more dormant and active tendencies. Invasive species like tilapia can influence their hunting behavior, making them less efficient.
Adaptation
Axolotls can regenerate their limbs, tails, heart tissue, eyes, and even parts of their central nervous system.
When they are injured, a blastema (a mass of cells) forms in the area. This can regenerate an entire complex structure, like a limb.
While many amphibians share these regenerative abilities, the axolotl retains the ability to regenerate complex body parts throughout adulthood.
Axolotls don’t develop scar tissue in response to wounds, like mammals do. This is of interest to scientists for potential application to human healthcare.
Longevity
Axolotl can live between 10 and 15 years under human care.
Conservation
Factors like urbanization, human-driven habitat destruction, pollution, and the introduction of invasive species like tilapia have been displacing the native axolotl population in Xochimilco. The decline has rapidly increased: In 1998, there were as many as 6,000 axolotls per square kilometer; by contrast, in 2014, there were between 50 and 1,000 left outside of those under human care.
Axolotls are extremely sensitive to water quality and conditions, making them quite vulnerable to pollution and impacts of climate change. Local Mexican farms, businesses, and conservationists are making successful efforts to protect axolotls in their natural habitats, including efforts to improve water quality and reduce pollution levels in the lake.
Axolotls are still highly sought-after for their use in biomedical research and are generally bred for that purpose.
Special Notes
Even though these limb-regenerating creatures breathe through the feathery gills on their heads, axolotls do develop functional lungs.
SPECIES IN DETAIL | Print full entry
Axolotl
Ambystoma mexicanum
CONSERVATION STATUS: Critically endangered
CLIMATE CHANGE:
Pacific Visions Babies Gallery
The canals at Xochimilco, Chalco Lake, and Chapultepec Lake, Mexico
For centuries, axolotls lived in the waters that formed Lake Xochimilco as part of a high-altitude lake system. The lake has now been reduced to an area of only 40 square kilometers of artificial canals. This is currently one of the only known habitats for axolotls remaining outside of those under human care.
Within this habitat, axolotls seem to prefer areas where there are plants to help them hide during the day.
Axolotls have an iconic appearance, largely characterized by the feathery external gills that line their flat heads. They have four limbs but unlike other adult salamanders, their long tail has a fin that stretches from their head to the tip. They don’t have moveable eyelids, which accounts for their wide-eyed appearance.
In their natural habitats, most axolotls are spotted and dark-colored (generally black, brown, or gray). This helps them camouflage into their surroundings. The light-colored axolotls, including the well-known pink type, are rare outside of human care and have been bred as pets by humans.
Axolotls range from between 15 to 46 centimeters (6 to 18 inches) in length and can weigh anywhere from 57 to 227 grams (2 to 8 ounces).
Axolotls are nocturnal creatures, burrowing during the day in mud and within plants to hide from potential predators. At night, they eat worms, mollusks, small fish, insect larvae, and crustaceans using a suction motion.
Male axolotls deposit a packet of sperm onto a hard surface, which the female then picks up to fertilize internally. Pheromones and other chemical cues play a role. Courtships can have elaborate displays with chasing, circling, and nudging behaviors.
They are known to have individual personalities, displaying both social and solitary patterns of interacting, as well as more dormant and active tendencies. Invasive species like tilapia can influence their hunting behavior, making them less efficient.
Axolotls can regenerate their limbs, tails, heart tissue, eyes, and even parts of their central nervous system.
When they are injured, a blastema (a mass of cells) forms in the area. This can regenerate an entire complex structure, like a limb.
While many amphibians share these regenerative abilities, the axolotl retains the ability to regenerate complex body parts throughout adulthood.
Axolotls don’t develop scar tissue in response to wounds, like mammals do. This is of interest to scientists for potential application to human healthcare.
Axolotl can live between 10 and 15 years under human care.
Factors like urbanization, human-driven habitat destruction, pollution, and the introduction of invasive species like tilapia have been displacing the native axolotl population in Xochimilco. The decline has rapidly increased: In 1998, there were as many as 6,000 axolotls per square kilometer; by contrast, in 2014, there were between 50 and 1,000 left outside of those under human care.
Axolotls are extremely sensitive to water quality and conditions, making them quite vulnerable to pollution and impacts of climate change. Local Mexican farms, businesses, and conservationists are making successful efforts to protect axolotls in their natural habitats, including efforts to improve water quality and reduce pollution levels in the lake.
Axolotls are still highly sought-after for their use in biomedical research and are generally bred for that purpose.
Even though these limb-regenerating creatures breathe through the feathery gills on their heads, axolotls do develop functional lungs.