Head to head
Axolotl vs Mudpuppy
Both animals look like the same idea: a salamander that never grows up, keeping its frilly external gills, its tail fin, and its aquatic life into adulthood. But the axolotl and the mudpuppy arrived there by different routes and live very different lives. One is a nearly extinct native of one lake system that has become the most studied salamander on Earth; the other is a common, wild predator of North American rivers and lakes.
| Axolotl | Mudpuppy | |
|---|---|---|
| Family | Mole salamanders (Ambystomatidae) | Mudpuppies and waterdogs (Proteidae) |
| Native range | Lake Xochimilco and remaining canals of Mexico City | Rivers and lakes of eastern and central North America |
| Adult size | About 23 to 30 cm | About 30 to 40 cm |
| Why it keeps its gills | Metamorphosis normally never triggers, but can be forced with hormone | The species cannot metamorphose at all |
| Hind foot | Five toes | Four toes |
| Claim to fame | Regrows limbs, organs, and parts of the brain; a major research animal | One of the few salamanders that stays fully aquatic across a huge range |
| Diet | Worms, insect larvae, small fish, crustaceans | Crayfish, worms, snails, fish, fish eggs |
| Conservation status | Critically Endangered in the wild | Least Concern |
Axolotl vs Mudpuppy: common questions
Are axolotls and mudpuppies the same thing?
No, though they are easy to confuse because both are salamanders that keep bushy external gills and live permanently in water. They belong to different families that are not especially close relatives. The axolotl is a Mexican mole salamander, in the same genus as the tiger salamander, and it is the odd one out in a group whose members normally transform into land animals. The mudpuppy belongs to a small family, the Proteidae, whose species are aquatic and gilled for life as a rule, with no land stage in the life cycle. They also come from opposite parts of North America, the axolotl from one high-altitude lake basin in central Mexico and the mudpuppy from the cooler rivers and lakes of the United States and Canada.
Which one can regrow body parts?
Both can regenerate to some degree, as many salamanders can, but the axolotl is in a class of its own and that is why it fills research labs worldwide. An axolotl can regrow a lost leg complete with bones, muscles, nerves, and skin, patched in without scarring, and can also rebuild damaged heart tissue, sections of spinal cord, and parts of the brain, and even accept transplanted limbs. The mudpuppy can regrow a lost tail or limb far more slowly and less completely, and it has not been developed as a laboratory model. Interestingly, an axolotl that is forced to metamorphose into a land salamander loses much of its regenerative ability, which is one reason scientists study the larval form.
Can you keep either as a pet?
Axolotls are widely kept as aquarium pets and are bred in captivity in large numbers, in wild-type, leucistic, albino, and other colours. They need cool, clean, still water, a bare or fine-sand bottom, and no tankmates that might bite their gills, and they can live 10 to 15 years. Because every pet axolotl is captive-bred, keeping one does not harm the wild population, though it also does little to help it. Mudpuppies are occasionally kept by experienced keepers but are much less suitable: they are usually wild-caught, need a large chilled tank with strong filtration, are shy and nocturnal, and in some regions are protected. For most people the axolotl is the practical choice and the mudpuppy is best left in its river.