Are Mudpuppies and Axolotls the Same?

Mudpuppies and axolotls look strikingly similar at first glance. Both are aquatic salamanders with external gills that live their entire lives in water. It is easy to see why people confuse them or wonder if they are the same animal. But despite their similar appearance, mudpuppies and axolotls are actually different species with distinct characteristics. Here is how to tell them apart.

The Key Differences

While both animals share the trait of being permanently aquatic with external gills, they belong to different genera and have some notable differences in size, appearance, habitat, and care requirements.

Axolotls (Ambystoma mexicanum) are native to a single location: Lake Xochimilco in Mexico City, Mexico. They are critically endangered in the wild, with most axolotls today being captive bred for the pet trade and scientific research. Mudpuppies (Necturus maculosus) are native to eastern North America and can be found in rivers, lakes, and streams from southern Canada down through the eastern United States.

Size and Appearance

Mudpuppies are generally larger than axolotls. Adult mudpuppies typically reach 8 to 13 inches in length, with some growing up to 17 inches. Axolotls usually reach 9 to 12 inches. The size difference is not dramatic, but mudpuppies tend to have a more robust, elongated body shape.

One of the easiest visual differences is coloring. Wild mudpuppies are typically brown or rusty brown with dark spots and a lighter belly. Axolotls come in a wide range of morphs including wild type (dark brown/olive), leucistic (pale pink/white), albino, melanoid, golden, and many more thanks to extensive captive breeding programs.

The gills are another distinguishing feature. Both species have feathery external gills, but mudpuppy gills tend to be darker and bushier, while axolotl gills are often more defined and can range from bright red to pale pink depending on the morph and health of the animal.

Why Both Stay Aquatic

Both mudpuppies and axolotls exhibit neoteny, which means they retain juvenile features into adulthood and never undergo full metamorphosis like most salamanders do. While most salamanders lose their gills, develop lungs, and transition to a land dwelling lifestyle as they mature, mudpuppies and axolotls keep their gills and stay in the water permanently.

However, there is an interesting difference. Axolotls are neotenous by default but can be artificially induced to metamorphose through exposure to thyroid hormones (this is not recommended and usually shortens their lifespan significantly). Mudpuppies, on the other hand, are obligate neotenes, meaning they cannot undergo metamorphosis at all, even with hormone treatment. They are permanently aquatic no matter what.

Can You Keep a Mudpuppy as a Pet?

Mudpuppies can be kept as pets, but they are much less common in the pet trade than axolotls. They require similar tank setups with cool, clean water and appropriate filtration. However, mudpuppies have slightly different temperature requirements and tend to prefer cooler water than axolotls, often doing best in water between 55 and 65 degrees Fahrenheit.

Mudpuppies can also be more challenging to feed in captivity. While axolotls readily accept earthworms, pellets, and other captive foods, mudpuppies can be pickier and may require more live food options. Their availability in the pet trade is also limited compared to the wide variety of axolotl morphs available from breeders.

Before getting a mudpuppy, check your local laws. Some states regulate the collection and keeping of native amphibians, and mudpuppies may require permits or be illegal to keep in certain areas.

Can Mudpuppies and Axolotls Live Together?

This is not recommended. They are different species with slightly different care requirements, and housing them together creates risks of stress, aggression, and disease transmission. Each species should be kept in its own appropriately set up tank.

Both mudpuppies and axolotls are fascinating animals that represent unique branches of the salamander family tree. While they share the remarkable trait of permanent aquatic life with external gills, they are distinct species with their own characteristics, native habitats, and care needs. If you love one, you will probably find the other equally interesting.