FaunaHub

Mudpuppy (Necturus maculosus)

AmphibianSalamanderNorth America

Mudpuppy (Necturus maculosus), an aquatic salamander with feathery red external gills.

Common mudpuppy (Necturus maculosus).

Image: Peter Paplanus from St. Louis, Missouri, CC BY 2.0, via Wikimedia Commons.

Overview

The mudpuppy (Necturus maculosus) is a large, fully aquatic salamander of eastern North America, easily recognised by the bushy, blood-red external gills that fan out on either side of its head. Unlike most salamanders, the mudpuppy never fully transforms: it keeps these larval gills and its aquatic lifestyle throughout life (a condition called neoteny), breathing the dissolved oxygen in water rather than living on land.

Mudpuppies have a stout, flattened body, four short legs, a paddle-like tail, and mottled brownish skin. Despite local myths, they are completely harmless to people and are not venomous or poisonous.

Note: several related Necturus species exist; details here use the common mudpuppy as a reference. Treat general statements as approximate and verify against authoritative sources.

Habitat & Range

Mudpuppies live in lakes, rivers, streams, and ponds across much of the northeastern and central United States and parts of Canada. They stay in the water year-round — even active under ice in winter — sheltering under rocks, logs, and debris on the bottom, and they do best in clean, well-oxygenated water.

Diet

Mudpuppies are carnivores that hunt along the bottom for crayfish, aquatic insects, worms, snails, small fish, and fish eggs. They are mostly nocturnal foragers, using smell and touch to find prey in murky water, and they seize it with a quick gulp.

Behavior

The size and colour of a mudpuppy's external gills change with conditions: in warm, low-oxygen, or stagnant water the gills grow larger and redder to absorb more oxygen, while in cold, fast, oxygen-rich water they are smaller. Mudpuppies are mostly nocturnal and secretive, hiding by day and foraging at night. They can be long-lived for an amphibian, and males guard nest sites where females attach eggs to the underside of rocks.

Human Interaction & Conservation

Mudpuppies are harmless and are sometimes caught accidentally by anglers, who may wrongly believe them to be venomous or harmful to fish — neither is true, and they should simply be released unharmed. Like other amphibians they are sensitive to pollution, so their presence is a sign of a healthy waterway, and declines can signal water-quality problems. Consult AmphibiaWeb and the IUCN Red List for current status.

More photos of the mudpuppy

A mudpuppy underwater, showing its bushy gills and stout legs.

Mudpuppy (Necturus maculosus).

Image: Brian Gratwicke, CC BY 4.0, via Wikimedia Commons.

Frequently Asked Questions — Mudpuppy

Why does a mudpuppy have those red feathery gills?
The bushy red structures are external gills, which the mudpuppy keeps for its whole life. Because it stays aquatic and never fully transforms (a state called neoteny), it uses these gills to absorb oxygen directly from the water. The gills get larger and redder in warm or low-oxygen water and smaller in cold, oxygen-rich water.
Are mudpuppies dangerous or poisonous?
No. Despite folk myths, mudpuppies are completely harmless to people — they are not venomous, not poisonous, and their bite is no real threat. Anglers who catch one accidentally sometimes fear it harms fish stocks, but that's also a myth; the best thing is simply to release it unharmed.
What do mudpuppies eat?
Mudpuppies are carnivores that forage along the bottom mainly at night, eating crayfish, aquatic insects, worms, snails, small fish, and fish eggs. They locate prey by smell and touch in murky water and grab it with a quick gulp.
Are mudpuppies the same as axolotls?
They're both neotenic, fully aquatic salamanders that keep their gills for life, but they are different animals. Axolotls are mole salamanders (genus Ambystoma) from Mexico, while mudpuppies (genus Necturus) are a separate North American group. They share the gilled, water-dwelling lifestyle through convergent biology rather than close kinship.

Sources and further reading

Authoritative wildlife references used for general educational context. Conservation status should always be verified against current IUCN Red List data. External links open in a new tab.