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Necturus maculosus

What do they look like?

Mudpuppies are between 20 and 33 cm in length. They are entirely aquatic and have large, maroon colored gills throughout their life. They are gray or rusty brown, to nearly black, marked with black or blue-black spotting or blotching. The pattern ranges from a few random spots to thick stripes. The belly is whitish to grayish, and sometimes has bluish black spots. The head of all mudpuppies is flat, and the tail is short and flattened for swimming. Four toes are found on each of four limbs. Young mudpuppies are black with longitudinal yellow stripes.

  • Sexual Dimorphism
  • sexes alike
  • Range length
    20 to 33 cm
    7.87 to 12.99 in

Where do they live?

Mudpuppies are found from southeast Manitoba to southern Quebec, south to south Missouri and northern Georgia. (Conant and Collins, 1998; Harding, 2000)

What kind of habitat do they need?

Mudpuppies live in rivers, weedy ponds, some large lakes, and in lower parts of streams that do not dry up in the summer. Mudpuppies need water that has an abundance of shelter. They reside under logs, rocks, or weeds during the day. They are rarely seen, but may be found under rocks in shallow water. Mudpuppies can be found in either shallow or deep water, depending on the season. They have been reported in water as deep as 30 meters.

  • Aquatic Biomes
  • lakes and ponds
  • rivers and streams
  • Range depth
    30 (high) m
    98.43 (high) ft

How do they grow?

Mudpuppy eggs take 1 to 2 months to develop, depending on the water temperature. Mudpuppies, like other mudpuppies and waterdogs, stay in their larval form for their entire lives.

How do they reproduce?

Mudpuppy males join females in sheltered areas under rocks or logs in shallow water during the fall. Males swim and crawl around the females and eventually deposit a small plug of sperm on the substrate. Females pick up the sperm plug and store it inside themselves until it is used to fertilize their eggs in the spring.

Courtship and mating are in the fall, but some southern populations breed in winter. In spring, females excavate underwater nests and hang 18 to 180 eggs from the nest ceiling. Nests are made in areas with rocks, logs, or other debris for shelter and in water that is 10 cm to 3 m deep. Once hatched, larvae are 20 to 25 mm in length. It takes 4 to 6 years for a mudpuppy to reach sexual maturity.

  • How often does reproduction occur?
    Mudpuppies breed once a year.
  • Breeding season
    Courtship and breeding occurs in the fall, or during winter in southern populations. Fertilization and development occur in the spring.
  • Range number of offspring
    18 to 180
  • Range time to hatching
    1 to 2 months
  • Range age at sexual or reproductive maturity (female)
    4 to 6 years
  • Range age at sexual or reproductive maturity (male)
    4 to 6 years

Female mudpuppies lay their eggs in nest cavities that they dig in sheltered areas beneath rocks and logs. Nest openings usually face downstream. The eggs are attached to the roof of the nest and the females remains with them until they hatch - between 1 and 2 months. (Harding, 2000)

  • Parental Investment
  • pre-fertilization
    • provisioning
    • protecting
      • female
  • pre-hatching/birth
    • protecting
      • female

How long do they live?

Mudpuppies have been known to live upwards of 20 years. (Petranka, 1998)

  • Average lifespan
    Status: captivity
    20 years

How do they behave?

Mudpuppies are completely aquatic. They are usually nocturnal, although in murky or weedy water, they may be active during the day. Mudpuppies are solitary animals, coming together only to reproduce in the fall. They are active throughout the year, and do not hibernate. Individuals do not appear to migrate in streams, although they travel to deeper water in winter and summer and prefer shallow waters in spring and fall. Mudpuppies usually walk along the bottoms of lakes and rivers, but can also swim with a fish-like movement of their bodies. ("University of Georgia. Mudpuppy or Waterdog, Necturus maculosus", 1999; Conant and Collins, 1998; Harding, 2000)

How do they communicate with each other?

Mudpuppies have sense organs in their skin that help them detect water movement and pressure changes. These sense organs help them avoid predators. They have small eyes that they use to see with and a good sense of smell, which they use to locate some prey.

What do they eat?

Mudpuppies eat a variety of aquatic organisms. They are opportunistic feeders and will eat whatever they can catch. Crayfish are a major part of their diet. They also eat insect larvae, small fish, fish eggs, aquatic worms, snails, and other amphibians are also eaten. They will also eat carrion and are often caught in traps that are baited with dead fish.

  • Primary Diet
  • carnivore
    • eats non-insect arthropods
  • Animal Foods
  • amphibians
  • fish
  • eggs
  • carrion
  • insects
  • terrestrial non-insect arthropods
  • mollusks
  • terrestrial worms
  • aquatic crustaceans

What eats them and how do they avoid being eaten?

Large fish, water snakes, and wading birds, such as herons, prey on mudpuppies. Mudpuppies avoid predators by hiding under logs, rocks, or thick vegetation. ("University of Georgia. Mudpuppy or Waterdog, Necturus maculosus", 1999; Conant and Collins, 1998; Harding, 2000)

What roles do they have in the ecosystem?

Mudpuppies are important predators of aquatic invertebrates and small fish in their native aquatic ecosystems. They also are eaten by larger aquatic predators, like large fish, herons, and water snakes.

Do they cause problems?

Mudpuppies have no negative impact on humans. Some people believe that they eat the eggs of game fish and kill them, but there is no evidence that mudpuppies impact game fish populations. People are also sometimes frightened by the strange appearance of mudpuppies, but they are completely harmless.

How do they interact with us?

Mudpuppies have little economic importance. They are sometimes collected and used in research and education. They are important members of native aquatic ecosystems. (Harding, 2000)

  • Ways that people benefit from these animals:
  • research and education

Are they endangered?

Mudpuppies are locally common throughout their range, although populations are in decline in some areas. They can be found in a variety of aquatic habitats. Habitat destruction from polluted water and loss of ponds and lakes through development is a threat to some populations. Because of their sensitive skin, they are especially vulnerable to toxins in the water. Populations are also threatened by needless persecution, as some anglers kill mudpuppies in the mistaken belief that they threaten populations of game fish. Mudpuppies are listed as endangered in Iowa and special concern in Maryland and North Carolina.


Tanya Dewey (editor), Animal Diversity Web.

Erin Siebert (author), Michigan State University, James Harding (editor), Michigan State University.



living in the Nearctic biogeographic province, the northern part of the New World. This includes Greenland, the Canadian Arctic islands, and all of the North American as far south as the highlands of central Mexico.

World Map

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends.


an animal that mainly eats meat


flesh of dead animals.


uses smells or other chemicals to communicate


animals which must use heat acquired from the environment and behavioral adaptations to regulate body temperature


union of egg and spermatozoan


mainly lives in water that is not salty.


animals that have little or no ability to regulate their body temperature, body temperatures fluctuate with the temperature of their environment, often referred to as 'cold-blooded'.

internal fertilization

fertilization takes place within the female's body


offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).


A large change in the shape or structure of an animal that happens as the animal grows. In insects, "incomplete metamorphosis" is when young animals are similar to adults and change gradually into the adult form, and "complete metamorphosis" is when there is a profound change between larval and adult forms. Butterflies have complete metamorphosis, grasshoppers have incomplete metamorphosis.


Having one mate at a time.


having the capacity to move from one place to another.


specialized for swimming

native range

the area in which the animal is naturally found, the region in which it is endemic.


active during the night


reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.


having more than one female as a mate at one time

seasonal breeding

breeding is confined to a particular season


remains in the same area


reproduction that includes combining the genetic contribution of two individuals, a male and a female


lives alone


uses touch to communicate


that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle).


movements of a hard surface that are produced by animals as signals to others


uses sight to communicate


1999. "University of Georgia. Mudpuppy or Waterdog, Necturus maculosus" (On-line). Accessed November 16, 1999 at

Conant, R., J. Collins. 1998. A Field Guide to Reptiles and Amphibians. NY: Houghton Mifflin Company.

Cook, F. 1984. . Introduction to Canadian Amphibians and Reptiles. Ottawa, Canada: National Museum of Canada.

Harding, J. 2000. Amphibians and Reptiles of the Great Lakes Region. Ann Arbor, Michigan: The University of Michigan Press.

Levell, J. 1997. A Field Guide to Reptiles and the Law. Serpent's Tale Books.

Monds, S. "Representative Species - Canadian Great Lakes Salamanders" (On-line). Accessed November 16, 1999 at

Petranka, J. 1998. Salamanders of the United States and Canada. Washington and London: Smithsonian Institution Press.

University of Michigan Museum of ZoologyNational Science Foundation

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Siebert, E. 2008. "Necturus maculosus" (On-line), Animal Diversity Web. Accessed April 23, 2014 at

BioKIDS is sponsored in part by the Interagency Education Research Initiative. It is a partnership of the University of Michigan School of Education, University of Michigan Museum of Zoology, and the Detroit Public Schools. This material is based upon work supported by the National Science Foundation under Grant DRL-0628151.
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