Necturus maculosusMudpuppy

Geographic Range

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


Mudpuppies live in rivers, weedy ponds, some large lakes, and in perennial streams. 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. (Conant and Collins, 1998; Cook, 1984; Harding, 2000)

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

Physical Description

Mudpuppies are between 20 and 33 cm in length. They are neotenic (permanent larvae) and retain large, maroon colored external gills throughout their life. Mudpuppies that live in cold water with high oxygen concentrations have shorter gills than those living in oxygen depleted waters. They have a general coloration of gray or rusty brown, to nearly black. They are marked with black or blue-black spotting or blotching. The spotting pattern ranges from a few spots, to many spots, or spots merging to form stripes. The belly is whitish to grayish, and sometimes has bluish black spots. There are two generally recognized subspecies. Necturus m. maculosus individuals have rusty brown to gray dorsa with conspicuous spotting. The underside is gray, and may or may not be spotted. Louisiana waterdogs (N. m. louisianensis) have light yellowish brown to tan dorsa. The dorsal side is marked with large spots and sometimes a dorsal stripe. The belly is light colored with no spots.

The head of all mudpuppies is flat and the tail is short and laterally compressed for swimming. Four toes are present on each of four well-developed limbs. Males and females look very similar. However, male cloacae have two prominent papillae directed backward. In the breeding season, males have swollen cloacae. Female cloacae are slit-like and usually surrounded by light coloration. Young mudpuppies are black with longitudinal yellow stripes. (Conant and Collins, 1998; Cook, 1984; Harding, 2000; Petranka, 1998)

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


Mudpuppy eggs take 1 to 2 months to develop, depending on water temperature. Mudpuppies, like other members of Proteidae, are neotenic, retaining their larval form throughout life. (Harding, 2000)


Mudpuppies form mating aggregations in the fall in shallow water. Males join females in sheltered areas under rocks or logs in shallow water. Males swim and crawl around the females and eventually deposit a 1 cm spermatophore. Females pick up the spermatophores in their cloaca, where it is stored until spring. (Harding, 2000)

Courtship and mating take place in the fall, but some southern populations breed primarily in winter. Fertilization is internal, with the female taking up the male's spermatophore in her cloaca and storing it there until fertilization in the spring. In spring, females excavate nest cavities and suspend from 18 to 180 eggs from the nest cavity ceiling. Nest cavities are constructed in areas with rocks, logs, or other debris for shelter and in water that is 10 cm to 3 m in depth. Eggs are between 5 and 11 mm in diameter. Once hatched, larvae are 20 to 25 mm in length. It takes 4 to 6 years for a mudpuppy to reach sexual maturity, at a body length of about 20 cm. ("University of Georgia. Mudpuppy or Waterdog, Necturus maculosus", 1999; Cook, 1984; Harding, 2000; Petranka, 1998)

  • Breeding interval
    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


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

  • Average lifespan
    Status: captivity
    20 years


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)

Communication and Perception

Mudpuppies have sense organs in their skin that help them detect water movement and pressure changes. These sense organs help them avoid predators. They also have a good sense of smell, which they use to locate some prey. They have small eyes that they use to perceive light. Courtship is the only time when mudpuppies communicate with each other to coordinate mating. They may use a combination of touch and chemical cues in courtship. (Harding, 2000)

Food Habits

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. (Cook, 1984; Harding, 2000)

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


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)

Ecosystem Roles

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.

Economic Importance for Humans: Positive

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)

  • Positive Impacts
  • research and education

Economic Importance for Humans: Negative

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.

Conservation Status

Mudpuppies are locally common throughout their range, although populations are in decline in some areas. They are tolerant of a variety of aquatic habitats. Habitat destruction from siltation and pollution, and habitat loss due to 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 impact populations of game fish. Mudpuppies are listed as endangered in Iowa and special concern in Maryland and North Carolina. (Levell, 1997; Petranka, 1998)


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. Synapomorphy of the Bilateria.


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.


having a body temperature that fluctuates with that of the immediate environment; having no mechanism or a poorly developed mechanism for regulating internal body temperature.

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


mature spermatozoa are stored by females following copulation. Male sperm storage also occurs, as sperm are retained in the male epididymes (in mammals) for a period that can, in some cases, extend over several weeks or more, but here we use the term to refer only to sperm storage by females.


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.