Animal Diversity Web

Ge­o­graphic Range

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

• Biogeographic Regions
• nearctic
  • native

Habi­tat

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)

• Habitat Regions
• temperate
• freshwater

• 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)

• Other Physical Features
• ectothermic
• heterothermic
• bilateral symmetry

• Sexual Dimorphism
• sexes alike

• Range length

  20 to 33 cm

  7.87 to 12.99 in

De­vel­op­ment

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)

• Development - Life Cycle
• neotenic/paedomorphic
• metamorphosis

Re­pro­duc­tion

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)

• Mating System
• monogamous
• polygynous

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)

• Key Reproductive Features
• iteroparous
• seasonal breeding
• gonochoric/gonochoristic/dioecious (sexes separate)
• sexual
• fertilization
  • internal
• oviparous
• sperm-storing

• 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

Lifes­pan/Longevity

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

• Average lifespan
  Status: captivity

  20 years

  AnAge

Be­hav­ior

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)

• Key Behaviors
• natatorial
• nocturnal
• motile
• sedentary
• solitary

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)

• Perception Channels
• visual
• tactile
• vibrations
• chemical

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

Pre­da­tion

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)

• Known Predators

  • water snakes (Nerodia)
  • large, predatory fish (Actinopterygii)
  • herons (Ardeidae)

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)

• IUCN Red List

  Least Concern
  More information

• IUCN Red List

  Least Concern
  More information

• US Federal List

  No special status

• CITES

  No special status

• State of Michigan List

  No special status

Con­trib­u­tors

Tanya Dewey (ed­i­tor), An­i­mal Di­ver­sity Web.

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

Ref­er­ences

1999. "Uni­ver­sity of Geor­gia. Mud­puppy or Wa­ter­dog, Nec­turus mac­u­lo­sus" (On-line). Ac­cessed No­vem­ber 16, 1999 at http://​museum.​nhm.​uga.​edu/​~GAW­ildlife/Am­phib­ians/cau­data/Pro­tei­dae/nmaculosus.​html.

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 http://​www.​cciw.​ca/​glimr/​data/​habitat-rehabilitation/​hab42a.​html.

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