Mudpuppies are large salamanders with red feathery gills that never leave the water. They are native to central North America. They live at the bottom of freshwater streams, ponds, and lakes and need plenty of cover from submerged rocks, logs, and leaf litter.
At the Maryland Zoo in Baltimore, visitors can see mudpuppies in the Cave exhibit of the Maryland Wilderness.
Mudpuppies are solitary animals that come together only during breeding season. They are active year-round, and are most active at night when they forage for food in the sand and leaf-litter of shallow water. They are usually seen walking along the bottom of a pond or stream, although they can also swim in rapid bursts. During the day, they tend to stay hidden under rocks or logs or in submerged weeds.
Mudpuppies are opportunistic feeders that will eat anything they can catch. They rely more on smell than eyesight to locate prey. Crayfish are a staple of their diet, but they also eat plenty of other things, including worms, fish, amphibians, fish and amphibian eggs, aquatic insects, and other aquatic invertebrates.
Despite their large size, mudpuppies are well camouflaged against the gravel and silt on the bottom of any pond or stream. This helps them snatch unsuspecting prey and avoid predation themselves. Mudpuppies are ordinarily brown to gray-brown and splotched in appearance. They have flat heads, short, rudder-like tails, and four toes on each of their four limbs. They are primitive-looking creatures that retain most of their larval traits through adulthood, including gills, a swimming tail fin, and an absence of eyelids. Males and females are generally the same size and are similar in appearance.
Mudpuppies remain active through the winter and have been known to surprise ice fishermen by grabbing bait on their lines! Unfortunately for mudpuppies, fishermen often kill them out of fright and the mistaken belief that they are poisonous.
Mudpuppies mate in the fall but females do not deposit their eggs until the following spring. Females prepare rudimentary nests – usually nothing more than a hollowed-out depression beneath a large, flat rock or log in relatively shallow and quiet water. Females then turn upside down and deposit their eggs singly along the bottom of the overhanging rock or log. The eggs attach to the rock or log. One female will deposit from 30 to 200 eggs.
Females stay in their nests, guarding their eggs until they hatch, which occurs within 1 to 2 months depending on the temperature of the water. The newborn mudpuppies initially stay near each other and their mothers, but how long this behavior lasts is unknown. Hatchlings start out just under an inch long, and are dark brown with light yellow stripes along their sides.
Predictably, mudpuppies are most likely to be eaten when they are small. Many animals feed on mudpuppy eggs and hatchlings, including insects, fish, other salamanders, other mudpuppies, and leeches.
Adult mudpuppies have a few defenses that they employ to avoid predation. They are very well camouflaged, they hide well, and they have sense organs in their skin that detect pressure changes and water movement, which can alert them to nearby predators. Nonetheless, mudpuppies have several predators to beware of, including large fish, large turtles, water snakes, herons, and some mammals.
Mudpuppies are considered common throughout their range but are under more pressure in some places than others. In Maryland, mudpuppies are listed as endangered/extirpated, meaning that they once lived in the state but are not known to now. Mudpuppies are declining in some parts of their range due mainly to habitat loss and degradation caused by development projects, resulting over-siltation of waterways, and water pollution.