Olms and Mudpuppies: Proteidae

Physical characteristics: Mudpuppies reach a length of 8 to 19 inches (20 to 48 centimeters) from tip of snout to tip of tail. They have small eyes, a short tail, small legs, and a squared-off snout. Mudpuppies have camouflage coloring against the dark bottom of lakes, rivers, and streams. The colors vary from deep rusty brown to gray or even black with scattered black or bluish black spots and blotches. The spots sometimes form two rows along the back. A dark bar extends through the eye to the gills. The belly is paler than the back and may or may not have dark spots. The edges of the tail often are tinged with reddish orange. The colors of mudpuppy larvae can be strikingly different from that of adults.

Mudpuppies have different shapes of gills, depending on their environment. Mudpuppies that live in the fast-moving waters of rivers Mudpuppies have different shapes of gills, depending on their environment. Mudpuppies that live in the fast-moving waters of rivers and streams have small gills that stay close to the sides of the animal's head. In warm or slow-moving rivers and lakes, the gills are big and bushy. (Photograph by Jack Dermid. Bruce Coleman Inc.) and streams have small gills that stay close to the sides of the animal's head. In warm or slow-moving rivers and lakes, the gills are big and bushy.

Geographic range: Mudpuppies live in North America in a range that covers essentially the entire Mississippi River drainage system. The range extends from southern Manitoba and Quebec, Canada, in the north to Georgia, Alabama, Mississippi, and Louisiana, United States, in the south.

Habitat: Mudpuppies live in a variety of water habitats, including rivers, streams, canals, and lakes.

Diet: Mudpuppies eat water-dwelling invertebrates and vertebrates, including crayfish and other crustaceans, mollusks, worms, insect larvae, fish, and other amphibians.

Behavior and reproduction: Mudpuppies are active all year and have been seen moving around beneath the ice in mid-winter. Adults are mostly active at night, when they look for food. Mudpuppies hide under rocks and other objects or in burrows during the day. The mating season for mudpuppies is in the autumn or winter, possibly extending into spring, depending on where they live. The fertilized eggs are laid in May or June and attach to the bottoms of large rocks. The female takes care of the eggs and defends them against predators. Hatching takes place in one or two months, depending on the temperature of the water. The newly hatched larvae are approximately 1 inch (2.5 centimeters) long and have two yellow stripes on a dark background. Mudpuppies grow into adults without going through metamorphosis.

Mudpuppies and people: Mudpuppies are collected in large numbers by biological supply companies for use in classrooms and laboratories around the world. They also are caught and sold as pets.

Conservation status: Mudpuppies are not considered threatened or endangered. ∎