Mudpuppy Metamorphosis Stages

Mudpuppies, also known as "water dogs," are salamanders that spend their entire lives in water. They can be found at the bottom of lake and river bottoms in the American Midwest and Eastern states. They get their names from a distinctive yelp sound that is said to sound somewhat like a dog's bark. Like other amphibians, mudpuppies experience several transformations duing their lifespans, but they never lose their gills.

  1. Eggs

    • Male and female mudpuppies gather in shallow rocky areas to reproduce. The female salamanders carry fertilized eggs within their bodies throughout the winter. During the spring, the females scratch out nests in the muddy areas surrounded by protective debris, such as rocks and logs, and lay anywhere from a few dozen to few hundred eggs. Mudpuppy eggs measure between 5 and 11 mm in diameter and take one to two months to hatch.

    Larval Stage

    • Larval mudpuppies have three sets of feathery gills at the backs of their heads that allow them to breathe beneath water. The larval stage can last from a few weeks to few years, depending on the species. Larval salamanders also have a fin near their tails to help with swimming. Larval mudpuppies have distinctive white stripes that run down the length of their bodies.

    Adult Stage

    • Most salamanders and newts lose their feathery gills and tail fins when they move on from the larval stage, but mudpuppies retain their juvenile features as they reach sexual maturity. An adult mudpuppy's colors, however, differ from the larval stage. Adult mudpuppies lose the stripes they had as juveniles and can be identified by their solid brown bodies with bluish-black spots. Adult mudpuppies can reach lengths of up to 15 inches.

    Neoteny

    • Unlike other salamanders, mudpuppies exhibit 'neoteny,' a phenomenon in which sexually mature animals retain juvenile characteristics. They never lose the gills they had as juveniles, since they live their entire lives in water. Gills are more efficient than lungs at exchanging gases in water, according to the biology department at the University of Massachusetts Amherst.