Mudpuppies do not hibernate. They do however reproduce in a rather unusual way. These creatures mate in the fall and the female then waits until spring to lay her eggs. The male then joins the female mudpuppy in a sheltered area, perhaps under a rock or lock located in shallow water. The male mudpuppy then begins the courtship taking part in a type of swimming ceremony.
As he swims and crawls around the female mudpuppy, he deposits a mass of jelly like sperm which the female then moves over top of and takes them into her cloaca. In April or May she will then deposit anywhere from 50 to 100 eggs within a nest that she digs out under rocks or sticks in the water.
After she lays these eggs it usually takes anywhere from 30 to 50 days for them to hatch. During this time the female mudpuppy stays with her nest until they eggs hatch, but will then swim away once the babies emerge during their larval stage.
The larva mudpuppies will begin to grow legs when they are about a month old. It will be a light color with dark gray stripes and unlike most amphibians does not go through the metamorphosis during this larval stage that allows them to exist outside of the water. It is for this reason that the mudpuppy is confined to be a completely aquatic creature during all stages of its life. The mudpuppy also retains its three sets of gills into adulthood.
These creatures take up to two years or so to reach their full adult size and it is then that they lose their stripes. It reaches sexual maturity within 5 years and can then live for an additional 25 years or so. The adult mudpuppy lives under rocks and logs within the water and has been seen at depths up to 70 feet. These creatures on average will reach a length anywhere from 8 to 13 inches, one of the largest mudpuppies ever discovered was a whopping 19 inches.