Aplodontiidae (Sub-family of Rodentia)

Aplodontiidae, from Greek ἁπλόος (haplóos, “single, simple”) and Greek ὀδούς (odoús, “tooth”), means “simple tooth”, in reference to the fact that all the members of this family have a single large basin comprising the bulk of each cheek tooth.

Common names of members

Mountain beaver.

Distribution

North America.

Size

Adults typically weigh between 500 and 900 g. With a tail length of 1-4 cm, the overall length is between 30 and 50 cm.

Morphology

They resemble beavers in appearance and are typically dark gray or brown, though depending on the subspecies, their fur can vary from being somewhat more reddish to being more blackish. They also have a light patch under each ear. The animals' tails are notably short. A few adults weigh more than 1,000 g.

Habitat & Ecology

Sea level to the tree line is their range. Although they are found in both coniferous and deciduous woods, they seem to favor the former over the latter over most of their range.

Diet

They seem to be exclusively herbivorous; the majority of their diets most likely consist of ferns, along with new shoots from more woody plants and mushy herbs. To get the most nutrition, they practice coprophagy and consume soft fecal pellets; hard fecal pellets, however, are moved to fecal chambers found inside the burrow system.

Reproduction

Two or three young are born in February and April during the breeding season, which runs from January to March. A month is dedicated to gestation and a few weeks to ovulation. The young are pink, hairless, and blind at birth. After six or eight weeks, they are weaned and soon after depart the burrow. Rodents have fairly lengthy life spans, ranging from 5 to 10 years. Their home ranges may overlap, but they are not gregarious beings. Although they are primarily solitary animals, mountain beavers have been known to form groups when food sources and adequate habitat are concentrated in a limited region; as a result, population numbers vary greatly.