While they are eating, they squat and emit hard and soft pellets which they catch in their mouths. Reproduction Beginning in November or December, there is an increase in the size of the testes, prostate and bulbourethal glands of males. As females reach estrous, their nipples increase in size, their vulva swell, and vaginal smears reveal predominately ephithelial cells. Females that are only a year old ovulate as well but no breeding occurs, demonstrating that ovulation is spontaneous instead of being triggered by copulation. The onset of the estrous cycle is around February or March.
Gestation usually lasts six to eight weeks and litters of two to three young are common.
The weight of the young beavers is 25.5g. At birth, the beavers are pink, helpless, blind, and do not have a considerable covering fur. Behavior Mountain beavers are not very social animals. Rarely do they go farther than a few meters from their burrows. Their home ranges overlapand each beaver defends its nest site.