All the breeding females in a population ovulate at the same time each year. Although they are furry by two weeks and begin to crawl using their strong front legs at l5 days, their eyes remain shut for nearly two months. Bobcats, mink, and long-tailed weasels have been listed as the main predators of mountain beavers. Wildlife biologist Christopher Servheen added golden eagles when he discovered that logging activity provided expanded habitat for both mountain beavers and the eagles. The two species have been brought together by deforestation.
Coyotes also prey on mountain beavers following forest fires and heavy logging activity.
Except for the subspecies A. r. nigra found at Point Arena in Mendocino County, which may include fewer than 500 individuals and is on the federal endangered species list, most of these adaptable rodents are doing well. Perhaps too well for their own good. They are able to survive clearcuts due to their subterranean lifestyle and preference for new growth. In fact, despite deforestation in the Northwest, most mountain beaver populations appear to have increased thanks to their ability to feed on seedlings and other juicy plants that thrive in burned and deforested areas. The Amazing World of Lemurs, Monkeys and Apes , will be published by Chronicle Books this fall.