More industrious than any other mammal besides humans, and larger than any other rodent in the United States, the North American beaver is becoming increasingly abundant in Bering Land Bridge National Preserve. With large webbed feet and a broad, scaly tail, these semi-aquatic mammals range in size from 2-3 feet long with about a 1 foot long tail and can weigh up to 60 lbs. A second set of transparent eyelids allows them to navigate underwater for up to 15 minutes at a time.
Beavers live in colonies of 2-12 individuals (usually related family groups) and are known for creating extensive dams and lodges that can totally alter entire stream systems and waterways. Using their continually growing front incisors to gnaw down trees, they build these structures primarily for protection against predators and to provide easier access to food during the winter. As nocturnal herbivores, their diets consist entirely of vegetation, such as leaves, bark, twigs, and roots, and will stash their food underwater to access it during winter months.
Historically, beavers have been one of the most commonly trapped mammals for their fur, to the point where they were eliminated from most of their range in the 1800s. Now that trapping is regulated their population remains around 6-12 million, though a far cry from the estimated 60 million that once inhabited the continent.