About

Beavers are Britain’s largest rodent, the group of mammals that includes rats, mice, and voles. They live in freshwater habitats, like rivers and streams, and prefer areas surrounded by wetland plants, trees and woodland. They are rather slow on land but excellent swimmers, so they feel safest when they’re close to deep water (around 70cm deep). If the water isn’t deep enough for them, beavers can make it deeper. They use mud, wood, and stones to build dams across shallow rivers, streams and ditches. The dams are leaky and let some water through, but slow down the flow enough for ponds to form, where the beavers can live and feel secure.

Beavers often shelter in burrows dug into a riverbank, with an underwater entrance tunnel. Some of these can be enlarged into bank lodges. If the bank isn’t suitable for a burrow, they can build a lodge from woody debris, twigs and soil. The lodge could be on a riverbank, or out in the middle of a beaver-built pond. A lodge offers a safe place to eat, sleep and raise young.

Beavers live in small family groups, formed by a pair of adults and any young they’ve had that year, and sometimes the young from the previous year, too. Pairs usually stay together for life. Breeding takes place between December and April and the pregnancy lasts for 103-108 days. Females give birth to their litter of 1-6 young in early summer (the average litter is 2-3 young). The young, called kits, reach sexual maturity at two years old, but don’t tend to breed successfully until they’re at least three.

Beavers are herbivores, feeding entirely on plants. In summer, they prefer pond weeds, grasses, leaves and other parts of plants. In winter they eat the bark of trees, favoring willow, poplars and alder. They have iron in the enamel on their teeth, which gives them extra strength for gnawing through wood, as well as making them a distinctive orange colour. They are crepuscular, meaning they are most active at dawn and dusk.

Beavers will also create a food cache in autumn in preparation for winter, to ensure they have enough to eat over the colder months. A food cache consists of branches and twigs, which are stored underwater by pushing them into the floor at the bottom of the waterbody, close to the entrance of their lodge.

Beavers are known as a keystone species – a species that plays a critical role in creating thriving ecosystems from which a wealth of wildlife benefits. By creating dams, making ponds, and forming canals to swim around their territory, beavers create habitat that helps lots of other wildlife to thrive, including water beetles, birds, bats, frogs, and fish. Their dams can also prevent flooding further down the river, keep water flowing during droughts, and even filter the water passing through them.

Beavers were once found throughout Britain, but were hunted to extinction in the 16th century for their fur, meat, and the oil in their scent glands, which was used in medicine and even perfumes. But now beavers are back! Thanks to the work of The Wildlife Trusts and other conservation charities, they have been reintroduced to Scotland. Many Wildlife Trusts are also running projects with enclosed beavers on nature reserves in England and Wales, with the ambition that one day beavers will be widespread in the wild once more.