The European Beaver (Castor fiber) was once widespread across Europe and Northern Asia.

It had become extinct in Wales around the 12th century, due to over-hunting for its meat and fur - not because it was considered a problem species nor because of habitat loss.

Medieval woodcut of European beaver, illustrating contemporary beliefs
about its timber transporting prowess

Glandular oil (castoreum) from the base of its tail is rich in salicylic acid, a basic ingredient of modern aspirin drugs, and was widely used in medieval times as a treatment for headaches.

The beaver is mainly nocturnal and aquatic, with the capacity to remain underwater for up to 15 minutes at a time. It has waterproof fur, webbed hind feet and a flattened hairless tail.  

As the largest rodent in Europe, its overall length is 100-140 cm and it has a lifespan of around 10 years in the wild.  

A beaver with his spring greens [Photo courtesy Roy Dennis]

Beaver are exclusively vegetarian. They prefer eating aquatic plants, herbs and shrubs. Leaves, branches and bark of trees such as birch, oak, rowan, alder and willow also form part of their diet - and they are especially partial to aspen and poplar. Conifers are rarely chosen.

Beaver normally live in small family groups of 3-5 individuals. Around 2-5 'kits' are produced annually, with the young generally leaving their parents in their second year.