Beaver breeder Derek Gow, from Launceston, Cornwall, told the Mirror: "This is a very rare find.
"It's not one of ours. But beavers bring so much pleasure to people's lives and are important to Britain's ecology."
The beaver is a primarily nocturnal, large, semi-aquatic rodent.
They are known for building dams, canals, and lodges (homes), and their colonies create one or more dams to provide still, deep water to protect against predators, and to float food and building material.
They are the second largest rodent in the world after the capybara.
Breathtaking British wildlife photographs
Wild beaver spotted in England for first time in 500 years
Did you know? The male has a blue abdomen with black spots, while the female has a yellow or bluish abdomen with dark markings.
Did you know? The best place to spot puffins is at a breeding colony. You can see them at the RSPB's Bempton Cliffs (North Yorkshire) and South Stack (Anglesey) reserves, plus the Farne Islands (Northumberland), the Isle of May (off the Fife coast) and the Shetland and Orkney Islands.
Did you know? Common seals eat around three to five kilograms of food per day and have a varied diet of sandeel, cod, sprat, octopus and squid.
Did you know? The Orkney population of hen harrier is polygynous and males sometimes simultaneously mate to multiple females.
Did you know? The basking shark is the second biggest fish after the whale shark and is not the fastest of swimmers, travelling at around three miles per hour.
Did you know? The red deer is Britain's largest land mammal and the size of a stag's antlers is related to the quality of its diet. Stags living in forests have larger antlers than those grazing on moorland.
Did you know? Its scientific name Halichoerus grypus means 'hooked-nosed sea pig'. Its name grey seal can be misleading as the animals vary in colour, from black to cream.
Did you know? In summer black-tailed godwits have bright orangey-brown chests and belliers but change to a more greyish-brown in winter.
Did you know? It is believed the red squirrel's long tail helps keep its balance and steer when it is jumping from tree to tree, and may also keep it warm while it sleeps.