Six Eurasian beavers released into an enclosed reserve as part of a conservation project in Gloucestershire two years ago have begun to breed.
Beavers help create new growth by gnawing down trees
The beavers were brought to the Lower Mill Estate in the Cotswold Water Park from Bavaria in 2005.
"They do such a great job for the environment, they manage the eco system by dead-wooding and creating new growth," said land owner Jeremy Paxton.
Beavers had been absent from England for about 500 years.
The animals were hunted almost to extinction for their thick fur.
The estate owners are not allowed to release the beavers into the wild because they are not native species.