ON THE WILD SIDE
MR Average can hold his breath underwater for less than a minute. Otters can hold theirs for eight, a beaver for
15. But the grey seal can hold his for an incredible
30mins.
There are only two species of beaver – the European and the North American.
They look the same but are eight chromosomes apart, which means genetically they are as alike as humans are to cats and cannot breed.
The last British beavers were hunted to extinction in the 1700s, with the final skull handed to the Church for a bounty payment in 1789.
They were considered a nuisance animal and were hunted for their meat, fur and castor sacs.
Castors are found in pairs in a beaver’s bum and are used to mark territory.
People decided that their contents, castoreum, were great for adding to food, medicine and even perfume.
Some perfumes still use it. If you ever see a scent that claims to smell of leather, it is probably made with castoreum. Beavers are well known for their habit of chewing tree trunks and using them to make dams.
They need to chew to grind down their teeth. Without doing so, their teeth grow at a rate of well over 3ft a year!
One beaver family can cut down 300 trees a year. Some tree species, like their favourite willow, grow back stronger when they are cut.
Beavers build 3ft-high dams which make slow-flowing pools in rivers. These provide environments where fish, water voles, otters and dragonflies can thrive, as well as making rivers far less likely to flood in heavy rain.
These pools also filter out pollutants from the water.
In the late 2000s, beavers showed up at two UK locations. Five appeared in Devon, and a colony popped up in eastern Scotland.
Other planned reintroductions have taken place, but these animals are usually in enclosed areas where their impact can be carefully studied.