Beaver believers

The British experience of beavers is somewhat limited. Most of us haven’t been lucky enough to have spied an immigrant rodent in the wilds of west Devon, or paid a visit to Knapdale and Alyth in Scotland. Instead, we’ve only met beavers in storybooks, notably The Lion, the Witch and the Wardrobe, where in the warm, homely hut of Mr and Mrs Beaver, the Pevensie children are first introduced to the prophecy of Aslan, over fish and potatoes and a sticky marmalade roll.

Needless to say, beavers don’t eat marmalade — they don’t even eat fish. Yet these tree-chewing, dam-building rodents are still useful, hospitable creatures, and not just for their pelts, although that’s something humans have occasionally forgotten over the years.

There’s a lot of history to them. They evolved 30 million years ago — here long before we appeared on the scene around 300,000 years ago. That means, rather excitingly for imaginative sorts, humans were around when beavers the size of hippos roamed from Florida to Alaska.

Eager is peppered by facts like this, as we follow the environmental journalist Ben Goldfarb on a historical, ecological and geographical journey across North America, Britain and Europe, exploring the role of beavers as a keystone species. Remove such a species and the entire ecosystem suffers.

Eager is the story of why the American (and to some extent European) landscape looks the way it does — because of those mountain men and fur trappers who rampaged across North America 400 years ago, killing beavers for their soft fur and mindlessly altering the topography of the continent simply because of the European fashion for beaver hats.

This flat-tailed creature was hunted in Europe long before that, prized not only for its pelt but for meat and medicine.