Ben Goldfarb is an American author, who describes himself as an environmental journalist and beaver believer. He also happens to be over here in the UK and, tonight, Jane and I attended a talk he gave on beavers at the University of Oxford’s Museum of Natural History.

I knew a few things about beavers, such as that their decline in the modern era was down to demand for their pelt and for their scent glands (castor sacs). However, there was plenty I didn’t know as well such as that scientists sex animals not by visual differences (both sexes are similar in weight and appearance with recessed genitalia) but by sniffing their scent (males apparently smell like motor oil and females like old cheese), or that their teeth are strong and tend towards orange because they are reinforced with iron. Apparently C S Lewis wasn’t entirely well-informed on beavers either as, unlike Mr and Mrs Beaver in the Chronicles of Narnia, they don’t eat fish but live on a herbivorous diet with a notable tree-based component (although some allowance should be made for the fact that they had plenty of other fictional characteristics too).

They also have a generally net positive effect the environment, slowing the flow of water downhill, which lets more of it soak into the ground and benefits a whole range of other creatures. Sometimes the results are at odds with what humans want, causing flooding in previously dry areas, but a bit of ingenuity can go a long way – one example was wire fencing to protect valued trees, which meant the beavers did a great job of weeding out the unwanted, invasive tree species.

A fascinating subject – and a very engaging speaker.