Why do mice gnaw things they can’t eat?

I don’t consider the wood mice and voles that invade my house as vermin – they’re not smelly like house mice or noisy like rats, and our food is pretty secure and out of their reach. But one habit is annoying, costly and potentially hazardous, and unfortunately it’s something all rodents do obsessively: chewing. They’re even named for it –

rodere is Latin for the verb ‘to gnaw’. There’s very limited nutritional value in wood and zero in plastic. So why do they do it? The answer is in the specialist nature of rodent teeth, which continue to grow from the root throughout life and thus need to be worn at the tips at the same rate. Feeding provides some of this abrasion, but often not quite enough. Regular gnawing does the rest and also maintains the razor-sharp edge of the chisel-like front teeth (the incisors), by wearing the dentine on the back of the teeth at a slightly faster rate than the harder orange enamel that covers the front. Amy-Jane Beer

Despite their name, wood mice – also known as long-tailed field mice – commonly enter houses.