The star-nosed mole is the world’s fastest-eating mammal. It takes less than a fifth of a second for it to identify if an object is edible and gobble it up. The secret is the ring of 22 tentacles around its nose. These are covered with 25,000 super-sensitive touch receptors, called Eimer’s organs. Working in total darkness in a tunnel, or underwater, the mole can discriminate between an edible larva and a stone or empty shell in 17 milliseconds. This is so fast that its brain is working almost at the physical limit of the nerve fibres. Star-nosed moles use this ability to eat very small insects and crustaceans that wouldn’t be worth the effort for a slower diner. They are also excellent swimmers and maintain a network of riverbank tunnels up to 270 metres (886 feet) long.