What mammal has the largest ears relative to body size?

The fennec fox has the largest ears relative to body size among mammals commonly featured in wildlife trivia. Native to the deserts of North Africa, this tiny fox has ears that can reach roughly 15 centimetres long, making them look oversized compared with its head and body.

Those ears are useful in two ways. Their large surface area helps release excess heat in the hot desert climate, while their exceptional sensitivity helps the fox detect insects, rodents, reptiles, and other prey moving beneath sand. The fennec can also use its keen hearing to locate prey that it cannot see.

The fennec fox is the smallest fox species and one of the smallest members of the dog family. Its pale fur reflects sunlight, and thick fur on its paws helps protect it from hot sand. The ears are sometimes confused with those of jackrabbits, but jackrabbits are hares rather than foxes. Elephants have much larger ears in absolute size, while the fennec wins the comparison when ear size is measured against body size.