Why Do the Ears of a Fox Point Forward?

Foxes are small, primarily carnivorous mammals of the dog family. They range in size from the tiny African fennec to the European red fox. Diet includes birds, rabbits, mice, grasshoppers and other insects, earthworms, eggs and carrion. Foxes also forage on fruit, berries, nuts and grasses. They are solitary animals that hunt alone. Most species have pointed faces with erect, triangular ears, short legs, thick fur and a long bushy tail.

Most members of the canine and feline families have ears that point forward. The forward-pointing ear is an evolutionary adaptation that is linked to the animal's methods of hunting. Foxes quietly stalk their prey, attempting to get as close as possible before pouncing. If they do not succeed in catching it, they will give chase. A fox can run up to 25 miles per hour to catch rabbits and other small mammals. Forward-pointing ears allow the predator to hear its prey even while moving forward to stalk or chase.

Foxes have an acute sense of hearing that they use to detect prey. Unlike most mammals, they can detect the low-frequency sounds of small animals digging beneath snow or under the ground. The fox tilts its head to focus its ears, locates the source of the sound and digs up its prey.

Grazing animals, including rabbits, are vulnerable to predators, like the fox, that sneak up close to them while they eat. The ears of such prey animals have evolved to be large, exceptionally mobile and capable of moving independently, allowing them to hear sounds from both sides and from behind. As they graze, their highly mobile ears swivel constantly to catch any hint of potential predators.

Fox species that live in extreme environments of hot or cold have evolved variations in the shape and size of their ears. The fennec of the African desert and the kit fox of the American Southwest have enormous ears that dissipate heat and help to regulate their body temperature. The arctic fox has evolved small rounded ears that conserve heat and are less subject to freezing.

Not only do predators have ears that point forward, they also have eyes on the front of their faces, giving them binocular vision to better focus on the prey in front of them. Their prey, by contrast, have ears and eyes on the sides of their head. They can see and hear potentially dangerous movement from behind and on either side.