A rabbit’s ears serve two key functions. First – and obviously – they help the animal to monitor its environment and detect predators. Rabbits can pick up sounds over considerable distances, perhaps up to 3km. Their ears can be rotated 270 degrees to help detect the source of a sound, and can revolve independently to monitor different noises.
Second, they assist in thermoregulation. A rabbit’s ears contain an extensive network of blood vessels that provide a large surface area for heat exchange. These vessels swell (vasodilation) when the rabbit is hot, and contract (vasoconstriction) when it is cool, so much so that they are barely visible in cold weather.
Rabbits are native to Spain and southern France, but have been introduced to many other parts of the world. Though they differ in size across the globe (those in Australia and Britain are 50 per cent larger than those in Spain), ear length is relative not to body proportions but to climate: in Britain they are 60–70mm long, in Spain about 75mm long, and in the arid parts of Australia roughly 80mm long, to help the animals cope with the hotter conditions.
Main image: European rabbit. © James Warwick/Getty