The one-humped camel is often called the dromedary. In the wild it is already extinct and survives only in domesticated form. It is used to carry heavy loads or as a means of transport. A typical feature of the dromedary is a single hump on its back, which absorbs heat and protects the animal from the sun. The hump also contains stored fat, whose breakdown releases energy and water. The one-humped camel is a large animal with long legs, measuring 2.2 to 3.4 m in length and weighing 450–550 kg. It has coarse, cream light-brown fur, longest on the crown, neck, throat, and hump, and a tail measuring 50 cm. Its eyes have double-layered eyelashes that protect them from sand entering the eyes. The average lifespan of camels is around 40 years.