Bactrian camels have two small, conical humps, small ears, and small feet with no chest or leg callosities, which makes the legs appear to be very long. Camels have evolved to cope with life in near-desert and desert conditions. Their nostrils can be closed to keep the blowing sand out. Their humps store energy as rich fats, making it possible to go long periods without food. Thick fur and wool provide warmth during cold winter nights and insulation against daytime heat. The camel differs from other hoofed mammals as the body rests on sole-pads rather than on hooves; only the front ends of the hooves touch the ground. When they do drink, camels can take in 30 gallons at once.