Bactrian camels have two humps rather than the single hump of their Arabian relatives. The humps function the same way—storing fat which can be converted to water and energy when sustenance is not available. These humps give camels their legendary ability to endure long periods of travel without water, even in harsh desert conditions. As their fat is depleted, the humps become floppy and flabby.

Bactrian camels live not in shifting Sahara sands but in Central and East Asia's rocky deserts. Temperatures in these locales can become searingly hot—over 100°F (38°C) in summer. Yet they can also drop to –20°F (-29°C) in winter. Bactrian camels have developed special adaptations to allow them to survive in such a brutal environment. One is a thick, shaggy coat that protects them in winter and falls away as seasons change and temperatures rise.

Like Arabian camels, Bactrians rarely sweat, helping them conserve fluids for long periods of time. In winter, plants may yield enough moisture to sustain a camel without water for several weeks.

When camels do refill, however, they soak up water like a sponge. A very thirsty animal can drink 30 gallons (135 liters) of water in only 13 minutes.

Like Arabian camels, Bactrians' nostrils close to keep sand at bay, and their bushy eyebrows and two rows of long eyelashes protect their eyes. Big, flat footpads help them navigate the rough rocky terrain and shifting desert sands without sinking under their own massive bulk or the weight of heavy packs.

The only truly wild camels that still exist are Bactrian camels. These herds survive in the Gobi Desert of Mongolia and China but number less than 1,000