All wild cattle have a keen sense of smell, and the yak is no exception. Yaks are constantly sniffing to collect information about each other, their enemies, and food sources. Males spend a great deal of time watching other males to assess their ability to fight. They use posture and movement to challenge each other, because they don’t have enough facial musculature to change their expressions. Often the challenges are between yaks of unequal strength: that way the weaker one can back down, and neither yak gets hurt. Yaks are grazing animals, and do not hunt. They are surprisingly agile, however, and have been known to slide down snowy hillsides, swim rivers, and make small jumps — maneuvers that might not be expected from animals that weigh over a thousand pounds and stand six feet high at the shoulder. Like domestic cows and bison, yaks feed on grass. Many of them are kept domestically by people like the Sherpas of Mt Everest, and the Sherpas see to it that their yaks find plenty to eat, even in cold weather. Yaks are very strong, and can carry heavy loads for people. Their horns and three-foot-long hair can be made into a variety of useful items. Usually one calf is born to a female yak, or ‘dri’, at a time, although twins do occur. The dri’s milk is very rich, and calves grow quickly. People make use of the yak’s milk as well — a yak can be milked three times a day. Yaks are found in the cold, dry regions of the Tibetan Plateaus in Central Asia. Often they are found at altitudes higher than 16,000 feet. Their blood is much thinner than that of most mammals. This allows them to easily maintain more of the scarce oxygen in their systems without having to breathe harder, as most mammals would have to do. As domestic animals, the yak’s future is assured. At one time they were hunted nearly to extinction, but the native people of the highlands discovered that farming the yak was a much more productive way of using it as a resource. Wild yaks do occur in smaller numbers, and if nothing changes, they always will.