The Tibetan plateau is the roof of the world. Rising three miles into the sky, the air is intolerably thin, water is scarce, and temperatures regularly plummet to –40°F. No trees peep above the rocky, windswept landscape. Even hardy shrubs struggle to survive. Yet there they are, lots of them—massive hairy yaks munching away on meager scraps of grass and herbs, seemingly oblivious to their impossible situation. Wild males can be over 10 feet (3.25 m) long and tower over 6.5 feet (2 m) at the shoulders; their average weight is around 1 ton (1,000 kg).
With its dense, woolly undercoat and shaggy outer hair coat, the “grunting ox” (Bos grunniens) is well prepared to endure the raging cold that is characteristic of this remote region of Asia. Yaks can easily withstand temperatures of –40 degrees, that numbing condition where the Fahrenheit and Celsius readings are the same . . . if the thermometer goes that low. They have been seen bathing in lakes and rivers, regardless of the temperature.
These are cattle, but not like the barnyard variety you’re used to. Wild yaks are among the largest living members of the cattle family. (Females are about a third the size and weight of males.) Despite their intimidating stature and impressive horns, yaks are on the timid end of the cattle spectrum. They prefer to run away when they encounter humans.
Not only must they survive the cold, but they must function in the thin mountain air. Their home range is 12,800 to 19,200 feet (4,000 to 6,000 m) above sea level, where oxygen is limited and plant life is sparse. Few animals can survive at this altitude. Thanks to their caring Creator, however, yaks are adapted to their home high on the Tibetan plateau in a variety of ways.
They have a stocky build with short legs and broad hooves, making them excellent climbers as they travel great distances searching for food. They have a larger heart and lungs than cattle living at lower altitudes, enabling them to pump more blood and take in more air than others of their kind. Additionally, they continue to produce the specialized hemoglobin that they had in their mother’s womb because it enables them to extract more oxygen from their lungs and deliver it to body tissues despite these challenging conditions (more on that later).