Yak Science

Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Artiodactyla
Family: Bovidae
Subfamily: Bovinae
Genus: Bos [ox]
Species: grunniens [grunting] (domestic), mutus (wild)

Yaks thrive at altitudes ranging between 10,000 and 20,000 feet. They have adapted genetically to high elevations, and do not experience the symptoms of hypoxia (altitude illness). Yaks can deliver sufficient quantities of oxygen to the brain and muscles in low-oxygen environments. This is because yaks have three times the number of red blood cells, and a higher concentration of hemoglobin than other cattle normally living in lower elevations. Yaks also have larger lungs relative to their body size, and even have an extra pair of ribs to house them - yaks have 14 ribs pairs compared to 12 in cattle. Complex muscles surrounding the chest cavity enables yaks to breathe deeply and rapidly which sounds like the chugging of a locomotive. Tibetan sherpas have claimed that yaks living in high altitudes descending to lower altitudes experience "low altitude" sickness. This illness is more likely due to exposure to lowland cattle diseases and parasites not common at high elevations.

Not only can yaks breathe well in the high altitudes of the Himalayas, but they can also withstand the frigid temperatures which can drop below -40° F. Yaks are protected by their thick, wooly undercoat, long fur, and outer fatty layer which insulates their body.

If the road was dubious, travelers drove a yak up it before them; the beast, being sure-footed, would detect any ravines and crevasses. Deep snow could be cleared for men and horses, by driving a score of yaks ahead of the caravan; they trampled the drifts down and made them a regular highway. If driven to warm pastures, the yaks were said to perish. Their favorite habitat was wherever the temperature stayed below freezing, on mountain slopes and summits. If the snow on the elevated flats was too deep for a grazing yak to dig through, it rolled itself down the slopes and ate its way up again. When it arrived again at the top, it merely somersaulted down, and started again at the bottom!

- De Fillipi, Himalaya Karakorum and Eastern Turkestan.

Although yaks are genetically adapted to high altitudes, they tolerate atypical conditions just as well, despite their reputation for poor adaptation to low elevations and high temperatures. Yaks are found thriving throughout the United States, some at an elevation of only 40 feet above sea level!

River was born in Satsop, Washington, home to a large yak herd thriving at an elevation of only 10 feet above sea level! River now lives at an elevation of 2,552 feet above sea level in Garfield, Washington. The summers in Garfield can be hot, but River fares well. On hot days he lays up in the shade or he wallows in muddy water holes in his pasture.

linoleum cut, block print by Tracy Paine