This week’s snow and moderately colder weather made me recall a documentary I watched recently about domestic yaks in Siberia.
According to “Mammal Species of the World: A Taxonomic and Geographic Reference,” there is a difference between wild and domestic yaks. The domestic yak, Bos grunniens, is descended from the wild yak, Bos mutus. They are long-haired domesticated cattle found throughout the Himalayan region of the Indian subcontinent, the Tibetan Plateau, and as far north as Mongolia and Siberia.
The film showed how these beasts are adapted to winter when there is no running water to be found because it is all frozen. That would be a really big problem for modern cattle from the temperate zones.
It is not uncommon for domesticated cattle to suffer dehydration because of frozen water in winter months. This is especially true if they suffer additional weather condition challenges and a lack of food. Yes, this occurs even in the U.S.
The yak, however, deals with frozen water just fine. To thaw the ice, yaks place their noses down close to the ice and breathe onto the surface. All the long hair surrounding their mouths and noses forms a kind of insulated tunnel that holds the heat of the breath close to the ice for the few more seconds necessary to make small puddles of liquid.
Of course, yaks continually lap up the water before it refreezes. The lapping motion is very similar to that seen when dogs lap at a regular water bowl. At the same time though, that’s quite a bit of work to get enough water.
In the cold, obviously, food and water are key survival inputs while shelter, minimizing unproductive motion and maximizing heat retention work on the output side of the equation.
Productive motion means getting food and water. During Palouse winters, it is common to see many raptors waiting patiently on posts or even the ground for something to hunt. They shelter by finding the least windy spots and fluffing their feathers to provide more dead airspace insulation value. They orient their positions so as to catch as much of the sun’s warmth on dark feathers as they can. All such adaptations and more are managed to also ensure there is still a reasonable chance from that location to capture food.
Food is not for the picky predator either. Where there is food, alive or dead, it shall be eaten. If one really wants to see a lot of bald eagles, it is best done when they are least noble. High-desert winter kills of deer attract eagles like nothing else. It is common to see such a kill say in southeastern Idaho or central Oregon during a hard winter. There are often so many eagles around a carcass that they look like a wake of buzzards.
Raptors will feed on any dead animal during the colder months. Sadly, animals shot with lead bullets or pellets that escape may provide a food source. If eaten, lead is ground in the crop and can become toxic.
Yaks are far thriftier than our beef cattle. They need only eat about 1 percent of their body weight daily to maintain body mass, but beef cattle need about 3 percent. A yak’s ideal Mongolian/Siberian meal is native grasses. They do not eat grain. When winter rolls around, they spend a large portion of each day just trying to find enough to eat.
Charlie Powell is the public information officer for the Washington State University College of Veterinary Medicine, which provides this column as a community service.