Tuesday, January 29, 2013

Yaks and Naks

Image from http://www.all-hd-wallpapers
Today, as I was once again swimming in the internet lagoon, I decided to scout out some information about yaks. Why yaks? I cannot say, but apparently, there are plenty of interesting things to note about this creature and how it is developed for its cold, highland environment.

You may already know that yaks are those woolly, mountainous beasts that resemble a mix between a cow, a bison, and a mammoth. Despite its lumbering appearance, wild yaks (Bos mutus) make a good living in their Himalayan home. They are generally solitary and will often run for miles if they sense a human approaching. However, yaks themselves are actually quite gentle in nature. If they feel threatened, a yak may make a false charge, which is much like playing the classic game of "chicken" where the yak will drift to the side at the last moment, avoiding collision.

Image from http://www.springbrook.com/
Such a large animal can afford this active highland lifestyle with a few adaptations. Yaks have a digestive system that runs at a higher temperature than, say, your regular cow, which allows them to burn the food that they eat in a sufficient manner. The lungs of the yak are built to hold a large capacity of air so that they can breathe (and run) at high altitudes, and their hearts are larger. Even the blood of yaks contains fetal hemoglobin, which has a greater affinity for oxygen than does regular hemoglobin when at low atmospheric pressure. The hooves of the yak are made for digging into the snow to grip firm ground beneath, which is probably why you will not see a yak tumbling down the slopes. The fur of the yak forms a dense mat on the bottom that helps to trap heat but makes the yak more susceptible to heat exhaustion in warmer climates. Yaks stay warm and dry because they have very few sweat glands.

Although I have been writing about wild yaks, domesticated yaks are widely used in Tibet as pack animals. They do the job quite well because they survive on less that 1% of their body mass each day (a cow requires 3%), and unlike a cow, a yak will not eat grain but must forage for grass. The Tibetans will burn yak dung for fuel. Also, in Tibet, there is a distinction between a male yak (called a "yak") and a female yak (called a "nak").

And, just because yaks are so fun, there is such a sport as yak skiing. It has a simple layout whereby you have a skier at the bottom of a slope and a yak at the top. The two are tied together via a pulley system that runs up the side of the mountain. The skier will shake a bucket filled with pony nuts (a delicacy among yaks), and the yak will come barreling down the slope, sending the skier shooting to the top. I would assume this ends with the skier skiing back down the hill while the yak wanders back up.

1 comment:

  1. You are doing great blog work here! Definitely standing out amongst PZ's students!