Dear Click and Clack (Do you actually know who is who?):
In a recent program you made some disparaging comments about yak husbandry while giving some good advice re: letting a gas tank run nearly dry. I'll have you know that yak husbandry is an honorable and essential undertaking by the Himalayan hill tribes of Nepal and Tibet. There, in the foothill elevations of around 2000-3000 m, oxen are used for plowing and donkeys or mules for transportation.
In the high Himalayan elevations (3500-5000m) the yak (male) is used for burden and plowing and the nak (female) is used for milk.
In the middle elevations (3000-4000m) a sterile crossbreed of cattle and yaks is used. The male is the chopyok and the female is the changri (a possible origin of "Shangri La").
Hoping this will be of vital interest to you and your listeners,