Aidi wan n'Eezel: the loyal azawakh

Last summer I saw a DVD from the PBS show Nature called “Dogs that Changed the World” and also read the book of one of the contributing scientists. One of the really interesting parts of the miniseries was a discussion of the breeding program of a Russian scientist named Dmitri Belyaev which began in 1948.

Belyaev’s breeding program was designed to create a tame breed of silver foxes. As an aside, this was thought to have commercial implications because the raising of silver foxes in captivity for the Russian fur industry is difficult because the foxes are vicious.

What Belyaev did was select for a single behavior. The foxes that were least aggressive and avoidant were bred together. The result of this breeding program was that in just a few generations. Within a relatively small number of generations, by selecting only for temperament, Belyaev had created a very different stain of fox:

• They became dog-like and friendly with people
• Some of the tame foxes developed drop-ears
• The musky “fox smell” dissapeared
• They became white and black like border collies
• The pups begin responding to sounds 2 days earlier than wild type pups
• The pups open their eyes a day earlier than wild type pups
• Delayed onset of adult corticosteriod hormones levels (~8 months of age instead of 2-4 months of age)
• Their social behavior changed
• They wagged their tails when happy
• They began to bark and vocalize like dogs
• The tame foxes tended to have shorter tails and shorter legs
• Curled and double-curled tails developed
• Overbite and underbite developed
• The tame females came into estrus (heat) more frequently

The amazing takeaway point is that selecting for behavior and nothing else yielded dramatic cascade of apparently unrelated physical changes in the animals.

Incidentally, the physical changes make the fur of the tame foxes commercially useless. My understanding is that Belyaev has not been able to breed a tame fox that has the correct pelt for the fur industry and so the tame fox is not commercially viable.