Domestication

“My working hypothesis,” says Greger Larson, an expert on genetics and domestication at Durham University in the United Kingdom, “is that with most of the early animals—dogs first, then pigs, sheep, and goats—there was probably a long period of time of unintentional management by humans.” The word domestication “implies something top down, something that humans did intentionally,” he says. “But the complex story is so much more interesting.”

In The Variation of Animals and Plants Under Domestication, Darwin wrote that domesticated animals share certain traits in common: floppy ears, smaller, curly tails, and often spotted coats. Those traits make the animals seem younger and are present in domesticated pigs, dogs, cows, chickens, and even some fish.

Domesticating the Fox

A wild fox.

Dmitry Belyaev took up 150 foxes to domesticate and with each generation, he selected the most approachable to breed. After only 9 generations of selecting strictly for friendly interaction with humans, the foxes were already showing signs of domestication  – actively bonding with humans, smaller, floppy-eared, curly-tailed, and spotted coats. They were also whining and wagging their tails in human presence.

Cuddly Foxes!!

These foxes also have the ability to follow human pointing and eye movements (an ability that domesticated dogs possess) suggesting that selecting for a nicer fox yields a smarter fox as well.

A cuddly house-fox!

Belyaev’s hypothesis: There exists a collection of genes that lead to tameness, this is a genotype that foxes share with any species capable of being domesticated.

The fox farm not only has cuddly friendly foxes, but also foxes bred for a mean disposition. They are all decidedly vicious. Then the researchers did a surprising test, had a vicious fox brought up by a tame mother; the result: a vicious fox. The conclusion: nature won over nurture.

The search for the tameness gene is proving difficult. First the genes responsible for friendly and aggressive behavior must be identified then analyzed for control over spots in fur, curly tails, and floppy ears. One theory is that these behavior altering genes alter chemicals in the brain and have downstream effects on physical appearance.

Domesticating the Rat

Belyaev also performed this experiment on rats.


Above, is result of 73 generations of breeding for hostility toward humans.

Belyaev’s Critics

Leif Andersson of Uppsala University argues that there may not be a causal relationship between the behavior traits and the physical traits of domestication. He argues that perhaps tameness to humans was selected for a some point, perhaps naturally because animals could benefit from living closer to humans by living off of their trash, or artificially by humans breeding friendly animals. Only after that initial selection for friendliness, humans begin selecting for cuter animals and the two traits are not linked.


all from national geographic article including all photos (except wild fox photo): http://ngm.nationalgeographic.com/2011/03/taming-wild-animals/ratliff-text/2
wild fox photo: http://www.alansaunders-wildlifephotography.co.uk/awardsacceptances-into-national-international-photographic