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May 28, 2009

Floppy ears are probably genetically linked to friendliness

Early in the process of domestication, Belyaev noted, most domestic animals had undergone the same basic morphological and physiological changes. Their bodies changed in size and proportions, leading to the appearance of dwarf and giant breeds. The normal pattern of coat color that had evolved as camouflage in the wild altered as well. Many domesticated animals are piebald, completely lacking pigmentation in specific body areas. Hair turned wavy or curly, as it has done in Astrakhan sheep, poodles, domestic donkeys, horses, pigs, goats and even laboratory mice and guinea pigs. Some animals' hair also became longer (Angora type) or shorter (rex type).

Tails changed, too. Many breeds of dogs and pigs carry their tails curled up in a circle or semicircle. Some dogs, cats and sheep have short tails resulting from a decrease in the number of tail vertebrae. Ears became floppy. As Darwin noted in chapter 1 of On the Origin of Species, "not a single domestic animal can be named which has not in some country drooping ears" - a feature not found in any wild animal except the elephant.

Another major evolutionary consequence of domestication is loss of the seasonal rhythm of reproduction. Most wild animals in middle latitudes are genetically programmed to mate once a year, during mating seasons cued by changes in daylight. Domestic animals at the same latitudes, however, now can mate and bear young more than once a year and in any season.

The amazing story of the silver fox and Dmitry K. Belyaev, which provided evidence that simply selecting for friendliness could create many of the common features of domesticated animals. I first read an astonishing article about this as an undergraduate, but I haven't been able to find it since. I wonder if this is it. Thanks to Shepherd either way.

Update:
Checking out the article with pictures, I'm now pretty sure that this was the article
Early Canid Domestication: The Farm-Fox Experiment

Posted by OneEyedMan at May 28, 2009 5:28 PM

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Posted by: Monk at May 28, 2009 6:26 PM

Posted by: Monk at May 28, 2009 6:34 PM

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