Wednesday, 13 June 2012

Dog domestication may have helped humans thrive while Neandertals declined

http://www.americanscientist.org/issues/id.15294,y.0,no.,content.true,page.1,css.print/issue.aspx

In my chapter in NAC called "The Ape That Domesticated Itself" I deal with the various hypotheses to explain when and how dogs became domesticated. In this fascinating, if very arguable, piece, Pat Shipman details more recent research on dog origins including dating work on finds from several European sites that shows that dogs were buried with full ceremonial honours in human encampments between 35,000 and 23,000 years ago. The relationships with dogs might have begun even earlier, she says, and might have been unique to Homo sapiens because no dog remains have ever been found at Neanderthal sites. Shipman details a lot of recent research which shows that dogs large and small can increase hunting efficiency many-fold, bringing huge extra nutritional benefits to humans - especially gestating mothers - even after accounting for the amount fed to the dogs. We all know about the extraordinary level of communication that exists between humans and dogs, and dogs' uncanny ability to fasten onto and follow human cues - even direction of gaze. What might have facilitated gaze communication between dogs and humans? Shipman points to the evolution of the whites of the eyes - the sclerae - which are absent in chimps (except for one or two rare mutations). If a fortuitous mutation in sapiens' history led to the formation of sclerae this would have accelerated and tightened the bond between dog and man, improved their ability to work as a combined hunting unit, contributed to human nutrition and perhaps proved the edge that Homo sapiens enjoyed over the Neanderthals! Shipman admits there is no evidence to back up this last part of her tale - but it is a rattling, and thought-provoking just-so story - and may be a lot more!