July 30th, 2010

What Dogs Gave Us

We domesticated dogs. And dogs, in return, made human civilization possible.

Work with me here. A lot of my recent reading has been about human origins, stemming from my fascination with Homo Neanderthalis and what became of him. Two books of note: The Third Chimpanzee by Jared Diamond (1993) and Before the Dawn by Nicholas Wade (2007.) Jared Diamond is always a good read, and even though the book is showing its age I strongly recommend it. Wade covers much of the same turf, but does so with the tools of DNA analysis that simply didn't exist twenty years ago, when Diamond was doing his research. By counting mutations and working backwards through Y (male) chromosomal DNA and mitochondrial (female) chromosomal DNA, we can infer a great deal about human populations, where they came from, how they changed, and when. Of some of it I'm dubious--the extrapolation about the sources of human language, for example, seems a stretch--but most of it is no longer controversial, nor even exotic.

Both authors draw on anthropological research of stone-age peoples who survived into the 20th century. (Diamond did a lot of that research himself, in New Guinea.) The picture they paint of early humanity is grim: We are not fallen angels. We are risen apes. The hallmark of early humanity was deliberate genocide: New Guinea tribesmen told Diamond straight-out that their overall tribal goal was the extinction of other tribes. The homicide rates among such tribes are many times that of the homicide rate in Detroit; men who cannot claim to have killed another man often cannot persuade women to marry them. This seems to have been the pattern for hunter-gatherer societies as far back as we can see via the fossil record. Many Neanderthal skeletons show the marks of multiple healed bone and skull fractures, and a couple of them evidence of spear impingement on bone. Constant warfare was the pattern, and the method (judging from modern stone-age peoples) was the dawn raid: Raiders would stealthily draw close to a rival tribe's encampment, and wait for the rivals to turn in. Then, when there was just enough dawn light to move well, the attackers would fall upon the sleeping rivals and spear them where they lay.

This worked, and worked well. People have to sleep, so the attackers had the advantage. Then one day about 15,000 years ago, something unexpected happened: Animals around the rival encampment sensed the attackers creeping in for the kill, and set up a huge and unfamiliar racket. The rival group, awakened by the animals, grabbed their spears and gave chase. The attackers had been up all night waiting for just the right moment. The defenders had just had a good night's sleep. They could outrun their sleepy-eyed assailants, who had a ways to go to return to their home turf. More than a few attackers probably took a spear through an eye socket, and once enough of your dawn raiders take a spear through an eye socket, dawn raiding becomes a lot less compelling.

All because of some previously unknown animals who looked like wolves but made noises that wolves did not make--and appeared to consider the rival camp to be friends rather than food.

As best we can tell, dogs were first domesticated about 15,000 years ago, which was just about the time that Homo Sapiens was moving from wandering hunter-gatherer societies to settled societies that eventually became agricultural and pastoral societies. Just how they were domesticated is still unknown, but the work of Belyaev and his silver fox suggests simple selection by temperament: Ancient wolves became camp followers, and ancient humans tossed them scraps. Wolves who could stand to be near humans ate better without working as hard and had more pups. The few stone-age tribes we've been able to study sometimes captured wild animal juveniles and kept them as entertainment until they became grouchy on maturity. Dogs need to be handled as puppies to be fully at peace with humanity as adults; perhaps those wolves-in-transition descended from adult wolves who were handled by humans as pups and remembered: Those two-legged whatchamacallits handled me without hurting me--and they toss me aurochs bones!

15,000 years ago, that was a helluva deal if you were a wolf.

Explaining the bark is tougher, but group selection suggests that if some quirk in the genes of certain wolves allowed those two-legged whatchamacallits to survive and thrive, there'd be more aurochs bones and more yappy wolf/dog pups. Evolution works fast: Belyaev turned wild fox into peculiar (though not completely domesticated) pets in only 40 years, simply by selecting fox who were most willing to be handled when young and least snarly and aggressive when mature. A fox who will lick your face instead of biting your nose off is most of the way to a dog anyway; in another hundred years, he'd be sleeping at the foot of your bed and fetching tennis balls.

The bottom line is this: Without dawn raids, settled living rather than wandering became possible, and settled living fostered the development of villages and agriculture and trade and writing and all the other precursors of the lives we live today.

The Neanderthals had bigger brains than we do. What they didn't have were dogs. And, lacking dogs, the unfortunate louts dawn-raided one another to extinction, leaving homo sap and his faithful yappers to pick up the turf and eventually take over the world.

Raise a glass of Laughing Lab Ale to canis familiaris: Everything we are we owe to him. Good dog!