Seven years ago, back in November of 2008, we wrote Why Are the Neanderthals Extinct? We mentioned various Neanderthal extinction hypotheses, and then we suggested that the answer to that question was dogs — humans formed an early and mutually beneficial relationship with dogs while the Neanderthals never did, and that is what made all the difference. We hypothesized:
[N]ot only are we responsible for the existence of dogs, but our own survival is due to the natural selection of our ancestors for their dog affinity. The two species selected each other and mutually contributed to our joint evolution — an example of what biologists call coevolution. Those humans who befriended dogs are the ones that survived. They outlived the Neanderthals and became our ancestors. Our natural liking for dogs is literally part of our human nature.
This hypothesis — that dogs helped us survive while the Neanderthal failed — requires that humans and dogs were routinely living together — or at least in close, cooperative proximity — as far back as 30K years ago, when the Neanderthals went extinct.
This idea that we are indebted to dogs for our survival and our predominance over the Neanderthal must remain an hypothesis, as it can’t be supported by the mere absence of evidence of a Neanderthal-dog association. All we can say is that no such evidence has yet been found, so our hypothesis is viable.
Since then we’ve seen others suggest the same thing, e.g., The Invaders: How Humans and Their Dogs Drove Neanderthals to Extinction, by Pat Shipman.
Our biggest problem was finding clear evidence that humans and dogs co-existed in Europe 30,000 years ago, when the Neanderthals went extinct. We briefly thought that may have been resolved by this article we just spotted in The Telegraph of London. Their headline is Dog has been man’s best friend for 33,000 years, DNA study finds. Here are some excerpts, with bold font added by us:
Man’s best friend came about after generations of wolves scavenged alongside humans more than 33,000 years ago in south east Asia, according to new research. Dogs became self-domesticated as they slowly evolved from wolves who joined humans in the hunt, according to the first study of dog genomes.
And it shows that the first domesticated dogs came about 33,000 years ago and migrated to Europe, rather than descending from domesticated European wolves 10,000 years ago as had previously been thought.
Aha — that would place dogs in the picture back when Neanderthals still existed. But south-east Asia is a long way from Europe. Then we’re told:
So in one of the largest studies of its kind Professor Peter Savolainen and colleagues sequenced the genomes of 58 members of the dog family including grey wolves, indigenous dogs from south-east and north-east Asia, village dogs from Nigeria, and a collection of breeds from the rest of the world, such as the Afghan Hound and Siberian Husky.
The DNA analysis published in Cell Research found those from south-east Asia had a higher degree of genetic diversity, and were most closely related to grey wolves from which domestic dogs evolved. Prof Savolainen, of the Royal Institute of Technology, Solna, Sweden, said this indicates “an ancient origin of domestic dogs in southern East Asia 33,000 years ago.”
Here’s the paper in Cell Research: Out of southern East Asia: the natural history of domestic dogs across the world. You can read it online without a subscription, but we’ll stay with The Telegraph, which reports:
The researchers said around 15,000 years ago, a subset of ancestors [of dogs, presumably] began migrating towards the Middle East and Africa, reaching Europe around 10,000 years ago.
Ooops — that’s much too late to affect the Human-Neanderthals situation in Europe. Let’s read on:
Although this dispersal is believed to have been associated with the movement of humans, the first movement of man’s best friend out of south-east Asia may have been self-initiated.
Huh? Dogs migrated by themselves? Ah well, this is from the article’s end:
Earlier studies have suggested wolves may have been domesticated by the first farmers about 10,000 years ago in the Middle East or Asia, possibly to guard livestock. But the latest study has found it began much earlier, long before the development of agriculture.
Looking for better evidence for our hypothesis that dogs and humans co-existed in Europe 30,000 years ago when the Neanderthals went extinct, we turned to the published paper. The abstract says:
Around 15 000 years ago, a subset of ancestral dogs started migrating to the Middle East, Africa and Europe, arriving in Europe at about 10 000 years ago.
No help there. Let’s see if we can find any encouragement in the paper itself:
As there is little evidence of westward human migrations from southern East Asia around 15 000 years ago, the initial spread of the domestic dog out of Asia may in part have been a self-initiated dispersal driven by environmental factors (e.g., the retreat of the glacial coverage that started about 19 000 years ago). The specific route domestic dogs used to migrate to the Middle East, Africa and Europe remains to be uncovered. Some of this dispersal might be heavily influenced by humans, as dogs were often part of the civilization package that traveled together as agriculture spread. Further studies using samples from western Eurasia should reveal insights into these early dog migrations.
That leaves the door partially open for our hypothesis, because we know humans were present in Europe well before 30,000 years ago. Cro-Magnon fossils have been found in Europe dating to as far back as 45,000 years ago. But what about dogs? Ah — the door opens a little wider. The published paper says:
Nevertheless, it is possible that multiple primitive forms of the dog existed, including in Europe. However, in this case, the genetic pattern presented here shows that those lineages were replaced by dogs that migrated from southern East Asia, and thus made negligible contributions to the modern dog gene pool.
So the Curmudgeon’s hypothesis remains viable — to some extent. That will do, until further evidence is found.
Copyright © 2015. The Sensuous Curmudgeon. All rights reserved.