Tuesday, January 29, 2013

This dog thing...are dogs people?


Dog History

How were Dogs Domesticated?

By , About.com Guide

Larry and Butch - A boy and his dog at the beach
Larry and Butch - A boy and his dog at the beach

Dog history is really the history of the partnership between dogs (Canis lupus familiaris) and humans. That partnership is based on human needs for help with herding and hunting, an early alarm system, and a source of food in addition to the companionship many of us today know and love. Dogs get companionship, protection and shelter, and a reliable food source out of the deal. But when this partnership first occurred is at the moment under some controversy.
Dog history has been studied recently using mitochondrial DNA, which suggests that wolves and dogs split into different species around 100,000 years ago: but whether humans had anything to do with that, no one really knows. Recent mtDNA analysis (Boyko et al.), suggests that the origin and location of dog domestication, long thought to be in east Asia, is in some doubt.

European Paleolithic Dogs

Part of the puzzle of the domestication of dogs lies in the Upper Paleolithic of Europe, beginning perhaps as long ago as 30,000 years.

Evidence of a Certain Domestication Partnership

A burial site in Germany called Bonn-Oberkassel has joint human and dog interments dated to 14,000 years ago. The earliest "nobody-argues-about-it" domesticated dog was found in China at the early Neolithic (7000-5800 BC) Jiahu site in Henan Province. European Mesolithic sites like Skateholm (5250-3700 BC) in Sweden have dog burials, proving the value of the furry beasts to hunter-gatherer settlements. Danger Cave in Utah is currently the earliest case of dog burial in the Americas, at about 11,000 years ago.

Dogs as Persons

A reanalysis (Losey and colleagues 2011) of dog burials dated to the Late Mesolithic-Early Neolithic Kitoi period in the Cis-Baikal region of Siberia suggests that in some cases, dogs were awarded "person-hood" and treated equal to fellow humans. A dog burial at the Shamanaka site was of a male, middle-aged dog (probably a husky) which had suffered injuries to its spine, injuries from which it recovered. The burial, radiocarbon dated to ~6200 years ago (cal BP), was interred in a formal cemetery, and in a similar manner to the humans within that cemetery. Losey and colleagues believe the dog may have lived with its human family at Shamanaka.
A wolf burial at the Lokomotiv-Raisovet cemetery (~7300 cal BP) was also an older adult male. The wolf's diet (from stable isotope analysis) was ungulates, and although its teeth were worn, there is no direct evidence that this wolf was part of the community. Nevertheless, it too was buried in a formal cemetery.
These burials are exceptions, but not that rare: there are others, but there is also is evidence that people of the Kitoi culture (late Mesolithic fisher-hunters in Baikal) consumed dogs and wolves, as their burned and fragmented bones appear in refuse pits. Losey and associates suggest that these are indications that Kitoi hunter-gatherers considered that at least these individual dogs were "persons".

Haplotypes and Grey Wolves

A recent study led by Robert Wayne (vonHoldt et al., below) at UCLA and appearing in Nature in March 2010 reported that dogs appear to have a higher proportion of wolf haplotypes from grey wolves native to the Middle East. That suggests, contrary to earlier studies, that the middle east was the original location of domestication. What also showed up in this report was evidence for either a second Asian domestication or a later admixture with Chinese wolves.

Dog History: When Were Dogs Domesticated?

It seems clear that dog domestication was a long process, which started far longer ago than was believed even as recently as 2008. Based on evidence from Goyet Cave in Belgium, Chauvet cave in France, and Predmosti in Czech Republic, the dog domestication process probably began as long ago as 35,000 years, although the oldest evidence for a broader relationship, a working relationship, is at the Bonn-Oberkassel site, 14,000 years ago. The story of dog domestication is still in transition itself.
Evidence for the appearance of breed variation is found in several European Upper Paleolithic sites. Medium-sized dogs (with wither heights between 45-60 cm) have been identified in Natufian sites in the Near East (Tell Mureybet in Syria, Hayonim Terrace and Ein Mallaha in Israel, and Pelagawra Cave in Iraq) dated to ~15,500-11,000 cal BP). Medium to large dogs (wither heights above 60 cm) have been identified in Germany (Kniegrotte), Russia (Eliseevichi I) and Ukraine (Mezin), ~17,000-13,000 cal BP). Small dogs (wither heights under 45 cm) have been identified in Germany (Oberkassel, Teufelsbrucke and Oelknitz), Switzerland (Hauterive-Champreveyres), France (Saint-Thibaud-de-Couz, Pont d'Ambon) and Spain (Erralia) between ~15,000-12,300 cal BP. See Pionnier-Capitan et al for more information.

Modern Breeds and Ancient Origins

A recent study of pieces of DNA called SNPs (single-nucleotide polymorphism) which have been identified as markers for modern dog breeds published in 2012 (Larson et al) comes to some surprising conclusions: that despite the clear evidence for marked size differentiation in very early dogs (e.g., small, medium and large dogs found at Svaerdborg), this has nothing to do with current dog breeds. The oldest modern dog breeds are no more than 500 years old, and most date only from ~150 years ago.

That's one contemporary view of the dog scene. If you think about the oldest paintings and weavings in museums, there were almost always dogs depicted in the art. The kings and royalty always had wonderful dogs around, different breeds typifying different countries. In modern times, you can't think of Queen Elizabeth 11 without the Corgis, and so on. But what strikes me lately is that we are once again, in some countries, anthropomorphizing dogs. Is that the right word? I mean making them into humans in our minds and actions. I am guilty of this. My sister Sarah and I had actual, almost sane sounding conversations, about how much Ralphie (the dog) enjoyed talking to me on the phone. No kidding. I daily hear people tell me what their dogs thinks. Or, "he's saying 'thank you.'" Huh?

So, lots of questions come up in my mind. Are we craaazy? Have dogs evolved so much? Are they actually better than most people? Are we lacking the ability to help people, animals are so much more grateful? How long would it take for a dog to revert to a wolf? Do we have an historical memory of when we needed dogs for protection?  Do we need that more and more again? What's with the pitbull epidemic? Are dogs better than people. Does it cost less to have a dog in suburban USA than to send a kid to college? So many questions.

Just thinking about this today as I am currently living in a house with three dogs and they are indeed a center of attention.

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