Jerry Coyne points to the extreme changes made possible by artificial breeding of dogs within the last 150 years: "Dog breeding: the debasement of the American cocker spaniel". One can look at the situation as an ecological change: former working dogs are now selected for their appearance much more than for their ability to do their former jobs. WIth attendant side effects.
Love your blog, which I stumbled across while googling for more detail on the wolf tracks in Chauvet Cave. Have been fascinated by this stuff since 1st grade, did fieldwork in high school & college, and now wish I hadn't let the dryness of academia drive me away from anthro back in Ann Arbor (not Wolpoff's fault). I still read around though; loved your take on the Clovis Comet Crap (what suckers the media are), though obviously impact events play a major evolutionary role.So anyhow, back to my question. Recently saw Herzog's documentary on the art in Chauvet. Having dabbled in caving during a Peace Corps Guatemala stint, I find it extremely unlikely that a wolf is going to be walking around deep in a pitch black cave by himself. To me this is potentially strong evidence if not downright proof of domestication, but I'm looking for more specifics on track layout (esp. in relation to those human child tracks) and actual location/depth within the cave (to ascertain feasibility of wild vs domesticated access). Do you have anything more on this, or could you point me towards same? Much obliged, tlc
Thanks for the kind words!
Pat Shipman has written about this topic quite a lot lately, she has a book out on the history of human-animal interactions. Last year she wrote about Aurignacian-era dog domestication evidence (I linked here):
http://johnhawks.net/weblog/reviews/archaeology/upper/europe/dog-domesti...
And I cited some of the original research here:
http://johnhawks.net/node/1686
The main impediment to accepting a very early domestication is the genetics; as modern dog breeds don't seem to have such a distant ancestor. But that may be due to recent gene flow among breeds and subsequent selection after domestication. At the very least, domestication was clearly early enough that dogs accompanied people to the Americas before 12,000 years ago.
Razib's post on the genetics of canids ("A map of charismatic canid genomic variation") does a nice summary of a recent paper in Genome Research, by vonHoldt and colleagues [1]. I just want to quickly point out that humans are not the only species for whom we are developing a complicated and relatively well-resolved scenario of population history. Still, the methods used in present-day studies of population structure are really "first-cut" kinds of approaches. The data have reached the point where simple models no longer fit, and that's a good thing.
Also, there's this:
Another interesting implication of the possibility of long term hybridization is that some of the distinctive alleles of extinct American wolf populations may now only be found in coyotes, since this species was much better at surviving human encroachment. And if wolves went extinct tomorrow, we could reconstruct them from what we find within coyotes I’d think.
That gives me the chance to pull out my favorite quote from the famous evolutionary plant biologist G. Ledyard Stebbins [2]:
We inevitably reach the conclusion, therefore, that introgressive genotypes not only persist indefinitely, but that also, like polyploids, they can migrate far beyond the areas in which they originated, and can actually survive after the non-introgressed parental species has become extinct.
Theories that predict unknown facts before they can be observed are like uncut diamonds.
Here's a quote you don't see every day:
"It just so happens this person who lived 9,400 years ago was eating dog," Belknap said.
Amazing what they can do with coprolites nowadays.
Sorry to interrupt the 'all Anthropoid all the time' theme going on lately but I want to get back to a subject we've discussed before (well kind of).
Coyotes have a record in recent years of attacking and even killing people. Why do we see so few reports of wolves attacking and killing people? Seemingly it would be much easier for them. The 'yotes that killed the girl in Canada went after a full sized adult.
Perhaps a pack of wolves would leave less evidence?
I think first you have to correct for the fact that coyotes are around people a lot more. People who have gone places where they are likely to encounter wolves tend to be better prepared outdoorsmen, able to deal with bears.
But maybe in addition to that, there's a pack hunting advantage. Coyotes hunt independently or in small groups and are apt to be both hungrier and more limited in range due to conflicts with neighbors. Wolves get their risk spread among more group members and maintain larger home ranges.
I think leopards are also more dangerous to people than lions, may be the same reason.
I didn't see this article when it came out but I ran across it this week: Pat Shipman writes about possible evidence for early dog domestication ("The Woof at the Door").
Some of the earliest known art objects from Europe include the remarkable cave paintings of Chauvet Cave in France, the oldest of which were made 32,900 ± 490 years ago. None of the hundreds of glorious Chauvet paintings show wolves. However, the cave preserves something even more haunting: the footprints of a human child about four-and-a-half feet tall, as well as many footprints of large canids and bears.
Michel-Alain Garcia of the Centre National de la Recherche Scientifique in Nanterre noticed in 1999 that one track of canid prints appears to accompany the child’s prints. These canid prints, unlike the others, have a shortened middle digit on the front paw: a characteristic of dogs. Garcia suggested that the child and dog might have explored the cave together. Charcoal from a torch the child carried is 26,000 years old.
It's a nice article throughout, describing why some are convinced that dog domestication was Aurignacian or earlier in time. It would be interesting to see an update to the story in light of the recent description of dog and wolf genetics, that argued for a more recent domestication in the Near East. Personally I don't see a contradiction here, if we suppose that the population of dogs may have grown enormously with pastoralism in the Near East, drawing substantially upon local wolf populations. It's shaping up to be a complicated problem.
Another case of large mammal evolution by introgressive hybridization:
Coyote + wolf = new breed of predator
New DNA evidence reveals that coyotes have bred with wolves in the the northeastern United States, turning mice-eating coyotes into much larger animals with a hunger for big prey, such as deer.
The linked article describes a study by Roland Kays and others, who went looking at the mtDNA of nearly 700 museum coyotes and donated specimens, looking for wolf. When they found it, they were able to correlate skeletal measurements with wolf ancestry and trace the progress of the wolf introgression from somewhere "north of the Great Lakes".
They hit on some essential points:
"This is an evolutionary mechanism to generate new variation that can work faster than genetic mutation," added Kays, curator of mammals at the New York State Museum.
If there's a niche for a more solitary canid predator, larger and more aggressive than coyotes, bringing in wolf genes may be the fastest way to get there.
This is a dynamic system, caught in mid-transition. The coywolves have not reached any stable equilibrium distribution with coyotes, and the wolf chromosomes have not broken up within the coywolf descendants to allow the dissociation of adaptive from maladaptive wolf genes in the hybrid population. Over the long term, the wolf mtDNA might be lost entirely, if there are any negative epistases between wolf mitochondrial genes and the mostly nuclear coyote genes that interact with them. Assessment of hybridity by mtDNA is conservative (misses hybrids with paternal instead of maternal origin) and temporary (the purely maternal lineage may disappear over evolutionary time due to slightly negative epistasis).
Other: "Adaptive introgression of coat color in wolves"
UPDATE (2009-09-24): See also in the mailbag.
Time magazine has a nice article by Carl Zimmer, which profiles anthropologist Brian Hare, who's been busy studying dogs:
Hare suspects that the evolutionary pressures that turned suspicious wolves into outgoing dogs were similar to the ones that turned combative apes into cooperative humans. "Humans are unique. But how did that uniqueness evolve?" asks Hare. "That's where dogs are important."
One complaint: I don't see how Time expects anybody to read their articles online, when they are followed with gratuitous (and at best, marginally related) "CLICK HERE" ads. This one is a howler:
Henry, as Kivell affectionately admits, may not be "the sharpest knife in the drawer," but compared to other animals, he's a true scholar. See TIME's photoessay "Color My Dog!"
Lots of interesting stuff, though, if you're into dogs -- maybe you can sign up to become one of "thousands" of research volunteers...
Jennifer Viegas writes about dogs as a model for human social evolution.
"The dog has come into its own as a great new model for understanding the mind in general, and the evolution of the human mind in particular," [Marc] Hauser told Discovery News. "Not only have we lived with dogs for thousands of years, but because of this relationship, we have acted as an agent of selection to modify aspects of their behavior and minds."
For the past couple of thousand years, maybe more, our selection on dogs has been both intentional and unintentional. Before that, as dogs were first becoming commensal with human societies -- more than 20,000 years ago -- the essential changes in dog social behavior were the natural effect of human social systems.
If we were generating all that selection on them, imagine how much we were imposing on each other.
Mark Derr of the NY Times reports on a new study showing that black North American wolves got their melanism from dogs:
In a bit of genetic sleuthing, a team of researchers has determined that black wolves and coyotes in North America got their distinctive color from dogs that carried a gene mutation to the New World.
The finding presents a rare instance in which a genetic mutation from a domesticated animal has benefited wild animals by enriching their “genetic legacy,” the scientists write in Thursday’s Science Express, the online edition of the journal Science. Since black wolves are more common in forested areas than on the tundra, the researchers concluded that melanism — the pigmentation that came from the mutation — must give those animals an adaptive advantage.
There are so many examples of this phenomenon in mammals now! This one is interesting because it would have been carried in by early dogs brought in via Beringia -- so it's another case where an intercontinental migration has brought a new adaptive allele that introgressed into a natural population.
There is also a date:
Comparing large sections of wolf, dog and coyote genomes, Dr. Barsh and his colleagues concluded that the mutation arose in dogs 12,779 to 121,182 years ago, with a preferred date of 46,886 years ago. Since the first domesticated dogs are estimated to date back just 15,000 to 40,000 years ago in East Asia, the researchers said that they could not determine with certainty whether the mutation arose first in wolves that predate that time, or in dogs at an early date in their domestication.
This could have been selected in the very earliest domesticated dogs, based on that date. It would be useful to have a number of genomes from ancient wolves to screen against variation present in the wild population around the time of domestication.
The really cool thing is that we will probably have samples like that within the next several years...
