Natural History

For really long time, the mystery of human bipedalism vexed us. Our closest relatives, the chimpanzees and the bonobos, are all knuckle-walking apes, and there was an assumption that the common ancestor of all three species was a knuckle-walker. At some point, the lineage that led to our species rose up on its hind legs, perhaps to make it easier to gaze over tall grass, and we became bipedal.

The current thinking, though, is that humans never derived from any knuckle-walking ape. Instead, the common ancestor of humans, chimps, and bonobos was likely a brachiator.  The modern brachiators are the gibbons and siamangs, the so-called “lesser apes.” These animals are highly arboreal, and because they lack tails, they rely upon their long limbs to move swiftly through the trees. When on the ground, brachiators walk bipedally, swinging their long arms to the side for balance.

Humans evolved bipedalism from these brachiators, while the chimps and bonobos became knuckle-walkers. In this scenario, humans never were knuckle-walkers, and it is misleading to think that humans rose up on our hind-legs from creatures that moved like chimpanzees.

What does this have to do with dogs?

Well, there have been quite a few studies that have compared dogs and wolves that have been imprinted on humans from an early age in hopes that we might figure out the domestication process from studying how tamed wolves behave when compared to domestic dogs.

These are interesting studies, but I think they oversell what they can answer.

It should be of no secret that I am very much a skeptic of the Raymond Coppinger model of dog domestication. His model contends that dogs necessarily evolved from scavenging wolves that gradually evolved not to fear people and then became village dogs. Our specialized breeds are thus derived from village dogs that were later selectively bred.

Coppinger thought that wolves were just too hard to domestic without this scavenger-to-village dog step that lies between truly wild wolves and their evolution to domestic dogs.

Modern wolves are hard to tame. They must be bottle-raised from an insanely early age.  Coppinger thought that it would be impossible for people living during the Pleistocene to provide that kind of care for young wolf pups.

Like the people who assumed that humans evolved from knuckle-walkers, Coppinger assumed that wolves that exist today are good models for what wolves were like during the Pleistocene. These wolves are reactive and nervous to the point of being paranoid. It is well-known that many wolves won’t even attempt to den near human settlements, and if they catch wind of humans, they soon leave.

These animals would not be easily tamed by anyone, much less people living with Stone Age hunter-gatherer technology.

I generally accepted his arguments, and in the early days of this site, I largely parroted them.

A few years ago, I was watching a documentary about the tigers of the Sundarbans, a vast mangrove forest that straddles the border between India and Bangladesh. These tigers are notorious for their man-eating behavior, and there have been many theories posited about why these tigers so readily hunt man. Among these is the argument that the Sundarbans tigers drink so much salt in their water intake that it destroys their kidneys, which disables them and makes them more likely to hunt man.

But the documentary contended that the real reason these tigers are more likely to hunt man is that all other tigers descend from populations where humans have hunted them heavily. In British India, tiger hunting was a popular activity among the colonial administrators, and this intensive hunting cause tiger populations to drop.  This hunting left behind only tigers that had some genetic basis to fear man more, and thus, man-eating tigers are exceedinlg rare now.

The Sundarbans never received this hunting pressure, so the tigers left behind had the same innate tendencies to hunt humans that the ancestral tiger population possessed.

I found this argument utterly intriguing, and I began to weigh it against what I knew about wolves. Wolves across their range have experienced even more persecution than tigers have.  In North America, we have four hundred years of humans coming up with more and more creative ways to kill them. In Eurasia, this persecution has gone on for thousands of years.

The persecution of wolves surely has had some effect in how wolves behave, including their innate tendency to accept humans and other novel stimuli in their environment.

Wolves are often so fearful that they won’t cross roads.  They just avoid people at all costs, and it just seems that this is an animal that we couldn’t possibly domesticate or even habituate to our presence.

This has led some people to suggest that dogs aren’t derived from wolves, but some Canis x creature that is related to dogs and wolves, but it is ancestral to the former but not the latter.

Genome comparisons have shown that such claims really don’t work. Dogs are derived from an archaic wolf population, and in this way, they are sort of genetic living fossils, holding the genomes of a Pleistocene wolves that no longer exist. But these wolves that became dogs were still part of Canis lupus, and thus, we have to maintain dogs as part of Canis lupus as well in order to retain the monophyly of the species.

Except for dogs that have modern wolf ancestry, no dog is actually derived from a wolf population that exists today.

And the wolf populations that exist today just seem so hard to tame and work with that it makes sense then to consider the need for Coppinger’s scavenging wolf-to-village dog stage between wild wolves and modern dogs.

The thing is, these studies using modern wolves are only using wolves that are derived from these heavily persecuted populations, and it is very unlikely that these animals are representative of the wolves that lived during the Pleistocene.

We know that when wild dogs have never experienced human hunting, they are intensely curious about us. Timothy Treadwell had a pack of tame red foxes that followed him around like dogs while he was off communing with the brown bears. Darwin killed the fox that was named after him by sneaking up on one and hitting it with a geological hammer.

Lewis and Clark came onto the American prairies where there were vast hordes of wolves lying about.  The wolves had no fear of people, and one wolf was actually killed when it was enticed in with meat and speared in the head with a spontoon.

After these wolves experienced the persecution of Western man, the only wolves left in the populations were those that were extremely wary and nervous.

In fact, the only wolves that exist now that have never experienced widespread persecution by man are the white wolves that live in the Canadian High Arctic.

I’ve had the pleasure of watching two documentaries about these wolves. The first was by Jim Brandenburg.  Brandenburg and L. David Mech spent a summer living with and filming wolves on Ellesmere.  These wolves showed no fear of them, and they allowed them to observe their natural behavior in the wild, including allowing them near their den sites.

Virtually the same documentary was recently made by Gordon Buchanan of the BBC. Buchanan came to Ellesmere and became accepted by a wolf pack, which eventually trusted him enough to allow him to babysit their pups while the adults hunted.

These wolves hunt arctic hare and muskox. They live hard lives, but because they have no real history with man, they are oddly curious and trusting of people.

It seems to me that these wolves are much more like those described by Lewis and Clark, and they are likely to have behaved much like the ancient Pleistocene wolves did. They had never undergone extensive persecution by man, and thus, they were probably quite curious about man.

If these ancient wolves were more like the Ellesmere wolves, then it seems domestication would have been a pretty easy process. In fact, it appears to me that it is so easy to have happened that the struggle would have been preventing it from happening in the first place.

So if these High Arctic wolves are a better model for the ancient wolves that led to dogs, why aren’t they included in the studies?

Well, these wolves are hard to access, and what is more, because they represent such a special population, it might not be wise to remove any of these wolves from the wild.

So the socialized and imprinted wolf pup studies really can’t be performed on them.

But we could still get DNA samples from them and compare their behavior-linked genes to those of dogs and wolves from persecuted populations.

All these other studies are ever going to do is tell you the difference between dogs and certain wolves from persecuted populations. They aren’t really going to tell you the full story of why dogs came to behave differently from wolves.

So for the sake of science, we need to understand that evolution through artificial selection has affected wolves as well as dogs. Dogs have been bred to be close to man. Wolves have been selected through our persecution to be extremely fearful and reactive.

So as interesting as these studies are, they have a big limitation, and the assumption that these wolves represent what ancient wolves were like is major methodological problem.