Genetics
Alternate Views on the Origins of Dogs
Challenging conventional understanding of the evolution of modern dogs.
Posted August 30, 2021 Reviewed by Davia Sills
Key points
- MRI studies of farm foxes counter expectations regarding animal brain size and domestication.
- Ancient wild wolves had mottled coats, previously thought to be a trait of domesticated dogs.
- New findings raise the questions regarding the relationship of wolves to hominins.
I have observed before that we need to be careful about making absolutist pronouncements about the abilities—physical and mental—of our distant foraging predecessors. Too often, we leap to conclusions that confirm our expectations derived from our systemic cultural biases. The best current example of this involves the Neanderthal, the supposedly lumbering, dull evolutionary failure around whom our predecessors spun a web of extinction.
Some years ago, I set out to discover what I could about Neanderthals, who appear to have had a run of about 300,000 years. At the time, most experts in the field dismissed as fantasy any suggestion that Neanderthals commanded fire or were capable of speech—forget any more sophisticated activity, like creating art or taming animals or traveling across open water. A decade later, we know that Neanderthals successfully did all these things and more, not to mention left us carrying their genes as well.
The point is that whatever we think we know now is often overturned tomorrow as new methods for extracting ancient DNA come into play in laboratories and new material is excavated.
Case in point: The brain size of domesticated animals
For example, in June, a group of researchers led by Erin Hecht, an associate professor at Harvard University, published a paper reporting on the results of the examination of MRIs of the brains of foxes in Siberia, including those born to be “tame” or domesticated; those deliberately selected for an abundance of “aggression” toward people (taken as the opposite of domestication or tameness); and those allowed to randomly breed (as much as any creature can be allowed to randomly breed in a closed colony of farm foxes).
The results of this study, if they prove out, are indeed revolutionary, for one of the major tenets of domestication theory dating back to Darwin’s day is that the brains of domesticated animals are reduced in size from those of their wild kin, the implication being that this reduction is related to intelligence and other functions. If that’s true, Hecht’s work junks about a century of theories, nearly all of which set out to prove the point that this reduced brain had a role to play in domesticated animals becoming more docile, more pliable, but also in developing the very identity that defines domestication of the mottled coat, shortened tail, floppy ears, all of which imply a lack of vigor.
I won’t go into all the details of the MRI study, but let’s say it’s true. It’s a clever piece of work, and among the specific findings was that the parts of the brain that were expected to show reductions in size in the animals bred specifically for tameness or aggression—that is, the amygdala, the cerebellum, the prefrontal cortex, and the hippocampus—did not respond as predicted. In other words, something else is at play, and that something else certainly affects whatever is going on with those foxes.
What else has happened in research that relates to these findings?
A mottled coat is one of the sure signifiers, like brain size, of domestication. It has been taken as that for years. A study, recently published in Nature Scientific Reports by Saverio Bartolini-Lucenti and colleagues, suggests that these mottled coats were, in fact, common in wolves before the modern wolf split from the dog 40,000-50,000 years ago. The team asserts that genes for variable coat color existed in ancient wolf populations as well as ancient dog populations, so mottled coats were not the result of domestication but something that the ancient wolves were born with.
![Ted/Wikimedia Commons Ted/Wikimedia Commons](https://cdn.psychologytoday.com/sites/default/files/styles/article-inline-half-caption/public/field_blog_entry_images/2021-08/african_wild_dog_4851128942.jpeg?itok=ePShNp_7)
You can see similar coats in photos or videos of African wild dogs, Lycaon pictus. These creatures are fascinating for many reasons, one of which is their broken coats, which look so much like those of dogs, and another is the fact that, unlike foxes, they have the same number of chromosomes as dogs—78. They are pack hunters of the ultimate kind, equal or superior to wolves. They engage in the cooperative raising of their young. They perform altruistically and will take care of their disabled or maimed fellow African wild dogs, whether members of their pack or not. They proceed by consensus, which is agreed upon by sneezing.
They came into Africa, it would appear, some 1.5 million years ago from East Asia and, accordingly, were initially designated by scientists as the East Asian wild dog. But they are now known to have been the most successful of the canid predators and were just about circumglobal. They were highly successful pack killers of game larger than themselves and were found all over Asia and Europe.
It turns out that these animals had some kind of intersection with ancient hominins—perhaps Homo erectus—some 1 to 2 million years ago in a cave in the Caucasus called Dmanisi. The cave is renowned as the site of the discovery of the first anatomically modern hominins passing from Africa into Asia. It is a mixing zone of the first rank among archaeological sites.
To find these hominins and wild dogs coexisting in the same space at roughly the same time suggests that they had some kind of relationship. What it was is unknown. The authors of this study suggest that it might have involved hominins scavenging the kill sites of Lycaon pictus—how is that for a reversal? Also, it might be that hominins learned things by observing the behavior of these canids—something about cooperation, consensus building, and the like.
Major takeaways
Here I call attention to Wolfgang Schleidt and Michael Shalter, who published a seminal paper in which they suggested ancient dogs may have learned from Neanderthals how to be a dog, a notion I expanded through time and geography to include Homo erectus. As we learn more about human evolution in this timeframe, we may find that other hominin species were involved in interacting with wolves and learning the fundamentals of how to live with them and, ultimately, how to take them in as dogs. There is much to go to understand how that happened, but it makes perfect sense.
What I suggest is that we humans didn’t invent things like fire or cooperation or culture: We inherited them from our animal nature, from our canid natures. We stepped into a readymade world. Animals and people were traveling all over the world and being, generally, human.