Researchers in Hungary have some news about dogs that probably won’t be a surprise to many. Apparently, their brains are smaller than their wild wolf ancestors, and this is down to human choices.
Well, naturally. Humans domesticated dogs from the ancestral population of wild wolves. The prevailing theory says that individual wolves who were less aggressive and more willing to socialize with humans were eventually kept as pets and bred by people. Over time, humans bred dogs (like all other creatures bred by people) to have traits that were most prized, including a friendly disposition toward their owners.
The result of thousands of years of artificial selection (that is, human breeding decisions) has resulted in an explosion of dog breeds, some of which, like the famous teacup-sized Chihuahua, bear almost no resemblance to their wild forbearers.
The Hungarian study from the Institute of Ecology and Botany, Centre for Ecological Research, Hungary, which was published in the journal Biology Letters, says modern dogs have smaller brains than ancestral wolves because of the comfortable lifestyle pet dogs enjoy. Since they are cared for and fed by humans, there is no evolutionary pressure to continue forming large brains, which are enormously “expensive” in terms of the calories they require.
The study authors don’t say exactly what specific factors have led to the brain-size decrease in dogs, they agree that it’s largely owing to human breeding choices. But there is also evidence that wild dogs undomesticated by humans have seen a decrease in brain volume over time. The investigators hypothesize that this may be partially explained by breeds that have adopted hibernation as a viable strategy.
The research team wrote that modern dogs are the domesticated descendants of the grey wolf, and that modern dogs started diverging from that population at least 15,000 years ago. “Over 400 breeds of dogs exist today,” they wrote, and nearly all of them show a small relative brain size that what’s found in grey wolves.
Dogs that live with people simply don’t need the brain power that a wild creature does. Animals living in the wild have to find or kill their own food, effectively avoid predators, and seek out a mate. None of the pressures exist for man’s best friend, who often prefers to curl up on the couch with a person.
