Fans of the HBO series "Game of Thrones" (2011-present) are well acquainted with the dire wolf pups that are adopted at birth by the Stark boys. These pups grow into fearsome beasts that follow and protect their masters diligently. In reality, domesticating a wolf is much more difficult and dangerous. A pup from the modern grey wolf will still grow to become a wild animal, the result of thousands of years of natural selection shaping these canids into cooperative hunters. So, how did the synergy between mankind and wolves yield the dogs of today?
By and large, the relationship between Homo sapiens and wolves has been strongly adversarial. From the start, early humans competed for the same wild prey. The aggressive nature of both species also meant that this competition was tolerated by neither. Faced with a serious threat to their safety, prehistoric humans usually eradicated wolves wherever they went. Therefore, the expectation is that the wolf should have been driven to extinction long before any dogs had the chance to arise. Symbiotic relationships, however, were also at play.
There are several theories as to how the man and wolf shifted to being side by side as opposed to looking at each other from the opposite ends of a spear. One of these ideas explores cooperative hunting between wolves and humans. This is hard to back up, however, because a wolf pack of 10 is expensive to keep, as it consumes the equivalent of an entire deer in a single day. Man would have been better by killing these inferior competitors and taking the entire quarry for himself.
A more widely accepted theory states that wolves simply began hanging out around human campsites' trash piles. There, they could rummage in the scraps if they were less aggressive and tolerated by people. The scavenger wolf hypothesis is supported by genetic data pointing to the fact that dogs can break down starches that would be present in human trash heaps, but normally absent in the wolf diet. Their ancestors who would have had a copy of the genes coding for enzymes that enable this would have been more successful in this symbiosis than purely carnivorous wolves following a camp.
The remainder of domestication is thought to be a result of how dogs socially interact with humans. Do they attack? Do they cower in fear? Are they curious and friendly when encountering people? These questions were used in an experiment conducted in the 1950s, not with dogs, but with another canid, the Siberian fox. By selecting animals that did not flee or attack people and breeding them, Russian scientist Dmitry Belyaev successfully domesticated these animals. The process took a few decades, but by the end, the tamed foxes even barked and wagged their tails unlike their wild counterparts.
So where did wolves become dogs? It's hard to say. Several other genetics studies, however, have compared present day dogs to wolf populations around the world. The most recent of these studies - carried out by Olaf Thalmann, a geneticist from the University of Turku in Finland, and Robert Wayne of the University of California, Los Angeles - indicates that dogs are not related to any currently extant species of wolf. Their common ancestor is one present only in fossils found in Europe that date back to around 20,000 to 30,000 years. A rather long domestication process indeed, this makes dogs one of the first animals to be tamed by humans.
Were these ancestors anything like modern dog breeds? Likely not. The explosion in variety and characteristics occurred during the Victorian Era, when the newly rich bourgeois bred dogs to show off their status and wealth.
PetarTodorov is a senior who is majoring in chemistry. He can be reached at Petar.Todorov@tufts.edu.
