A Dog is not a Wolf
There is no doubt that the domestic dog, Canis lupus familiaris, is descended from the wolf, Canis lupis, but that doesn’t make the dog a wolf. It’s true that the dog shares the same number of chromosomes with the wolf, also with the jackal and the coyote. In fact, all four species can interbreed with one another and produce offspring.
The dog also shares around 64% of its behavioural patterns with the wolf, which although is more than any other two species share, still doesn’t make the dog a wolf ~ after all, there are 36% of behavioural patterns that remain exclusively lupine. The brain of the domestic dog is smaller than the wolf brain. Put simply, the wolf can outsmart the domestic dog any day because its brain is bigger. A bigger brain means better problem solving abilities, which is why the wolf, after humans, is the most widespread of all social predators found throughout Europe, Asia and North America, with around 38 subspecies of the Grey wolf (left), also known as the Timber or European wolf, making up the numbers.
One of these subspecies, the small Asiatic wolf (right), also called the Arabian wolf, is the most likely progenitor of many European and Asian domestic dogs. There are two possible evolutionary routes of wild, Asiatic wolf to domestic dog ~ one is artificial selection, the other is natural selection ~ but which route is most likely?
Up until the age of around 33 days, wolf (and dog) puppies are completely dependent on milk. Wolf biologist Erik Zimen found that once wolf puppies reached 19 days old, they could not be socialised to humans. Add to this the fact that even human socialised wolves are extremely difficult to tame (i.e. to get them to willingly remain in the company of humans), let alone train, and that the offspring of a ‘tamed’ wolf, unless socialised to humans before nineteen days old, will have a lifelong fear of humans and will flee from their presence, the idea that the domestic dog evolved through Mesolithic man capturing litters of pre-19-day-old wild, wolf puppies, managing to keep them alive until they were able survive on solid food, successfully raising them to adulthood, keeping them tame, and training them to be trusty hunting companions, is a very romantic notion.
I suspect that Mesolithic man probably had far more important things to do.
So artificial selection appears to be the dog’s unlikelier evolutionary route, however, there is a fantastic example of modern day, artificial selection that can be used to support the natural selection theory.
Although his experiment was with silver foxes, Russian geneticist, Dmitri Belyaev, managed to produce, in just 18 generations, foxes that behaved and looked like dogs. Belyaev hadn’t intended to produce dog-like foxes. He was actually trying to select for what he observed in about 10% of the captive bred, but none-the-less wild, fur farm silver foxes, a quiet, non-fearful, non-aggressive, exploratory reaction to people, which he and his colleague, Lyudmila Trut, believed to be inheritable. Belyaev selected from this population and bred a second generation, which indeed inherited this calm, curious temperament. His breeding programme continued but with stricter selection, until only the foxes that willingly approached him were selected for breeding. The 18th generation of foxes actively searched for, climbed on, and took food from their keepers. They could be carried around, would actively roll over and expose their bellies, and even responded to their names. They also had black and white fur, floppy ears and curled tails, made dog-like sounds, and the females came into heat twice a year (like wolves, foxes come into heat just once a year).
What Belyaev’s experiment suggests with regards to the evolution of the domestic dog is that if just a few, inherently calm and curious individuals from the widespread Asiatic wolf population chose to remain on the outskirts of Mesolithic villages and feed off human food waste rather than by hunting and scavenging elsewhere, and some of the calmest, most curious of those wolves produced offspring, through the process of natural selection, the Asiatic wolf could have evolved into a floppy eared, curly tailed dog-like creature that whined and barked and willingly followed the human villagers around.
Inherently tame, the newly-evolved dog’s strategy of life differed from that of its wolf forebears. It didn’t need to stay with its family and hunt in large packs for the best chance of survival, it just had to co-exist peacefully and stay near humans, which raises the question, is the dog a true pack animal?