Since their emergence over 200,000 years ago, modern humans have established homes and communities all over the planet.
But they didn't do it alone.
Whatever corner of the globe you find homo sapiens in today, you're likely to find another species nearby: Canis lupus familiaris.
Whether they're herding, hunting, sledding, or slouching the sheer variety of domestic dogs is staggering.
But what makes the story of man's best friend so surprising is that they all evolved from a creature often seen as one of our oldest rivals: Canis lupus, or the gray wolf.
When our Paleolithic ancestors first settled Eurasia roughly 100,000 years ago, wolves were one of their main rivals at the top of the food chain.
Able to exert over 300 lbs of pressure in one bone-crushing bite and sniff out prey more than a mile away, these formidable predators didn't have much competition.
Much like human hunter-gatherers, they lived and hunted in complex social groups consisting of a few nuclear families, and used their social skills to cooperatively take down larger creatures.
Using these group tactics, they operated as effective persistence hunters, relying not on outrunning their prey, but pursuing it to the point of exhaustion.
But when pitted against the similar strengths of their invasive new neighbors, wolves found themselves at a crossroads.
