- Meat-eating and animal domestication separated humans from other apes.
- Taking in animals is uniquely human and seems counterproductive at first.
- Hunting and caring for animals drove the development of technology and languages.
Dogs, cats, cows and other domesticated animals played a key role in human evolution, according to a theory being published by paleoanthropologist Pat Shipman of Penn State University.
The uniquely human habit of taking in and employing animals -- even competitors like wolves -- spurred on human tool-making and language, which have both driven humanity's success, Shipman says.
"Wherever you go in the world, whatever ecosystem, whatever culture, people live with animals," Shipman told Discovery News.
For early humans, taking in and caring for animals would seem like a poor strategy for survival. "On the face of it, you are wasting your resources. So this is a very weird behavior," Shipman said.
But it's not so weird in the context something else humans were doing about 2.6 million years ago: switching from a mostly vegetarian diet to one rich in meat. This happened because humans invented stone hunting tools that enabled them to compete with other top predators. Quite a rapid and bizarre switch for any animal, Shipman said.