The connection between humans and domesticated animals goes back millions of years and may have helped humans develop tools and even language, researchers say. The interspecies connection—nearly unique to humans and their pets and livestock—"connects the other big evolutionary leaps, including stone tools, language and domestication," a paleoanthropologist tells LiveScience. "Instead of being isolated discoveries, there's a theme here. It's very deep and very old."
The first domesticated animals weren't tamed as food sources; they were dogs, useful in hunting, in transportation—and as companions. "If you have a dog that can hunt, you don't need to turn into a fast-moving animal with sharp teeth," says the researcher. "If you're storing grains, you don't need to evolve claws and an intense focus to kill rats, (because) you have cats that do it for you." For more on evolution, which proceeds more quickly in Tibet than anywhere else on earth, click here.