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Dogs are easy to take for granted. To wit, our poor family dog, once the cherished pseudo-child brought on woodland hikes and fed organic treats, has been getting accidentally sat on an awful lot lately, as she snoozes on the couch waiting for someone to pay attention to her. Her habit of french-kissing our guests aside, she's a great companion. But why? As my daughter noticed the other day, "She has really sharp teeth!" (This, as she absent-mindedly fished her hand around the old dog's stinking mouth.) So why doesn't she take her canine revenge and eat us in our sleep?

According to naturalist Mark Derr, there's no real consensus on how exactly dogs evolved from wolves. As he told NPR,  Derr himself believes that humans and wolves developed a close relationship after recognizing themselves in each other while hunting on the trail of big game. "[That's when] they started traveling together, and they've been at it ever since," he says. "The dog is a creation of wolves and humans—of two equal beings that came together at a certain point in history and have been together ever since." Of the special love between humans and dogs, Derr said, "I call it a 'deep empathy' between these two species that resonates with each other in a way that makes them comprehensible to each other, even though they don't speak the same language." (Read or listen to the whole piece for Derr's insights on small dogs, special breeds, and the cultural evolution of dogs.)

Two equal beings—that's pretty much what my dog thinks, too. As for the deep empathy, I admit I don't always feel that as I'm tugging her leash away from delicious trash-piles in the park. But if I thought about how close she is to being a wild wolf, I might better appreciate our strange, wonderful, cross-species relationship.

More on dogs:
The story of Rin Tin Tin
Training a dog with love
What dogs can teach us