We, as humans, have to keep changing our definition of what makes us human. For example, we used to claim that one way we are differentiated from other animals is through our use of tools. Until we discovered that some other species do use tools. The more we learn, the more we discover we share a lot more with other species than we used to think. So what does differentiate us from other animals?

I recently read Pat Shipman’s book The Animal Connection: A New Perspective on What Makes Us Human. Ms. Shipman is a paleoanthropologist who hypothesizes: “that our connection to animals is ancient and fundamentally important because it drove humans to our three great behavioral advances: the making of stone tools; the origin of language and symbolism; and the domestication of animals.”

This book is primarily about human evolution and how our connection with animals has shaped who we are today as a species. Since dogs were domesticated long before any other animals, the domestication of dogs figures heavily into this book, which is what caught my interest. Ms. Shipman suggests that humans are genetically disposed to a connection with other species, something that is not commonly seen in any other species. We might see occasional stories of two animals of different species becoming “friends” but nothing that compares to the propensity among various human cultures for keeping “pets” of various species. Anthropologists find this in most cultures throughout the world.

According to Shipman:

“If being connected to animals is a genetically based behavior typical of humans, then there ought to be observable benefits to being with animals – and there are. . . Pets. . . fulfill a need in our lives. . . Pet owning individuals have better health, more social contacts, more exercise, and a better outlook on life than non-pet owners. Simply being with a pet lowers the heart rate, lowers cholesterol, and lowers anxiety in most people. Being with pets also raises oxytocin levels, the hormone that is key in bonding with our own infants and our mates. Increased oxytocin levels produce a feeling of calm and peacefulness, and heighten our sensitivity to nonverbal communication. Meg Daley Olmert, in her book Made For Each Other, suggests that oxytocin was the ‘main biological ingredient’ underlying animal domestication and our affection for animals.”

Ms. Shipman certainly gives us something to think about. I think I will ponder it while I snuggle with my dogs.