Inside of a Dog_ What Dogs See, Smell, and Know - Alexandra Horowitz [106]
This kind of behavior may seem unsurprising. After all, we humans spend much time trying to pair-bond, maintaining or discussing our current pair bonds, or trying to extricate ourselves from ill-advised pair bonds gone sour. But from an evolutionary point of view, bonding with others is non-obvious. The goal of our genes is to reproduce themselves: an inherently selfish aim, as sociobiologists observe. Why bother with others at all? The explanation of a selfish gene bothering to mind and greet other gene forms turns out to also be selfish: sexual reproduction increases the chance of helpful mutations. It also behooves the selfish gene to ensure that one's sexual mate is healthy enough to bear and raise the new, infant genes.
Sound far-fetched? A biological mechanism has been discovered that supports pair-bonding. Two hormones, oxytocin and vasopressin (known for their roles in, respectively, reproduction and body-water regulation), are released when interacting with one's partner. These hormones make changes at the neuronal level, in areas of the brain involved in pleasure and reward. The neural change results in a behavioral change: encouraging association with one's mate, because it simply feels good. In the small, mouselike prairie voles that the researchers studied, the vasopressin seems to work on dopamine systems, which results in the male vole being very solicitous of his mate. As a result, prairie voles are monogamous, forming long-lasting pair bonds, in which both parents are involved in raising the wee voles.
But these are intraspecific pair bonds: between members of the same species. What started cross-species bonding, which now results in our living with, sleeping with, and dressing up in sweaters our dogs? Konrad Lorenz was the first to describe it. He gave a description of what he called simply "the bond" in the 1960s, well before the current age of neural science, and before human-pet relationship seminars. In scientific language, he defined the bond as revealed in "behaviour patterns of an objectively demonstrable mutual attachment." In other words, he redefined the bond between animals not by its goal—such as mating—but by the process—such as cohabitating and greeting. The goal could be to mate, but it could also be survival, work, empathy, or pleasure.
This refocus opens the door to considering lots of other, non-mating kinds of pairings as true bonds—between members of the same species, or between two species. Among dogs, working dogs are a classic case. For instance, sheepdogs bond early in life with the intended subject of their work: sheep. In fact, to be effective herders, sheepdogs must bond with sheep in their first few months. They live among the sheep, eat when the sheep eat, and sleep where the sheep sleep. Their brains are in the throes of rapid development at an early age; if they don't meet sheep then, they don't become good shepherds. All wolves and dogs, working or not, have sensitive periods of social development. Early in puppyhood they show a preference for the caregiver, seeking her out and responding to her differently than to others, with a special greeting.* For young animals, it is adaptive to do so.
There's still a big leap, though, between a bond wrought of developmental advantage and one based in companionship. Given that humans neither mate with dogs nor need them to survive, why might we bond?
BONDABLES
The feeling of mutual responsiveness: that each time one of us approached or looked at the other, it changed us—it effected some response. I smiled to see her look or wander over; her tail would thump and I could see the slight muscle movements of the ears and eyes that indicated attention and pleasure.
We don't need to be herded; neither are we born to herd. Nor, as we saw earlier, are we a natural pack. What, then, accounts for our bond with dogs? There are a number of characteristics of dogs that make them good candidates for us to