The dog: symbiote or parasite?

I've long thought of the Dog as a brilliantly successful cuckoo-like brood parasite. This only increases my admiration for the species. One can do much worse than develop a remora-like attachment to the most dangerous and dominant large predator the planet has ever known. (Ok, so our reign will be short. Not every species can be a shark.)

A biologist friend, however, scoffs at this. He claims the dog is obviously a symbiote. Well, to be honest, I know the boundary between symbiote and parasite is fungible. Dogs are great at cleaning up rotting meat, which probably has some health advantages. They may help geek-drones and women survive around alpha-males -- though they are prone to run away in a fight (they're not stupid). I'm sure they have other advantages ...

Whatever. We've been together long enough that we've probably altered each other's evolution. Jon Katz, another dog lover, weighs in on the debate:

The real reason we love dogs. - By Jon Katz - Slate Magazine

... Archer suggests, "consider the possibility that pets are, in evolutionary terms, manipulating human responses, that they are the equivalent of social parasites." Social parasites inject themselves into the social systems of other species and thrive there. Dogs are masters at that. They show a range of emotions—love, anxiety, curiosity—and thus trick us into thinking they possess the full range of human feelings.

They dance with joy when we come home, put their heads on our knees and stare longingly into our eyes. Ah, we think, at last, the love and loyalty we so richly deserve and so rarely receive. Over thousands of years of living with humans, dogs have become wily and transfixing sidekicks with the particularly appealing characteristic of being unable to speak. We are therefore free to fill in the blanks with what we need to hear. (What the dog may really be telling us, much of the time, is, "Feed me.")

As Archer dryly puts it, "Continuing features of the interaction with the pet prove satisfying for the owner."

It's a good deal for the pets, too, since we respond by spending lavishly on organic treats and high-quality health care.

Psychologist Brian Hare of Harvard has also studied the human-animal bond and reports that dogs are astonishingly skilled at reading humans' patterns of social behavior, especially behaviors related to food and care. They figure out our moods and what makes us happy, what moves us. Then they act accordingly, and we tell ourselves that they're crazy about us.

"It appears that dogs have evolved specialized skills for reading human social and communicative behavior," Hare concludes, which is why dogs live so much better than moles.

These are interesting theories. Raccoons and squirrels don't show recognizable human emotions, nor do they trigger our nurturing ("She's my baby") impulses. So, they don't (usually) move into our houses, get their photos taken with Santa, or even get names. Thousands of rescue workers aren't standing by to move them lovingly from one home to another.

If the dog's love is just an evolutionary trick, does that diminish it? I don't think so. Dogs have figured out how to insinuate themselves into human society in ways that benefit us both. We get affection and attention. They get the same, plus food, shelter, and protection. To grasp this exchange doesn't trivialize our love, it explains it.

I'm enveloped by dog love, myself. Izzy, a border collie who spent the first four years of his life running along a small square of fencing on a nearby farm, is lying under my desk at the moment, his head resting on my boot.

Rose, my working dog, is curled into a tight ball in the crate to my left. Emma, the newcomer who spent six years inside the same fence as Izzy, prefers the newly re-upholstered antique chair. Plagued with health problems, she likes to be near the wood stove in the winter.

When I stir to make tea, answer the door, or stretch my legs, all three dogs move with me. I see them peering out from behind the kitchen table or pantry door, awaiting instructions, as border collies do. If I return to the computer, they resume their previous positions, with stealth and agility. If I analyzed it coldly, I would admit that they're probably alert to see if an outdoor romp is in the offing, or some sheepherding, or some beef jerky. But I'd rather think they can't bear to let me out of their sight.

And the answer is ... symbiote. I happen to believe, with a bit of evidence, that humans have almost uniquely flaky brains (Temple Grandin mentions this in one of her books as well). We have lots of very significant relatively recent evolutionary hacks in our wetware, and we know that hacks produce bugginess and instability. We have a high rate of major and minor defects -- as near as we can tell we're much worse off than any other animal. It's the price we've paid for sentience. A social animal with a buggy brain has a major need for psychic support. The dog is a first-rate psychic crutch. That's a heck of a value proposition. All hail the Dog!