There is a long and fascinating thread of research about the health benefits of dogs. It turns out that the dog is a kind of wonder drug, an all-around stress reducer. Pet owners recover at a substantially faster rate from heart problems than do non–dog owners. ...

... Researchers at Azabu University in Japan found last year that the dog’s gaze at its owner increases the owner’s oxytocin level. ...

... specific canine qualities—the dog’s gaze, its unending adolescence, its uncanny responsiveness to human cues—evolved, a process that Serpell calls “anthropomorphic selection.” What was created was not, precisely, a human child, but it certainly was able to push some of the same buttons. According to one study, 84 percent of dog owners consider their animals akin to children—not a surprise, given all the baby talk. The British evolutionary psychologist John Archer has written, in critiquing Serpell’s work, that the dog’s ability to suck up human caregiving that could be going to human children while providing no evolutionary advantage makes them a social parasite. But possibly the stress-reduction effects, more than theoretical camp-guarding and hunting benefits, may have earned the dog’s keep.... —NY Magazine

"Doesn't seem to be; she's just lying there."