Inside of a Dog_ What Dogs See, Smell, and Know - Alexandra Horowitz [89]
Even so, there are other dog behaviors suggestive of their self-knowledge. In most actions, dogs do not grossly misestimate their abilities. They surprise themselves by jumping into water after ducks—only to find that they are natural swimmers. They surprise us by leaping to scale a fence—which they may in fact be able to clear. On the other hand, one regularly hears that dogs don't know a very basic fact about themselves: how big they are. Small dogs strut up to enormous dogs: their owners proclaim that their dogs "think they're big." Some big-dog owners who endure lap sitting likewise assert that their dogs "think they're small." In both cases, the dogs' accompanying behaviors lend more credibility to the notion that they do know their sizes: the small dog is compensating for his small size by trumpeting his other qualities extra loudly; the large dog raised with a lap to sit on continues with this close contact just as long as he is tolerated, and then finds a large-dog-sized pillow to sit on elsewhere.
Both small and large dog are tacitly acknowledging an understanding of their own size. It might seem unlikely that this means they are thinking about the categories big or small. But look at how they act on objects in the world. Some dogs will attempt to pick up a felled tree, but most dogs with stick-carrying habits will choose similarly sized sticks at every opportunity, as though they have gauged what can be picked up and held in their mouths. From then on, all sticks in the path of a searching dog are quickly assessed: too big? too thick? not thick enough?
Further suggestive evidence that dogs know their size comes from their rough-and-tumble play. One of the most characteristic features of dog play is that socialized dogs can, by and large, play with almost any other socialized dog. This includes the pug who leaps onto the hocks of the mastiff, reaching his knee. As we've seen, big dogs know how to, and often do, moderate the force of their play to smaller playmates. They can withhold their fiercest bites, jump halfheartedly, bump into their more fragile playmates more gently. They might willingly expose themselves to attack. Some of the largest dogs regularly flop themselves on the ground, revealing their bellies for their smaller playmates to maul for a while—what I called a self-takedown. Older, learned dogs adjust their play styles to puppies, who don't yet know the rules of play.
Play between dogs of mismatched statures often does not last long, but it is usually an owner, not a dog, who moves to stop it. Most socialized dogs are considerably better at reading each other's intent and abilities than we are. They settle most misunderstandings before owners even see them. It's not the size or the breed that matters; it's the way they talk to each other.
Working dogs provide another glimpse into what dogs know about themselves. Sheepdogs, raised from their first weeks of life with sheep, do not grow up to act like sheep. They do not bleat or scream, chew their cud, aggressively head-butt, nor suckle from the ewe, as sheep do. Their cohabitation leads dogs to interact socially with sheep—using social behaviors characteristic of dogs. Those who study sheepdogs observe, for instance, that dogs will growl at sheep. Growling is a dog communication: the dog is treating the sheep more like a dog than like a possible meal. These dogs' only fault is to overgeneralize: not only are they clear on their own identity, in some sense—they also think that everyone else is a dog, too. One could call this foible very human: they talk to sheep as though they were dogs, just as we talk to dogs as though they were humans.
Between play bouts, stick-retrieving,