Dogs can be trained to discriminate. Some Jamaican resorts feature dogs that chase blacks off the beach while leaving white frat boys to fry like bacon. South Africa's apartheid government bred "Boerbuls" by crossing Rottweilers, Dobermans, bloodhounds, German shepherds, and even wolves to create very aggressive dogs for its security services. In the 1980s, the Herstigte Nasionale Party advertised such animals as "racist watchdogs" created "especially for South African circumstances." In his 1982 film White Dog, director Sam Fuller explores the socialization of racism by having a black man attempt to retrain a dog taught to kill blacks—a so-called white dog—only to have the dog attack whites instead. Paramount found the film disturbing enough to block its release for more than a decade.
Barring human intent, however, what turns an otherwise sweet dog like Percy into a bigot? Typically, such behavior indicates that the dog was not exposed to the people it now targets during its developmentally "sensitive time"—weeks 3 through 12—when its understanding of the world was formed. "If you take a dog who has never encountered a black man, or someone who has a funny walk, who uses a walker, or has a gimp or a limp, and he sees the first one in his life when he's six months old. … it's going to be a shock," says Dodman. "He's going to think 'Jinx! That's pretty strange! What the heck is that!' They might hide—that's the more fearful type of dog. But if they're a little bit macho"—known in the trade as "fear aggressive"—"they might try and go for it, to try and drive it away. And it's because they're unfamiliar."
But even if unfamiliarity breeds contempt, how does this explain Percy? Whatever the circumstances of his early life, being abandoned in Fort Greene indicated that he was, if not raised by, at least exposed to people of color. In such a case, a dog probably has had a bad experience at the hands (or feet) of those it doesn't like. This does not necessarily incriminate Percy's previous owner. In The Dog Who Loved Too Much, Dodman profiles a dog who developed a mysterious hatred of white-bearded men late in life. Eventually Dodman determined that the owner's white-bearded ex-boyfriend, left alone with the dog just once, was the likely culprit. "A dog's memory is like a photographic plate," Dodman says, "whatever happened, it just took a snapshot of that person and logged it in its long-term memory as 'bad'." (In the same vein, dogs can develop an aversion to certain breeds, sizes, and colors of other dogs.) Extreme trauma can even cause a dog to exhibit the symptoms of post-traumatic stress disorder...
Apprehension on the human's side and ignorance on the dog's can lead to a didactic encounter that reinforces prejudice and fear on both sides. The personality of the owner can make matters even worse. Dodman recently completed a large study of the personality profiles of owners whose dogs are fear aggressive and—no surprise—the owners tend to be somewhat fearful and awkward themselves. "If you are nervous around people, the lead becomes a telephone line going straight to the dog," he says. "As you tense up on the lead, the dog will pick up on the tension. He might glance at you and see the expression on your face and then he is keyed and ready to go. Cocked and loaded."
Add race to the equation, and the potential for ugliness deepens. If a white owner is apprehensive about say, blacks, the dog could manifest that apprehension, which could encourage blacks who encounter that aggressive canine to fear dogs and dislike their white owners. Even owners like my friends, who I'll posit didn't come into the situation with prejudice, now find themselves tightening the leash or crossing the street when they see someone Percy is prone to bark at coming their way. And while they do this to avoid a bad situation, it could reinforce the very qualities they wish their dog didn't possess.