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I keep hearing pit-bull owners claim their dogs are no more dangerous than any other medium-size to large dog. It’s just bad press, they say. Are there any statistics that prove that they (the dogs, not the owners) are more dangerous or aggressive than other dogs? Maybe they are generally docile but so powerful that when they do attack they cause more damage. —Decent Dog-Fearing American

Not sure this is a distinction of importance. “Sir, my little Muffy is a docile creature who doesn’t know her own strength. Let me get a flashlight and we’ll see if we can find your arm.” So let’s skip the pit-bull owners’ rationalizations and get to the gut question: How dangerous are these dogs?

Although there’s some argument over their origin, pit bulls were probably the result of crosses between bulldogs and working terriers to produce a new type of dog for, among other uses, pit fighting—hence the name. Despite the mental image of dogs tearing each other to pieces that the name evokes, pit bulls have a long history as family watchdogs and pets. Today the term pit bull is commonly applied to three related but distinct breeds—the American Staffordshire terrier, the Staffordshire bull terrier, and the American pit bull terrier—as well as to any number of other dogs of similar appearance. An experienced breeder could undoubtedly tell all these animals apart; you or me, probably not.

Before we get into how dangerous pit bulls are, a more basic question: How dangerous are dogs? Answer: plenty. According to the Centers for Disease Control, about 4.5 million people are bitten by dogs each year, with 885,000 needing medical attention. In 2006, more than 31,000 people underwent reconstructive surgery following dog bites. Granted, you’ve got a much greater chance of being killed by lightning than by an attacking dog. But when you ask about dangerous, the comeback is: compared to what?

Enough chatter. I reviewed more than 20 technical reports on dog attacks. Some common themes:

• Identifying a biting dog’s breed is tough and often impossible. Several studies of dog attacks ended up with large numbers not assignable to a specific breed. Researchers in a 1997 Children’s Hospital of Pittsburgh study could document breed in just 47 percent of cases. Breed identification is further complicated by crosses and mixes.

• On the possibly risky assumption the breed IDs we do have are accurate, three breeds keep rising to the top of the Most Likely to Chomp list: German shepherds, rottweilers, and pit bulls. A 1993 Toronto study found pit bulls accounted for 1 percent of licensed dogs but 4 percent of bites. More ominous is a 2000 study by the Centers for Disease Control looking at 20 years of data on fatal dog attacks in the U.S. Of 238 such incidents in which the breed of the attacking dog was reported, “pit bull-type dogs” were involved in 32 percent, versus 18 percent for rottweilers and rottweiler mixes and 11 percent for German shepherds and mixes. The authors caution that because there aren’t any reliable population figures for specific breeds of dog, we don’t know what percentage of each breed are fatal biters; there might just be more pit bull-type dogs out there.

• In fairness, some other studies haven’t found pit bulls to be conspicuously dangerous. I could probably stack the deck to show that German shepherds were the real menace. Also surprisingly bite-prone: chow chows.

• Much, but not all, of what we’ve learned about dog bites is what you’d expect: In most attacks the victim knew the dog, which was often a family pet, and the attack was close to home. Male dogs were more likely to attack; unneutered males possibly even more so. A disproportionate percentage of dog bite victims are children. Most attacks are provoked, with young children doing most of the provoking. Now for the outlying data point: One study found 94 percent of pit bull attacks on kids were unprovoked, as opposed to only 43 percent of attacks by other breeds. OK, one study, and provocation can be a tough thing to judge. Still.

But let’s be scientific. Here’s what we know: (1) Research to date suggests pit bulls are somewhere near the top of the list of biters, and their bites are bad—and possibly unpredictable. (2) No, Mr. or Ms. Pit Bull Fancier, nobody has proved beyond the shadow of a doubt that they’re particularly violent. (3) Some media claims about pit bulls are ridiculous, no question. Are they powerful beasts with strong jaws? Yes. Do they have “locking jaws”? Spare me. I saw one numbskull report that pit bulls could chomp through chain-link fences. So should you fear these dogs? Let’s not be alarmist. I’ll use my calmest voice-of-reason tone: Especially when children are involved, caution (and maybe some canine-behavior homework) is advised. —Cecil Adams

Is there something you need to get straight? Take it up with Cecil on the Straight Dope message board, straightdope.com.