How powerful is a dog's bite?

By Dr. John KochQUESTION: I know that a dog's bite is very powerful. How much pressure can be applied by a dog's jaws when it bites?

ANSWER: Some dogs are capable of applying between 500 and 700 pounds of pressure per square inch when they bite. The jaw strength of dogs is six times stronger than what is possessed by humans. The dog can use this strength to kill, to cut flesh and to break the bones of its prey. These abilities are important to survival of the dog in the wild.

The mouth of the dog is also specially adapted to what it must have to effectively function in an undomesticated environment. The dog has 42 teeth compared with 32 in humans. There are 20 upper teeth and 22 lower teeth. The incisors, which are the small teeth located in front, are used to pick up small objects. The large canines are next and are used to kill prey. Next come the premolars and molars. These teeth have a scissor-like action and cut bone, tendon and muscle.

Typically dogs do not chew their food like humans do. They use their teeth to simply cut their meal into chunks just small enough to swallow. This tendency can occassionally lead to choking.

Every year there are between 1 and 3 million humans bitten by animals in the United States. Of these, between 80 percent and 90 percent are bitten by dogs. There are between 10 and 20 deaths from dog bites each year in this country. Most of these are children. Dog bites are no joke. In addition to the wound itself, bites can spread infection, tetanus and rabies. Dogs that bite can cause legal problems and cause you to have your homeowners insurance canceled. People often have valued dogs for the protection they provide. Unfortunately the line between being a good watchdog and biting innocent people is very fine.

Dr. Koch is a Cape Girardeau veterinarian.