With more than 70 million of them running around, the family dog is the most popular pet in America. You trust him with the lives of your family members, but should you?

This May in upstate New York, a pit bull (search) viciously attacked and killed 75-year-old year Bonnie Page. Just a few weeks ago, a canine attack left Edna Dezarn of Arizona clinging for life while in Florida, a woman lost an ear and part of her scalp during another terrifying mauling. 

Over the last twenty years alone, dogs have killed 300 people. That's a disturbing 15 fatal mauling incidents a year.

Dr. Randall Lockwood of the Humane Society (search) says dogs attack for a number of reasons. The biggest is that owners fail to train them properly.

“I think the most dangerous animal out there is people,” he said. “It's what the people do to the dogs or fail to do for the dogs that often creates the dangerous situation for dogs and people.”

Violet and Brian Wilson are still haunted by the horrific mauling of their son Christopher by a pack of rottweilers (search) six years ago

“All I can think of was the pain that he must have suffered that day and how I couldn’t help him,” Violet said.

Eleven-year-old Christopher and younger brother Trammel were waiting for a school bus when three rottweilers escaped from a backyard and charged them. The boys climbed up a nearby tree. Frustrated, the dogs wandered off. After a few minutes, Christopher slid down the tree to see if the coast was clear.

“Christopher got down, because the dogs went away,” Violet explained. “So he had got down… and that's when the dogs came and attacked him.”

When it comes to dog fatalities, rottweilers like those that attacked Christopher are one of the deadliest breeds of dogs. But experts say any canine can be dangerous. In fact, cocker spaniels (search) are known to bite more than any other dog. 

Dr. Lockwood says many owners refuse to neuter their male dogs, creating the potential for a highly aggressive biting machine. One recipe for disaster, he says, is keeping a dog chained up for long periods of time.

“Many of the fatal attacks that we see involve dogs that are chained almost all the time,” he said. “[The dog] is training himself to show aggression towards threatening or scary things, and that can create a very dangerous situation.”

Another dangerous situation is when dogs are left unsupervised. The rottweilers that charged Christopher were allowed to dig their way under a backyard fence and escape.

When faced with the threat of attack, was there anything Christopher could have done to protect himself? To find out, we visited Cheryl Carlson, a dog trainer who specializes in dog attack prevention.

She says that when face-to-face with an aggressive dog, you should turn sideways and avoid eye contact with the dog. Above all, she says, never run away.

If the dog's behavior escalates into a physical attack, Carlson says the most important thing to do — and probably the hardest — is to try not to move. Shouting and hitting the dog will only make the animal more aggressive, and bite even harder.

As a last resort, she recommends you lie motionless with your head covered.

Still, Violet and Brian Wilson believe no amount of defensive positioning could have saved their son. Investigators later learned the three rottweilers had been trained to attack.

“They don't go for your ankles or your foot, you know. They go for your throat,” Brian Wilson said. “That’s how my son died.” 

Police later shot the dogs, and the woman who owned them is now serving 12 years in prison. The Wilsons have planted a garden on the spot where Christopher was killed. They don't want to ever forget his memory, or how dangerous dogs can be.