Morgan Shumard and fiance Tim Self are experienced dog owners, but they weren't entirely sure about Norton, a 70-pound pit bull, after they fell in love with him on a website. • It's not the breed. The couple in Burton, Mich., had lost a pit bull and were in search of another. It's that Norton is completely deaf.
They were nervous about whether they could train him, and how he would fit in with their two other dogs, a midsize English bull terrier and a chihuahua. They were concerned he might be too skittish and nippy to mix with their young nieces.
They needn't have worried.
A rescue group that saved Norton from euthanasia after he was left with a veterinarian taught him some basic sign language that his new family built on using treats and repetition: an "okay" sign placed on a forehead for "drop it" and a thumbs up for praise.
"In the beginning, when the dogs would all play fight, it would get rougher, and it was a big change from being able to communicate with a dog verbally," Shumard said. "I was worried about him being startled or running all over the other dogs, but he's very sweet, very tuned in."
Six months after his adoption, 2-year-old Norton is the hit of the neighborhood. "He uses our other dogs to hear noises for him," Shumard said. "When he's asleep we tell Gracie, our bull terrier, to go wake him up, and we stomp to get his attention so he can feel the vibrations. I call him my one-in-a-million dog."
The prevalence of hereditary deafness in dogs, the most frequent cause, isn't known across breeds, but the likelihood increases with the presence of white pigmentation, either in patterns or solids, said Dr. George Strain, a professor of neuroscience at Louisiana State's veterinary school in Baton Rouge.
About 90 breeds are most affected, he said. There's also a strong correlation between deafness and blue eyes.
Dalmatians have the highest prevalence of deafness in the United States, Strain said. Based on hearing tests he conducted on 5,638 of the dogs, he found 7.8 percent (or 411) were deaf in both ears and 21.7 percent (or 1,226) were deaf in one ear.
Other causes of deafness include old age, medical treatment with certain antibiotics and other drugs, and hearing damage from proximity to explosive noises, such as those experienced by hunting dogs.
Detecting deafness in puppies is complicated, Strain said. The condition doesn't develop until a few weeks after birth, and can be masked because stricken pups use littermates to figure out such things as when to nurse. That's why a multidog household can work better for a totally deaf canine, he said.