November - Senior Pet Month

Most dogs are considered "senior" at around 7 years of age. This number may be higher for small breed dogs and slightly lower for large breed dogs.

It is hard to believe that Ebony, my black lab/border collie who still acts like a puppy, has now hit the "senior" age bracket. She has begun to get some gray hairs around her chin, too.

"Senior" Ebony with Beard

If your dog is five years old, does that means he is the same physiologic age as a 35-year-old person? Not exactly. The theory that every year in a dog's life is the same as seven years in ours is commonly known, but not very accurate. Size and breed play a major role when considering the age of your dog.

For a more accurate comparison between physiologic age of dogs, follow this formula:

A one-year-old small or medium sized dog is about 15 human years old. When the dog reaches two, he is the equivalent of a 24-year-old person. After that, each year is about four human years. This means that a seven-year-old dog is about the same as a 44-year-old person.

Large and giant breed dogs initially age slower but then age quickly. At one year of age, the dog is about the same physiologically as a 12-year-old child. After that, each year follows the standard seven human years. For giant breed dogs, five years old is considered the beginning of old age.

The average canine life span is around 12 years but differs from breed to breed. By the time most dogs reach seven years of age, they are entering their senior years. The record for the longest canine life span is 29 years.

Study on Longevity in Dogs

Since the earliest domestication of wild dogs, human beings and canines have been nearly inseparable.

With the passing of time, we have evolved behaviors that cater to the dog's best interests. We have also worked to bring out the traits in them that we find most desirable while simultaneously suppressing those with which we disagree. This has been done through careful application of selective breeding, giving rise to specialized dogs with singular purposes. But a new study shows that in addition to changes in behavior, this artificial selection has also had an effect on canine longevity.

According to the study, to be published next month in The American Naturalist, calmer, low-energy dogs live longer than their bolder, higher-energy counterparts. The scale upon which the docility of the dogs is measured was first introduced in a Journal of General Psychology study in 1995. According to that scale, the mellow Springer Spaniel is 34 percent more docile than a Basset Hound and is twice as likely to live past ten years of age. Poodles, being 24 percent more docile than Boxers, are four times as likely.

The new study’s author Vincent Careau, along with colleagues at University of Sherbrooke in Quebec, was careful to compare dogs of a similar size only and collected the data for the paper from studies done previously. Using this information, he has arrived at what he is calling an “undesired correlation into longevity.”

The greater impact and implications of this study remain to be seen.