http://www.straightdope.com/classics/a1_267.html
Having said that, my question is focused in a bit new direction. I understand that people go gray chiefly because of genetics. What I don’t get is why my little 8 year old dog(a miniature dachshund) is getting gray hair around his muzzle.
I mean, he’s a middle-aged dog, but his “hair” is very similar to ours. Shouldn’t it go gray when he’s 50(or never as the case is)?
How does his little dog body know he’s middle aged?
In my experience, people and dogs and cats start to get white/grey hairs when they reach middle age. For a dog or cat, middle age is about 7 or 8. Every (non-white*) dog or cat that I’ve ever known has started graying around 7, and it only gets more pronounced as the animal ages further. For people, it’s about 40 or 50.
Most animals show age in their appearance in one way or another. For instance, what I grew up calling parakeets (budgies) will start losing the stripes on their little feathery foreheads as they age. Hamsters lose hair on their ears. Since a hamster’s lifespan is about 18 months, you want to get a young one.
*My parents have Maltese dogs, which are pure white, so their coats don’t get any whiter with age.
Much like humans, dogs are influenced by their genetic makeup. Some people start greying in their twenties, & some still have a thick head of non-grey hair in their forties. Whatever mechanism in the human mammal tells our hair to start going grey works the same in canines. I know someone with two beagles. Born within a year of each other & from different parents. They are eight years old; one is going very grey & the other looks like a much younger dog, fur-colour-wise.
FWIW: Dogs & cats do not age at the same rate. Large breed dogs have much shorter life-spans generally. Little dogs (except the wider-chested breeds like French bulldogs) typically live much longer. A seven year old great dane or Newfie is old, while a 7 year old poodle is in its prime.
FWIW, I didn’t notice my cat starting to get gray hair until it was about 15 years old. But then, it was a gray cat. Seriously though, it did start to get WHITE hair around its mouth. My cat was really old. She died recently. I miss my kitty.
