Yesterday, for the first time in more than 14 years, I went for a long walk by the river without my dog Bella. These days she's still keen to go for a walk - but it's more like an amble. A v-e-r-y s-l-o-w amble. And after 2-3 km that's it for the day. Her age is catching up with her.
Now, Bella's a golden lab. And 14 is a good age for that breed, going by the age/breed chart on the vet's wall. Especially because we've managed to keep her slender (a hard task with a lab!) & fit. Yet one of her friends, a little bichon, is much the same age but still leaping about like a young thing (as the age/breed chart suggests for her). So why do big dogs often seem to age (in relative terms) faster than little ones? And why do dogs age more quickly than humans?
There are few animals that have similar lifespans to those of humans - offhand I can think of elephants, turtles, & some fish. You could argue that up until recently, people were lucky to get beyond their 40th birthday. In the Western world, at least, advances in nutrition & medicine have seen that change. But then, in that same part of the world humans besotted with their pets tend to apply the same advances to their companion animals' well-being...
There's the possibility that, in selecting for size, we've also inadvertently selected for something else that shortens life. Something that impacts on the telomeres of big dogs, perhaps? Although that's not a universal feature, because there are smaller dogs - bulldogs, for example - that tend to lead shorter lives as well.
Hmmm. I have to say that I don't actually know. And so far, I haven't managed to find out. So view this as an open thread - suggestions, anyone?