Doug Franklin wrote:
John Francis wrote:
On Thu, Dec 03, 2009 at 05:12:53PM -0500, Doug Franklin wrote:
P. J. Alling wrote:
At 19 he was a very old dog...
For some reason, I have it in my head that the average lifespan for
pet cats is a couple of years longer than for pet dogs.
That's because they are smaller. Seriously (albeit slightly tongue-in-
cheek; different species are not directly comparable). But large dog
breeds have, generally speaking, shorter lifespans than smaller breeds.
Hmmm. That seems strange, to me. Again, going by biology classes a
lot more years ago than I'd really care to admit, I thought that
larger species typically lived longer than smaller species, when
considered on the "gross scale", like hamster versus cat/dog versus
horse rather than hamster versus mouse. As I recall, something about
the smaller ones having higher metabolism or something (e.g., higher
average resting heart rate). Seems like Basal Metabolic Rate (BMR)
might have been in the explanation somewhere. :-)
The dog's ancestors are an animal of about 30 to 40 pounds, much loarger
than that you start seeing system failures early. Too much smaller and
you have other problems. Pretty much like humans. It takes a lot of
time for all the kinks to work in evolution if you the failures aren't
immediately fatal. I haven't seen a lot of outsized cats. Maybe we
don't have quite as much control over feline breeding, or cats have a
less diverse gene pool. Then again maybe it's just that after a cat
reaches a certian size a human looks more like lunch to a solitary
hunter, as opposed to a pack leader to a cooperative hunter...
--
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