Or do they? Is there any scientific evidence to show there’s a correlation between size (of members withing a particular species) and longeivity? I’ve heard the same thing about horses, but it’s alway anecdotal.
Well, my vet agrees with it - he sais 10-11 years for a large dog is considered decent, where as 13-15 for a small dog is the norm. Sadly, I don’t know where he got this info.
I wish I had a cite for you, but I don’t. The last time I was in the vet’s office, there was a poster on the wall so you could equate how old your dog is in “dog years”. The smaller dogs aged faster earlier, yet the bigger dogs caught up after a year or so and surpassed the smaller breeds. Of course, barring any genetical issues and that you’re a good pet owner, dogs can live to somewhere around 10-16 or so years.
Most dogs I’ve had on average lived to about 13. I also heard that mutts live longer because they are not predisposed to inbreeding. Whether or not this is true, I have no idea. But since I saw the breed size chart in the vet’s office, I would surmise this to be fairly close to true. I have a wonderful vet (the best in Ohio, IMO) and I would hope he wouldn’t post something to be untrue. But the science world is always changing, so who knows what it will be 5 years from now.
If you Google a bit, you can find a few sites listing life expectancy by breed, but none of them list their sources. Of the lists I found, it looks like the “smaller = longer life span” is generally true, but it’s not a linear progression. For example, according to one site, bulldogs seem to have the shortest life expectancy (6.7 years), but are certainly smaller than Great Danes (8.4) or mastiffs (8.6). I suspect that size is a large factor, but particular breed’s tendency toward certain ailments (bulldogs are prone to respiratory ailments, IIRC) are just as much of a factor.
I don’t know if anyone has really done a hard study on this. It’s so difficult to control for environmental factors. But yes, speaking as someone who has worked in the Veterinary industry for a while, small breed dogs tend to live longer than large breed dogs. But, like any trend, you’ll find cases where it’s true and cases where it isn’t.
Also, to nitpick PinkMarabou slightly, mutts live longer because they are not inbred, not because the are indesposed to inbreeding. Inbreeding increases the chances that a bad genetic trait will be displayed. Mutts, by drawing off of a very diverse genetic pool, are less likely to have regressive, detrimental congenital diseases. Once again, oesn’t mean it never happens, though.