this is just something i was thinking of today,
generally in the animal kingdom, the bigger the animal the longer it lives,eg elephants live for a long time,hamsters only for a few years. isnt it strange then that in dogs,giant & large breeds seem to get old much quicker & dont last as long as the small terriers & toys that seem to be around forever!!!

im quite bored today,hence the subject!!! i wonder why?

My tortoise disagrees with your comments.  :)

oh yeah! forgot about them! whoops holes in the theory already!!!

Why is because dogs were tampered with by man.  They were bred to be much smaller and much larger than nature and natural selection would have allowed them to be in the wild.  A vet once told me that dogs would naturally gravitate to being about 30 lbs in weight.  I have no idea if it's true, but wild dogs (like dingos) seem to be about that size. 

Members of a species that are much larger than they should be seem to run into more health problems than those who are smaller.  It's not uncommon for basketball players, who are often more than seven feet tall, to die very young of heart problems.  Organs just cannot cope with the extra body mass. 

Stacey

thanks!
sometimes i think i know quite alot of stuff, but then (like today) i realise i dont!!! cool at least ive learnt something today!

Heh Michelle,
We learn something new each day!  Anyone who thinks they no it all, should think again!!

Hi Michelled,
I dispute the theory slightly :-) Wolves evolved 60 million years ago, the domestic dog derived directly from the grey wolf, who, incidentally first entered villages in search of food some 12,000 years ago.
The life span of a wolf, or derivative wolf (canine) is from 7-18 years average, or more realistically, 12-14 years.
The grey wolf (canine lupus) is the ancestor of all domestic dogs. The average weight of a wolf is 30-40 kilos so this completly blows the theory out of the water that a dog would naturally gravitate to being around 30 lb. Dingo's are a wild dog that derives from the domestic dog, who in turn, derived from the grey wolf, the oldest species of wolf recorded. Are you following? or have you all lost the will to live yet? :D I know I have ;-) What a great subject, this could start a thread off as to who has the oldest, largest, living canine :D and why they think theirs have lived so long. For starters, I have a Briard who weighs 45 kilos and is classed as a very large breed and allegedly has a life span of 12-14 years, I know somebody who had one until they were 16, who can beat that for a very large breed?