I want to hear more about the human part of this theory. Do large people indeed have a shorter life span?
Fascinating. Do you have a cite for this?
muttrox: Here is an abstract for a course which mentions the 1/4-power scaling. This paper states
I’ve also seen an exponent of 1/5 in a few places, like here, where the lifespan of mammals is given as L=11.8M[sup]0.20[/sup] (L = lifespan in years, M = mass in kg), and the lifespand of birds is given as L=28.3M[sup]0.20[/sup].
The actual reference I used for the initial statement was a comparative animal physiology text: Schmidt-Nielsen, Knut (1990) Animal Physiology: Adaptation and Environment, 4th ed.
The answer to your question is going to depend on exactly how you define “large”. If you define “large” according to physical stature and compare relative mortality statistics, you will find that taller people generally have a lower incidence of mortality, but only up to a point. Beyond this point, this trend reverses, and added height increases mortality risk. A Norwegian study placed the optimum height at 6’-4" (193 cm) tall, which happens to be my height. Naturally, I concur with these findings. 
Alternatively, if you use Body Mass Index to define “large”, you will find that people with a high BMI (typically fat people) carry a significantly higher mortality risk. But this is not uniformly the case, as people who are very thin also have an increased mortality risk. Furthermore, this relationship doesn’t seem to hold for all age groups. You can read more here:
How bout a tall, lanky bastard such as myself?
I hate small dogs. Small dogs live longer just to annoy me.
I’m sorry that I can’t provide an adequate cite, but there was a study done here in Canada several years ago, (c. 1997) the gist of which was that larger (more massive) people do tend to have a shorter natural lifespan, while smaller people are more likely to die in accidents. (The average lifespan was still considerably longer for us tiny ones, with the exception of people with dwarfism.)
I remember this because of a water-cooler discussion I had with my boss about it-- he said something like, “You stay home in bed and be smug about how old you’re going to get-- me, I can fall down the stairs with confidence.” What a great guy!
:previews:
Why do I bother?
Well at least I am short and working on the body mass thing. I have lost 38 pounds.
I love little dogs and have read on another bulletin board that they do live longer. They can even live to 20. It was in an About.com bulletin Bulletin Board.
Little dogs can’t put their head on the counter, can be hugged like a little baby, and don’t necessarily bark and are nervous. My t-cup poodle is basically mute. A surprised bark comes out once in a while. They can be bred for that. Puppy Mills are a big problem for breeding nervous and loud pups.
…That frightens me so much, I don’t even know where to begin. Uhm.
Big dogs don’t need to put their heads on the counter. You train them not to counter surf. It’s not that hard. There’s a whole lot more of a big dog to hug, plus you can wrestle. Where’s the fun in playing with a dog you might squish if you look at it the wrong way? Overwhelmingly, the large dogs I’ve met are FAR less prone to yappy fits of hysterics than the small dogs. And why, in ye gods’ (and goddesses’) names, would you buy a dog from any breeder who’s breeding program focus is producing nervous, mute dogs?
I dunno, I guess I’m rather jaded against small dogs, because of their owners. It seems that many owners of small dogs often don’t bother to train, or correct behavior, because misbehaving, aggression, hysterical barking, whatever, in a five pound dog is “cute”… as in, oh look how tough fluffy thinks he is picture snarling, hate filled ball of fluff who then proceeds to pee on everything because his owner didn’t neuter him because “he’s just so cute and we’re thinking about breeding him” Such behavior just isn’t tolerated with larger dogs.
I have no formal proof of this, but I managed a pet store and grooming shop for years and grew up in a vet hospital. I’m fairly certain in saying that the number of small dogs who bit people, peed on things, or destroyed stuff, is exponentially higher than the number of larger dogs. Also, in grooming dogs, it was never, ever the pit bull types or shepherds that I had to worry about taking a chunk out of my hand.
But again, I don’t so much blame this on the dogs as on their owners.
Peace,
~mixie
Where is the scientific documentation that this is correct?
I’ve heard the same about horses, but have found little to back it up other than anecdotal “evidence.”
I don’t have a cite, but it is an accepted fact in the veterinary community. I’m not a vet, but I’m married to one and life expectancy does vary inversely with size. Expected lifespan is pretty important to small animal doctors as owners will always want to know how many years a dog can expect to live before dropping a bunch of cash on an expensive procedure.
This thread is interesting and I’ll see if I can post her ideas on the subject before the day’s out.
That seems amazing to me that the Chinese imported Pomeranians from what is now modern day Germany and Poland.
http://www.polishroots.org/genpoland/pom.htm
Maybe you are thinking of that other little yipper, the Pekingese?
Back to the OP, I have a Great Dane and have done some research there. In that breed and many other giant breeds, there is a propensity toward cardiomyopathy. This disease has been a major culprit in the shortened lifespan of the Great Dane.
Well, I posed the question to my wife the VMD, and she feels that it basically comes down to the human meddling that breeding for the specific trait of size is.
The larger breeds are simplyy genetically more suceptible to disease, cancer being a very common one. A good example is a Great Dane - she’d be very surprised to see an elderley (7yr old) great Dane that doesn’t have osteocarcoma (sp?). The rapid bone growth at a younger age leads to this disease in later life.
With every dog breed your vet will be able to tell you what they will probably die from as various breeds are simply statistically more likely to develop certain diseases. The bulldog is a mess from the start though.
Mutts are recommended as they are generally healthier than purebreds in the long run.
YMMV, of course.
I think it’s largely due to lifestyle differences. Studies have shown that the larger breeds of dogs tend to engage in higher risk-taking behaviors, such as smoking and reckless driving.
Slight clarification: I’ve got a Carolina Dog who’s more like 60 pounds than 30-40, and all the other Carolina Dogs I’ve met (admittedly few) have been in her general size range as well. Not huge, but probably considered a Large Dog (as opposed to giant breeds like Great Danes, St. Bernards, &c.). She’s eight and a half years old and in great physical condition, though graying about the head and muzzle; she had hip trouble for a while, but it appears to have subsided.
More info here (better info than the .org site):
I said my dog is not nervous. She weighs 3 lbs. and is completly trained to hand signals and voice commands. She is also spayed. I believe all pet dogs should be spayed.
She fits very well into a mobile home. She is litter box trained and never pees on the carpet.
My vet said she could easily live to age 20.
I have had large dogs before, in a home with 5 acres, including Rottweilers and German Shepherds, and have trained them and some have taken 1st place in their obedince classes. These dogs have been donated to the police department. I have fostered dogs for the police department and the vet has said the large dog’s life span is around 13 to 15. Collies have the shortest lifespan with 12 years being tops. I can not substantiate that. It is what my vet said.
I much prefer my little dog, because she is what I want in a dog. She is completely obedient, very intelligent and tiny to pick up and cuddle like the baby I want.