Typically larger species live longer than smaller ones, however if you look at dogs small breeds live longer than large ones. Why? :hmm:
Larger species tend to be more complex and have longer reproductive cycles. Larger size in an individual puts more stress on the system. I imagine smaller humans tend to live longer too.
Quote from: Peter Wiggin on November 22, 2011, 08:10:52 PM
Larger species tend to be more complex and have longer reproductive cycles. Larger size in an individual puts more stress on the system. I imagine smaller humans tend to live longer too.
But larger breeds are more similar in size and shape to the Wolf which was the species that they were bred from. One would think that would lead them to being healthier and the little freakshows which are gross deviations in size and shape from the base form would be less healthy. However it turns out to be the opposite.
Random guess: less cell division, and hence less shearing of the telomeres/opportunities for mistakes in replication, and hence less genetic damage undertaken, in the process of reaching nominal size in a smaller individual than in a larger individual.
Big dogs are more likely to be outside so they get hit by cars more often.
Quote from: MadImmortalMan on November 22, 2011, 08:16:36 PM
Big dogs are more likely to be outside so they get hit by cars more often.
Well that's true, but even taking that into account the average Irish Wolfhound last just 7 years while a Beagle will live 13.
Smaller stuff breaks faster.
I assume it what they were bred for. Larger dogs are working dogs. They were breed to live hard, which often means a shorter life span. Lap dogs weren't bred with this in mind. They were there to live longer. Big Dogs have only become pets in the modern sense a short while ago (relativiely).
Or you can go the genetic route. all dogs are basically in a prolonged neonatal wolf state. Small dogs are more neonatal so retain youth longer and live longer.
Quote from: HVC on November 22, 2011, 09:24:13 PM
I assume it what they were bred for. Larger dogs are working dogs. They were breed to live hard, which often means a shorter life span. Lap dogs weren't bred with this in mind. They were there to live longer. Big Dogs have only become pets in the modern sense a short while ago (relativiely).
I think part of the problem is that some many of these large breeds are relatively new or have been conserved and refounded from small inbred populations.
If you actually had them do the work they were originally bred to the chaff would be shed very quickly and stronger and more healthy dogs would be the only ones to survive to breed. As it is most are bred for a specific aesthetic look that has nothing to do with how good the dog would have been at its original job.
Siberian Huskies for example are a relatively large dog but they're healthy, have few genetic defects and can live from 10-15 years. This is doubtlessly due to the fact that they have been worked hard within recent times. Can't pull a sled if your hips displace. Can't do the work and the owner won't breed you.
Basically my solution is that if the wolves in Wyoming must be culled, then we should only use wolfhounds and broadcast the hunt live on tv.
Quote from: jimmy olsen on November 22, 2011, 08:24:12 PM
Quote from: MadImmortalMan on November 22, 2011, 08:16:36 PM
Big dogs are more likely to be outside so they get hit by cars more often.
Well that's true, but even taking that into account the average Irish Wolfhound last just 7 years while a Beagle will live 13.
Well, it's not just getting hit by cars. Dogs that spend a lot of time outside are probably more exposed to more parasites and diseases, and other hazards as well.
Quote from: dps on November 22, 2011, 10:42:11 PM
Quote from: jimmy olsen on November 22, 2011, 08:24:12 PM
Quote from: MadImmortalMan on November 22, 2011, 08:16:36 PM
Big dogs are more likely to be outside so they get hit by cars more often.
Well that's true, but even taking that into account the average Irish Wolfhound last just 7 years while a Beagle will live 13.
Well, it's not just getting hit by cars. Dogs that spend a lot of time outside are probably more exposed to more parasites and diseases, and other hazards as well.
Hmm...this is true.
However I wasted a good amount of time actually looking up academic studies of what kills big dogs and the leading causes are mostly all cancers and weird congenital defects. Goes back to the inbreeding and selecting for aesthetic traits instead of selecting them for the ability to actually hunt or do work.
However as gene sequencing plunges in price there seems to be a lot of hope among breeders that many genetic defects can be breed out of the gene pool.
The heart doesn't scale up as much as the rest of the body in big dogs, as such it has to work harder.
The short lifespan of dogs is one of the saddest things in the universe :(
Like Tyr said, it's stress on the circulatory system and the joints.
There's probably a similar factor at work to the recent discovery that tall people get cancer more - basically the more cells you have, the more there is to go wrong.
Quote from: Tyr on November 23, 2011, 03:15:48 AM
The short lifespan of dogs is one of the saddest things in the universe :(
yes, hearthbreaking :(
Quote from: Brazen on November 23, 2011, 04:40:01 AM
Like Tyr said, it's stress on the circulatory system and the joints.
There's probably a similar factor at work to the recent discovery that tall people get cancer more - basically the more cells you have, the more there is to go wrong.
Wolves are on par with the largest dogs in size, though not weight and they'll live on average 6-8 years in the wild but live 12-15 in captivity. They live a rough active life but are healthier.