Large dogs age faster, die younger

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Most large owners know they are setting themselves up for heartache because their beloved pets will die much sooner than smaller breeds.

The correlation between size and lifespan in is well documented, but scientists are still unclear about the reasons behind it. Why, for example, does a 150-pound Great Dane only live for about 7 years, while the average lifespan of a 9-pound toy poodle is 14 years?

“This tradeoff has been known about for a long time, but nobody has yet investigated the underlying demographic mechanism,” said , an evolutionary biologist at the University of Göttingen in Germany.

For example, veterinarians recommend starting geriatric checkups for small around age 11, for medium-sized dogs at around age 9, and for large dogs around age 7.

One might assume from this that large age , said, but it could also be that they just started aging earlier, and thus develop age-related problems sooner.

In order to distinguish between these two hypotheses, Kraus and her team analyzed demographic data, including age and cause of death, for more than 50,000 from 74 breeds taken from the Veterinary Medical Database, a compilation of pet-health data from North American veterinary teaching hospitals.

The researchers also considered a third possibility: large dogs may just have an increased mortality risk throughout their lives, regardless of their age. In other words, their “baseline” mortality rate is higher than that of smaller breeds.

Each of these three hypotheses generate different so-called “mortality curves” — a chart that results when mortality risk is plotted against age on a graph.

When the different dog breed data from the database was graphed, its curve most closely matched the one predicted by the faster-aging hypothesis.

“That’s where we really see a strong correlation,” Kraus said.

The analysis also indicates that large dogs age at an accelerated pace, such that “their adult life unwinds in fast motion,” the authors write in a new study that will be published in an upcoming issue of the journal The American Naturalist.

The new findings are a valuable first step toward answering the question of why large dogs die young, said , an aging researcher at the University of California, San Francisco.

“I think what’s really nice about this study is that these are not lab animals,” said Kenyon, who was not involved in the research. “They’re animals out their lives in the real world.”

Future studies might also investigate why larger dogs age faster, something that the current study doesn’t address, Kenyon added. One intriguing clue, gleaned from previous studies, is that small dogs have lower concentrations of the growth hormone IGF-1, or insulin-like growth factor 1, in their blood than large dogs.

High levels of IGF-1 has been shown in a wide variety of organisms, including humans, to be associated with increased risk of death from age-related diseases such as cancer and heart disease. Conversely, manipulations that lower IGF-1 levels in many animal species slow their rates of aging, reduce the risks of age-related disease and extend their lifespans.

The new findings “might give the sense that the reason large dogs age faster is because they grow faster. But we don’t know that,” Kenyon said.

It could be that large die because they have more IGF-1 – their large size might just be a side effect of having higher concentrations of the growth hormone.

One way to test this hypothesis would be to “take a small dog, and give it high levels of IGF-1 when it’s young so it becomes a large dog,” Kenyon said. “Then, when it’s an adult, go back to a lower level [of the hormone], and see if you still get a long lifespan. I think that would be a very interesting experiment to do, but it has not been done.”

Such an experiment could provide further proof that IGF-1 plays a critical role in the aging process. Furthermore, the fact that small dogs – which naturally have lower levels of IGF-1 – are often healthy throughout most of their lives could suggest that the IGF-1 pathway could be manipulated to make organisms live longer.

“This really argues that perturbations in this pathway that increase lifespan wouldn’t necessarily make you sick in any way or have a detrimental effect on your health,” Kenyon said.

Study first-author Kraus urged caution in extrapolating her team’s findings to humans.

There is some circumstantial evidence that taller individuals have shorter lifespans, Kraus said, but “it is incredibly difficult to study this in humans because we have so many environmental factors that affect our height.”

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Comments

    • ActionChaos0
    • March 12, 2013

    GTA + Assassin’s Creed + Max Payne = Watch_Dogs

    • Kaleb Taylor
    • March 12, 2013

    Ubisoft already answered the question about the fusebox.

    • vortexmist
    • March 12, 2013

    I’m sorry but his accent made me laugh.

    • Michael Leon
    • March 12, 2013

    woah, ac1 and 2 were good. at least, 2 was good. 1, even though it was the original idea of the assassins vs templars put to use and had a lot of potential, it made a lot of bad design choices. ac2 fixed that, while maintaining the cool story about all these assassins and conspiracies which fitted into the renaissance setting, also paralelling the rebirth (renaissance) that 2 was to the whole series. it was slick, fast, and awesome.

    • TheMrzucker21
    • March 12, 2013

    OMG I am disappointed, I have no money for a PS4, I have only one ps3 -. –

    • Michael Luke
    • March 12, 2013

    Scripted Watch Puppies

    • Fabio254
    • March 12, 2013

    No it’s actually pretty bad.

    • Kwankapog
    • March 12, 2013

    wHO SAID IT WAS IN THE FUTURE?

    • Kwankapog
    • March 12, 2013

    With slight variations. it looks like a modern day city

    • austinroxout
    • March 12, 2013

    wow…. click show comment to go on a magical adventure! no but seriously Baker you are the childish one here.

    • djmonkeyleaderz
    • March 12, 2013

    assassin greed?

    • Thanhda Tie
    • March 12, 2013

    they are the same creators of assassin greed. so why you hating?

    • PBJTIME79
    • March 12, 2013

    Can’t wait for ac4

    • JVson002
    • March 12, 2013

    I want this game, I WANT THIS GAME!!!

    • Johnny Torion
    • March 12, 2013

    Is this gonna be a series or a standalone?

    • crazymadness25
    • March 12, 2013

    1.doesn’t look lik an explosion to me…
    just sparks…
    2.it’s not important if it would be like that in real life…
    it just needs to be realistic/authentic…
    …meaning it should be BELIEVABLE in the moment it happens…what i think i was…

    btw. did you notice the moment where suddenly the time was elapsing slower…that was really strange… ;-]

    • Michael Luke
    • March 12, 2013

    Chicago… that’s the only reason I’m buying this game.

    • kinostar11
    • March 11, 2013

    Why do people compare this to AC? What the fuck

    • Franky Ruggeri
    • March 11, 2013

    I want that Game!!!!!!!

    • silverpeak24
    • March 11, 2013

    Lookes like you have a kid to kill Mr 47.

    • Ikuzke123
    • March 11, 2013

    XD

    • LilEvsBEAST
    • March 11, 2013

    Guess what im getting!

    • Josh Belenke
    • March 11, 2013

    first time i have ever seen this game. I WANT THIS SO BAD!

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