Dog Years: Why Do Small Dogs Live Longer Lives than Larger Breeds – Animal Facts

If you’re a dog lover, and you probably
are if you’re watching this video, you have no doubt noticed that smaller dogs live longer
lives than larger breeds. This is a rather well-known fact. But, why? Let’s try to dig up some answers. Let’s get started. But, before we start, take a moment to like
and subscribe for more fun, fauna facts. When compared to the lifespan of other mammals,
“smaller size, longer life” would at first glance appear to be illogical, especially
if your family has had short-lived pets such as rats, hamsters, or gerbils. Compare their lifespans of about 2-4 years
to an elephant that can live up to 70 years or the 65-ton Bowhead Whale that can live
an estimated 200 years, it seems larger mammals have longer lives. Scientists think that this happens because
of the way differently-sized animals use energy. Big animals’ cells are slower and more efficient,
so their parts wear out slower and last longer. Also, the mouse and the elephant have approximately
the same amount of heartbeats in their lifetimes, albeit the mouse’s heart beats at a much
higher rate. We should expect a Great Dane to live longer
than a Chihuahua, by this logic, but, as you know, that’s not the case. The Great Dane only lives, on average, 6 or
8 years, while the Chihuahua can live up to 18 years. Forget about all the other mammals and focus
on just one species, though, and you see this trend reverses, across many species of mammals. Scientists have seen this is in mice, horses,
and even humans and the effect is quite pronounced in dogs, which have a pretty extreme range
of sizes from Mastiffs weighing 250 pounds to a Chihuahua named BooBoo that breaks the
scale at a staggering 1.5 pounds. Personally, I would have named him something
like Crusher or Bruiser. Anyway… In a study from a few years ago, led by Dr.
Cornelia Kraus, a research scientist and evolutionary biologist at the University of Göttingen
in Germany, researchers analyzed mortality data in over 56,000 dogs from 74 different
breeds. Kraus states that they found that for each
increase of 4.4 pounds of body weight, a dog’s lifespan decreased by 1 month. So why, then, do small dogs have a longer
average lifespan than the larger breeds? Well, they’re still unsure, at least at
the time of this recording. But, at it’s simplest, Dr. Kraus suggests
that there are several possibilities, including that larger dogs may succumb to age-related
illnesses sooner. Also, larger breeds grow from puppies to adults
at an accelerated rate, compared to their tinier kin, and this may lead to a higher
likelihood of abnormal cell growth and cancer. And, scientists think that the reason big
breeds die young has to do with the way humans have bred them and the way they grow. Larger dogs grow very big very fast. Take a one-year-old Great Dane, for example. From birth to his first birthday, he increases
100-fold in weight increasing from 1-2 pounds at birth to 95-140 pounds at 1 year. In that same time frame, wolves increase 60-fold,
poodles 20-fold, and humans only about threefold. Research in the last decade has suggested
that larger individual animals die younger because this sort of accelerated growth may
come with increased free-radical activity, that can damage tissue and DNA. We know that there are at least 3 genes that
determine large body size in dogs, IRS4 and IGSF1, involved in thyroid hormone pathways
which affect growth, and ACSL4, involved in muscle growth, and backfat thickness. But, more studies are needed on how this accelerates
aging. These findings are just the tip of the iceberg
in our understanding of canine lifespans (and even human lifespans) and what determines
them. Scientists plan future studies to better explain
the link between growth and mortality. Want more fun, fauna facts? Go ahead and smash that subscribe button and
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11 Responses

  1. Animal Facts says:

    Thanks to Jenna Marbles for making some of her Chihuahua videos Creative Commons –

  2. Lily Seven says:

    I have wondered about that! Thanks for this video

  3. baby alive and me baby alive and me says:

    Thank you. cuz I have two little dog's😻

  4. Deku Kitty says:

    After watching the video, it does make a lot of sense. Very large animals usually take a long time to grow. Meanwhile dogs reach maturity at roughly the same age, regardless of size. People have found that you can improve the lifespan and health of larger dogs by making sure they grow more slowly. (Basically by not overfeeding them.) The lifespan increase isn't by much, but it does show that growth rate has some impact on lifespan.

  5. Janus Loggins says:

    That makes a lot of sense as to why little dogs live longer. I just wish that they could live as long as we do.

  6. TheIlluminator says:

    Very interesting. Thanks for sharing…

  7. Jacob StPierre says:

    So that's why we got ozzy the havanese 🙂

  8. mark says:

    sure the video is decent and informative. but the editing is absolutely horrendous. that toxic happy non copyright music scattered all over the video and the reminders to like. the transition effects and the subscribe button at the start is just a green screen job and is horrendous.

  9. Reid Steckelberg says:

    Logged in to dislike this, why would you make a video titled why do small dogs live longer than larger breeds if as you claim at around 2:20 into the video that scientists don’t know?

  10. Steven Gorum says:

    I can't hear you cuz the f**** music's too loud

  11. Steven Gorum says:

    I'm talking about dogs

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