Speaker 1: Welcome to brain Stuff, a production of iHeart Radio. Hey,
Speaker 1: brain Stuff, learn vogal bomb here. Have you ever wondered
Speaker 1: why you seem to know a lot more elderly Chihuahuas
Speaker 1: than aged Rottweilers. It's just a fact of life that
Speaker 1: small dogs, if they escape disease or misadventure, live longer
Speaker 1: lives than larger ones. This trend has puzzled veterinary researchers
Speaker 1: for as long as we've been fussing over our faithful
Speaker 1: four legged friends, and it's a mystery that hasn't been
Speaker 1: definitively solved. Conventional wisdom in the animal world dictates that
Speaker 1: between different species, larger animals live longer than smaller ones.
Speaker 1: For example, an elephant can live into its seventies, while
Speaker 1: a mouse might only have a year or two to
Speaker 1: do its earthly business. However, the opposite seems to be
Speaker 1: true within single species subsets, and although dogs come in
Speaker 1: lots of shapes and sizes, they're all the same species.
Speaker 1: The average lifespan for an enormous dog is around seven
Speaker 1: or eight years, while a tiny dog can reliably live
Speaker 1: to the ripe old age of fourteen or fifteen. The
Speaker 1: popular adage that one human year is equal to seven
Speaker 1: dog years isn't supported by modern science. Although it's easy
Speaker 1: math and therefore sticks around. The truth is more complex.
Speaker 1: In the first year of a dog's life, it generally
Speaker 1: reaches the physical maturity of a fifteen year old human.
Speaker 1: The second year adds another nine years, and after that
Speaker 1: the rate of aging varies widely based on breed and size.
Speaker 1: A small dog is considered senior at around age eight,
Speaker 1: while a large dog hits old age around five or six.
Speaker 1: Researchers know this, but they're not entirely sure why, and
Speaker 1: to be fair, it probably involves a combination of a
Speaker 1: lot of different factors. It turns out that a dog's
Speaker 1: size isn't the only, or even the primary factor that
Speaker 1: determines lifespan. Genetics and breeding also play a role, with
Speaker 1: certain breeds being more vulnerable to certain life threatening or
Speaker 1: life shortening diseases and conditions than others. Basically, although the
Speaker 1: aging process for dogs is very different than it is
Speaker 1: for humans, it's also very different. Among dogs. The features
Speaker 1: that a dog has been bred for seemed to matter
Speaker 1: more than size. There was a study published in April
Speaker 1: two in the journal Nature based on a massive database
Speaker 1: of veterinary records from the United Kingdom, and to keep
Speaker 1: it simple, they looked at the lifespans of pure bred dogs.
Speaker 1: Small jack Russell Terriers, and midsized Border collies differ substantially
Speaker 1: in size, but according to the study, they live pretty
Speaker 1: similar lifespans twelve point seven and twelve point one year's respectively. However,
Speaker 1: flat faced breeds like pugs and French bulldogs were found
Speaker 1: to have much lower life expectancies due to breathing problems,
Speaker 1: a disease, and difficulty giving birth. The French bull dogs
Speaker 1: life expectancy is only four point five years, and none
Speaker 1: of the other flat faced breeds, no matter how small,
Speaker 1: were found to have an average lifespan of more than
Speaker 1: seven point eight years. Okay, but why might size matter.
Speaker 1: It might have to do with how long it takes
Speaker 1: a dog to become full grown and the difference in
Speaker 1: size between its puppy body and its adult body. It
Speaker 1: seems that growing very large, very quickly takes time off
Speaker 1: of a dog's overall life span. Take, for example, a
Speaker 1: Great Dane. In the first two years of their life,
Speaker 1: they reach their full size, which can be over thirty
Speaker 1: or eighty centimeters tall, and some a hundred and seventy
Speaker 1: five pounds around eighty kilos. That's a lot, and it
Speaker 1: apparently takes a toll. Large breeds die of cancer more
Speaker 1: often than small breeds, a trend that researchers believe has
Speaker 1: to do with how quickly they grow in their first
Speaker 1: year of life. With all that rapid expansion, it possible
Speaker 1: that abnormal cell growth is more likely, or because their
Speaker 1: lives play up more quickly, that they succumb to the
Speaker 1: diseases of old age earlier than say a chihuahua. It
Speaker 1: takes a chihuahua about ten to twelve months to grow
Speaker 1: to full size, but that size usually maxes out at
Speaker 1: only about eight inches or fifteen centimeters tall and six pounds,
Speaker 1: which is just under three kilos. It's just not as
Speaker 1: taxing on the body to become a full grown chihuahua
Speaker 1: as it is to become a complete great dane. Finally,
Speaker 1: lifestyle and access to veterinary care can affect longevity, and
Speaker 1: these factors can depend on the role of the dog
Speaker 1: within the family. For example, toy dogs may be pampered
Speaker 1: more than larger breeds given their lap friendly size. And
Speaker 1: all of this isn't just important in terms of figuring
Speaker 1: out how we might all spend more time with our
Speaker 1: beloved companions a dog. Research is also important because dogs
Speaker 1: die of the same illnesses that humans do, including answer
Speaker 1: heart disease and diabetes, and so as usual, learning more
Speaker 1: about them may help us learn more about ourselves. Today's
Speaker 1: episode is based on the article the longest living dog
Speaker 1: breeds are tiny, but Why on how stuff works dot Com,
Speaker 1: written by Jesslyn Shields. Brainstuff this production of I Heart
Speaker 1: Radio in partnership with how stuff works dot Com, and
Speaker 1: it's produced by Tyler Clang. For more podcasts, my heart
Speaker 1: Radio is the I heart Radio app, Apple Podcasts, or
Speaker 1: wherever you listen to your favorite shows.