WEBVTT - Why Do Small Dogs Live Longer Than Large Dogs?

0:00:01.800 --> 0:00:06.920
<v Speaker 1>Welcome to brain Stuff, a production of iHeart Radio. Hey,

0:00:06.960 --> 0:00:11.200
<v Speaker 1>brain Stuff, learn vogal bomb here. Have you ever wondered

0:00:11.240 --> 0:00:14.080
<v Speaker 1>why you seem to know a lot more elderly Chihuahuas

0:00:14.120 --> 0:00:18.119
<v Speaker 1>than aged Rottweilers. It's just a fact of life that

0:00:18.280 --> 0:00:22.320
<v Speaker 1>small dogs, if they escape disease or misadventure, live longer

0:00:22.360 --> 0:00:27.120
<v Speaker 1>lives than larger ones. This trend has puzzled veterinary researchers

0:00:27.200 --> 0:00:29.960
<v Speaker 1>for as long as we've been fussing over our faithful

0:00:30.000 --> 0:00:33.480
<v Speaker 1>four legged friends, and it's a mystery that hasn't been

0:00:33.560 --> 0:00:38.800
<v Speaker 1>definitively solved. Conventional wisdom in the animal world dictates that

0:00:38.920 --> 0:00:43.120
<v Speaker 1>between different species, larger animals live longer than smaller ones.

0:00:43.760 --> 0:00:47.120
<v Speaker 1>For example, an elephant can live into its seventies, while

0:00:47.159 --> 0:00:49.360
<v Speaker 1>a mouse might only have a year or two to

0:00:49.640 --> 0:00:53.680
<v Speaker 1>do its earthly business. However, the opposite seems to be

0:00:53.720 --> 0:00:58.000
<v Speaker 1>true within single species subsets, and although dogs come in

0:00:58.080 --> 0:01:01.080
<v Speaker 1>lots of shapes and sizes, they're all the same species.

0:01:01.880 --> 0:01:04.880
<v Speaker 1>The average lifespan for an enormous dog is around seven

0:01:04.959 --> 0:01:07.840
<v Speaker 1>or eight years, while a tiny dog can reliably live

0:01:07.840 --> 0:01:12.440
<v Speaker 1>to the ripe old age of fourteen or fifteen. The

0:01:12.560 --> 0:01:15.680
<v Speaker 1>popular adage that one human year is equal to seven

0:01:15.720 --> 0:01:19.280
<v Speaker 1>dog years isn't supported by modern science. Although it's easy

0:01:19.360 --> 0:01:23.399
<v Speaker 1>math and therefore sticks around. The truth is more complex.

0:01:24.040 --> 0:01:26.160
<v Speaker 1>In the first year of a dog's life, it generally

0:01:26.200 --> 0:01:29.040
<v Speaker 1>reaches the physical maturity of a fifteen year old human.

0:01:29.680 --> 0:01:32.920
<v Speaker 1>The second year adds another nine years, and after that

0:01:33.200 --> 0:01:36.640
<v Speaker 1>the rate of aging varies widely based on breed and size.

0:01:37.520 --> 0:01:40.320
<v Speaker 1>A small dog is considered senior at around age eight,

0:01:40.600 --> 0:01:43.520
<v Speaker 1>while a large dog hits old age around five or six.

0:01:45.040 --> 0:01:48.600
<v Speaker 1>Researchers know this, but they're not entirely sure why, and

0:01:48.760 --> 0:01:51.520
<v Speaker 1>to be fair, it probably involves a combination of a

0:01:51.520 --> 0:01:55.520
<v Speaker 1>lot of different factors. It turns out that a dog's

0:01:55.560 --> 0:01:58.720
<v Speaker 1>size isn't the only, or even the primary factor that

0:01:58.800 --> 0:02:03.000
<v Speaker 1>determines lifespan. Genetics and breeding also play a role, with

0:02:03.080 --> 0:02:06.600
<v Speaker 1>certain breeds being more vulnerable to certain life threatening or

0:02:06.800 --> 0:02:11.480
<v Speaker 1>life shortening diseases and conditions than others. Basically, although the

0:02:11.520 --> 0:02:14.200
<v Speaker 1>aging process for dogs is very different than it is

0:02:14.240 --> 0:02:19.720
<v Speaker 1>for humans, it's also very different. Among dogs. The features

0:02:19.760 --> 0:02:22.000
<v Speaker 1>that a dog has been bred for seemed to matter

0:02:22.160 --> 0:02:25.520
<v Speaker 1>more than size. There was a study published in April

0:02:26.240 --> 0:02:29.200
<v Speaker 1>two in the journal Nature based on a massive database

0:02:29.240 --> 0:02:32.240
<v Speaker 1>of veterinary records from the United Kingdom, and to keep

0:02:32.280 --> 0:02:35.840
<v Speaker 1>it simple, they looked at the lifespans of pure bred dogs.

0:02:35.880 --> 0:02:40.400
<v Speaker 1>Small jack Russell Terriers, and midsized Border collies differ substantially

0:02:40.480 --> 0:02:43.600
<v Speaker 1>in size, but according to the study, they live pretty

0:02:43.639 --> 0:02:48.960
<v Speaker 1>similar lifespans twelve point seven and twelve point one year's respectively. However,

0:02:49.320 --> 0:02:52.919
<v Speaker 1>flat faced breeds like pugs and French bulldogs were found

0:02:52.919 --> 0:02:56.560
<v Speaker 1>to have much lower life expectancies due to breathing problems,

0:02:56.600 --> 0:03:00.240
<v Speaker 1>a disease, and difficulty giving birth. The French bull dogs

0:03:00.280 --> 0:03:03.920
<v Speaker 1>life expectancy is only four point five years, and none

0:03:03.919 --> 0:03:06.320
<v Speaker 1>of the other flat faced breeds, no matter how small,

0:03:06.680 --> 0:03:09.040
<v Speaker 1>were found to have an average lifespan of more than

0:03:09.080 --> 0:03:15.160
<v Speaker 1>seven point eight years. Okay, but why might size matter.

0:03:16.480 --> 0:03:18.880
<v Speaker 1>It might have to do with how long it takes

0:03:18.880 --> 0:03:21.720
<v Speaker 1>a dog to become full grown and the difference in

0:03:21.800 --> 0:03:25.440
<v Speaker 1>size between its puppy body and its adult body. It

0:03:25.560 --> 0:03:29.200
<v Speaker 1>seems that growing very large, very quickly takes time off

0:03:29.280 --> 0:03:33.400
<v Speaker 1>of a dog's overall life span. Take, for example, a

0:03:33.440 --> 0:03:36.320
<v Speaker 1>Great Dane. In the first two years of their life,

0:03:36.360 --> 0:03:39.000
<v Speaker 1>they reach their full size, which can be over thirty

0:03:39.400 --> 0:03:42.320
<v Speaker 1>or eighty centimeters tall, and some a hundred and seventy

0:03:42.320 --> 0:03:45.960
<v Speaker 1>five pounds around eighty kilos. That's a lot, and it

0:03:46.000 --> 0:03:51.040
<v Speaker 1>apparently takes a toll. Large breeds die of cancer more

0:03:51.080 --> 0:03:54.640
<v Speaker 1>often than small breeds, a trend that researchers believe has

0:03:54.680 --> 0:03:56.840
<v Speaker 1>to do with how quickly they grow in their first

0:03:56.920 --> 0:04:00.600
<v Speaker 1>year of life. With all that rapid expansion, it possible

0:04:00.600 --> 0:04:04.040
<v Speaker 1>that abnormal cell growth is more likely, or because their

0:04:04.080 --> 0:04:06.400
<v Speaker 1>lives play up more quickly, that they succumb to the

0:04:06.440 --> 0:04:10.040
<v Speaker 1>diseases of old age earlier than say a chihuahua. It

0:04:10.160 --> 0:04:12.520
<v Speaker 1>takes a chihuahua about ten to twelve months to grow

0:04:12.560 --> 0:04:15.800
<v Speaker 1>to full size, but that size usually maxes out at

0:04:15.840 --> 0:04:19.640
<v Speaker 1>only about eight inches or fifteen centimeters tall and six pounds,

0:04:19.720 --> 0:04:23.200
<v Speaker 1>which is just under three kilos. It's just not as

0:04:23.279 --> 0:04:26.040
<v Speaker 1>taxing on the body to become a full grown chihuahua

0:04:26.279 --> 0:04:30.679
<v Speaker 1>as it is to become a complete great dane. Finally,

0:04:31.000 --> 0:04:35.240
<v Speaker 1>lifestyle and access to veterinary care can affect longevity, and

0:04:35.400 --> 0:04:37.520
<v Speaker 1>these factors can depend on the role of the dog

0:04:37.560 --> 0:04:41.640
<v Speaker 1>within the family. For example, toy dogs may be pampered

0:04:41.680 --> 0:04:46.880
<v Speaker 1>more than larger breeds given their lap friendly size. And

0:04:47.200 --> 0:04:50.040
<v Speaker 1>all of this isn't just important in terms of figuring

0:04:50.040 --> 0:04:52.360
<v Speaker 1>out how we might all spend more time with our

0:04:52.400 --> 0:04:57.000
<v Speaker 1>beloved companions a dog. Research is also important because dogs

0:04:57.040 --> 0:05:00.320
<v Speaker 1>die of the same illnesses that humans do, including answer

0:05:00.480 --> 0:05:04.600
<v Speaker 1>heart disease and diabetes, and so as usual, learning more

0:05:04.640 --> 0:05:12.840
<v Speaker 1>about them may help us learn more about ourselves. Today's

0:05:12.880 --> 0:05:15.240
<v Speaker 1>episode is based on the article the longest living dog

0:05:15.279 --> 0:05:18.120
<v Speaker 1>breeds are tiny, but Why on how stuff works dot Com,

0:05:18.160 --> 0:05:21.200
<v Speaker 1>written by Jesslyn Shields. Brainstuff this production of I Heart

0:05:21.240 --> 0:05:23.360
<v Speaker 1>Radio in partnership with how stuff works dot Com, and

0:05:23.400 --> 0:05:26.440
<v Speaker 1>it's produced by Tyler Clang. For more podcasts, my heart

0:05:26.480 --> 0:05:29.200
<v Speaker 1>Radio is the I heart Radio app, Apple Podcasts, or

0:05:29.240 --> 0:05:30.960
<v Speaker 1>wherever you listen to your favorite shows.