Contrary to popular belief, small dogs have a much longer life expectancy than their large counterparts.A team of researchers from the University ofGöttingen, in Germany, set out to find why this was true. In a study, published in the reviewThe American Naturalist, they analyzed the correlation between lifespan and size in canines.
Source : Pets4home
Despite their apparent fragility, little dogs live several years longer than large breeds, but what is more surprising is that for every extra kilogram a dog carries, his life expectancy diminished by approximately two weeks.A German shepherd that weighs 70kg would only live for around 7 years, in contrast to a 5kg pup living for 14 years...Cornelia Kraus, a biologist at the University ofGöttingen, confirmed:
This tradeoff has been known about for a long time, but nobody has yet investigated the underlying demographic mechanism.
Source : Officialhuskylovers
The research team came up with two hypotheses - one suggests that the process of aging in big dogs happens more rapidly, and the other suggests that because of this quick aging, big dogs are prone to diseases which decrease their lifespan. Finally, according to a third hypothesis, big dogs simply have a larger risk of mortality throughout the course of their lives.Kraus and her team analyzed numerous demographic data obtained from American veterinary clinics, which gave information about the age and cause of death of nearly 50 000 dogs spanning 74 different breeds.The three aforementioned hypotheses were tested on each subject and "mortality curves" were drawn up - charts that show mortality risk plotted against age.The curve which predicted that big dogs age quicker and die sooner was the most accurate one when the data from the clinics was counted. "That's where we really see a strong correlation," Kraus confirmed. In more simple language, other team members said, "their adult life unwinds in fast motion."
Source : Mymodernmet
The question still remains as to why big dogs age more rapidly than small ones. Certain studies claim it could be linked to hormones. The hormone IGF-1, referring to the growth hormone, is present in smaller quantities in the blood of small dog breeds.In larger mammals, humans included, with a high mortality rate, there is a strong presence of IGF-1, linked to age-related diseases such as cancer or heart attacks.This study is the beginning of the peeling back of many layers into this question and could mean more insight into the development of medicines that would help our pups to live longer lives.
H/t: InsideScience
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