Scientists finally managed to find something. why explanation dogs larger ones have a shorter lifespan than smaller ones. According to the results, selective breeding on the basis of height,Large breeds are more susceptible to cancer.
Experts from the University of Adelaide (Australia) have developed a study plan to find the reasons for the differences in life expectancy in 164 dog breeds, from Chihuahuas to Great Danes.
dogs on average large breeds usually live 8 to 10 years, while small breeds reach 15 years of age. and in some cases closer to 20, according to experts.
“When we analyzed these datasets, we found that larger dogs were more likely to die of cancer at younger age “Compared to smaller dogs,” said Jack da Silva of the University of Adelaide’s School of Biological Sciences.
“Larger dogs didn’t have to age faster than smaller breeds.But studies have shown that as the average body weight of the breed increases, so do cancer rates.”
“The relationship between a dog’s body size and life expectancy may be due to an evolutionary delay in the body’s defense against cancerUnable to keep up with the rapid and recently selective breeding of larger dogs”, according to this researcher.
Research published in the journal American Naturalistfound that shorter life expectancy is consistent with a theory of aging known as life history optimization, or “disposable soma.”
Or grow or prepare defenses
“This theory is based on the idea that, If you invest most of your resources and energy in growth and reproduction, you cannot invest them in cell repair and defense against cancer.. In all organisms, the focus is on early reproduction, even at the expense of maintaining and repairing the body and living longer,” said da Silva.
He noted that the results could also be useful for studying aging in humans.
“Dogs make a good model for studying aging in humans. Dogs, like humans living in the industrialized world, live in an environment that tends to protect them from accidental and contagious causes of death, and therefore more likely to die from age-related diseases such as cancer‘, says the researcher.
Although the results of this study are of concern among large dog owners, The researchers predict that larger breeds will gradually evolve to develop genes that fight cancer better.
“Most of the 400 or so dog breeds we know today have emerged in the last 200 years. Larger dogs have not had time to develop better cancer defense mechanisms to match their size.. That could still happen, but at the expense of reproduction,” da Silva explained.
the teacher guesses larger breeds will adapt and prolong their lifespan, but according to aging theory they are more likely to have smaller offspring in the future.
“This can happen naturally or through selective breeding, breeding large dogs that have lower cancer rates and therefore longer lifespans,” he said.
This research was the result of a one-year comparative analysis study using published data on dog breeds from around the world.
Professor da Silva is currently investigating the link between litter size, cancer rates and life expectancy in dogs and other mammals.
Reference work: https://www.journals.uchicago.edu/doi/10.1086/724384
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