Human beings live far longer than most other mammals. Dogs can survive for about twelve years, while cats may live up to fifteen years. Hamsters only live a few years, whereas blue whales, the world’s biggest mammal, may survive up to one hundred and ten years – that’s what the oldest blue whale on record died at age 110.
So, why do humans live longer than most other animals, on average reaching the age of eighty? Finally, a solution to this long-standing issue has been discovered by scientists.
The distinction between the two has to do with something that both humans and animals have in common. All mammal species appear to succumb to a similar number of genetic changes, suggesting that this DNA damage might be what determines how long an organism survives on Earth.
For many years, scientists maintained that the size of an animal determined how long it lived. Rats and mice live shorter lives than elephants and other large ocean creatures like whales. However, according to a new study, it is not the species’ dimensions that count but rather the number of gene mutations it has acquired over time.
The latest research was carried out by scientists at the Wellcome Sanger Institute in Cambridge, UK. They discovered that larger animals may successfully slow down the rate at which their genetic faults develop, allowing them to live longer than many tiny mammals. Animals who survive longer have the potential to limit the amount of time their bodies’ cells are damaged as a result of gene mutations that occur over time.
According to this new research, five-inch naked mole rats can live for twenty-five years due to their inherent ability to reduce cell damage over time. This is a very long lifespan considering the size of these mammals. The average lifespan of a naked mole-rat is longer than that of a giraffe, which typically lives for twenty-four years. To understand why this might be, scientists looked at the number of gene mutations these two species have and found them to be relatively close. Giraffes suffer from ninety-nine gene mutations per year on average, while naked mole rats have around ninety-three.
Meanwhile, mice have approximately 796 gene mutations each year, whereas humans, who live an average of 83 years and have far fewer annual gene changes at around forty-seven per year, are in a completely different league.
Many gene mutations are inconsequential. However, some can cause cell damage and lead to cancer and other diseases that impair normal functioning and reduce the survival rate.
According to Dr. Alex Cagan, the study’s lead author: “To find a similar pattern of genetic changes in animals as different from one another as a mouse and a tiger was surprising. But the most exciting aspect of the study has to be finding that lifespan is inversely proportional to the somatic mutation rate. This suggests that somatic mutations may play a role in aging.”
