We May Have Solved the Mystery Why Human Life Is Only About 80 Years
Have you wondered what causes the average human to die at 80?
Many marine animals make our average life expectancy of 80 years seem like a really bad deal.
Bowhead whales can live more than 200 years. The Rougheye rockfish has a maximum life expectancy of at least 205 years, and Greenland sharks are estimated to live at least 272 years.
On the other hand, mice and other small creatures can expect to die after only a few years.
Nature seems to have rolled the dice on how long who gets to enjoy their existence.
We’ve dreamed of immortality since the dawn of time.
For a long time, researchers have been searching for clues as to why some animals live so much longer than others to find the key to longevity.
There’s been much speculation that it depends on the size. Experts suggested that smaller animals use energy faster, requiring faster cell turnover, which causes more rapid decay.
But there’s no clear pattern there. A five-inch naked mole rat can live 25 years, as can a much larger giraffe, which lives an average of 24 years.
If it’s not size that matters, what does?
A new study from the Wellcome Sanger Institute published in Nature suggests that the rate of genetic damage may be the key.
Genetic changes, called somatic mutations, occur in all cells and are mostly harmless. The body repairs or ignores them.
But some can put a cell on the path to cancer. These cells mutate in a way the body can’t repair.
What’s new here is that even if mutations don’t cause cancer, they accumulate. They cause the body to shut down and die after a certain point.
Dr. Alex Cagan, first author of the study, said:
“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…