A new study analyzed over a thousand animal species and found that there is usually a correlation between living longer and having two identical chromosomes.
It is a trend observed in different cultures and periods and even in many animal species – women live longer than men. Now, a new published in Science Advances suggests that the explanation may be rooted in evolutionary historywith sex chromosomes and reproductive strategies to play fundamental roles.
The investigation examined data from 1176 species of mammals and birds who live in zoos. It is the most comprehensive analysis of life expectancy differences based on sex in these groups to date.
The results revealed an impressive contrast: mammalian females live an average of 12% more than maleswhile males survive females by about 5%. This is in line with the hypothesis of heterogeetic sex, which proposes that sex with two identical chromosomes It has an advantage of survival. In mammals, females carry two X chromosomes, while males have an X and one Y. In birds, the pattern is reverse: females are heterogametic sex with ZW chromosomes, while males carry two Z chromosomes.
Still, the Chromosomes do not tell the whole story. “Some species have presented the opposite of the expected standard,” explained lead author Johanna Stärk. For example, in many birds of prey, females are larger and live longer than males.
To further investigate, researchers examined reproductive strategies and found that the Polygos mammals With intense male competition they tended to have a shorter life expectancy. Birds, on the other hand, are more often monogamous and face less reproductive competition, helping males gain an advantage in longevity.
Parental papers also matter. In species where a sex invests more in the creation of the offspringusually females between mammals, this sex tends to live longer. For long -lived animals, such as primates, prolonged female survival ensures that puffs grow to independence, reinforcing the survival of the species, explains the.
The fact that the study was centered on zoo animals also clarifies biology behind this gap. Captive Removes many stress factors External, such as predation, food scarcity or rigorous climates. Still, the same sex -based standards persisted, suggesting that intrinsic biological factors are in action.
Researchers say results help explain why women consistently survive longer than men in all human societies, even with medicine and improving living conditions to decrease this difference.
“The greatest life expectancy for women seems to be a feature rooted in our evolutionary history”Concluded the team.
