Why Females Live Longer Than Males: Insights from Animal Studies

Females whether human or other mammals like primates or whales, tend to outlive males by an average of 5.4 years. A recent study suggests this isn’t a coincidence. The difference in lifespan between males and females appears to be embedded in genetic and social structures across animal species.

The Study

Published in Science Advances and led by primatologist Johanna Stärk, the research analyzed lifespan data from over 1,100 species of mammals and birds, both in the wild and in zoos. Key findings include:

• In approximately 72% of mammal species, females lived 12% longer than males.
• Interestingly, in birds, the trend was reversed: in 68% of species, males lived about 5% longer than females.

The Role of Genetics

Chromosomes may partly explain these differences:

• Mammals: Males are heterogametic (XY), while females have a matching pair (XX).
• Birds: Females are heterogametic (ZW), while males have a matching pair (ZZ).
  Across both groups, the heterogametic sex tends to have shorter lifespans.

Environmental and Behavioral Factors

Lifespan differences are not solely genetic:

• Even in zoos, where competition for resources is minimal, sex-based lifespan differences persist.
• In the wild, the gap is wider due to competition and parenting roles.

Additional patterns include:

• Species where males fight more tend to have shorter-lived males.
• In monogamous species (especially birds), the lifespan gap is smaller or can even reverse.
• Species where one sex invests more in child-rearing (usually females) often see longer lifespans in that sex. Evolution seems to reward parental effort, while “deadbeat” parents don’t benefit as much.

Why Females Often Outlive Males

• Females live longer: Across mammals, females outlive males by about 5.4 years on average.
• Mammals vs. birds: In 72% of mammal species, females live longer; in 68% of bird species, males live slightly longer.
• Genetics matters: The heterogametic sex (XY in mammals, ZW in birds) tends to die sooner.
• Behavior counts: Fighting males, parenting roles, and monogamy influence lifespan gaps.
• Evolution rules: Life expectancy is shaped more by social structure and evolution than just diet or exercise

Author: Master Vikrant RohinMaster Vikrant Rohin is an international author, and more than four countries’ schools are using his books in the core curriculum of education. He is the author of twenty different subject books. History, Economics, Chemistry, Physics, English, Biology, Geography etc. Most of his students hold high-ranking positions in the public and private sectors. He has cracked the world’s toughest exam, the "Civil Services Examination (UPSC)," eight times. Always a topper in academics, he was also a top-class sportsman, a state boxer, and a basketball player.