Overview

• The Science Advances analysis pooled longevity records for 1,176 species across wild and captive populations.
• Females outlived males in 72% of mammals by about 13% on average, whereas males lived longer in 68% of birds by roughly 5%.
• Findings align with the heterogametic-sex hypothesis, in which the homogametic sex (XX in mammals, ZZ in birds) typically gains a longevity edge.
• Stronger male competition in polygamous systems correlated with higher male mortality, while monogamy or shared care tended to narrow the gap.
• Gaps were smaller yet persistent in captivity, and the human female advantage in lifespan is framed as part of this broader evolutionary pattern.