Overview

• An international Max Planck–led team published the analysis in Science Advances on Oct. 1, using records for 1,176 zoo-kept mammal and bird species.
• Females outlived males in most mammals (72%), by about 12% on average.
• Males lived longer in most birds (68%), by roughly 5% on average, with notable exceptions such as many raptors.
• Findings support the heterogametic sex hypothesis and link larger gaps to polygamy, male competition, and which sex provides more parental care.
• Lifespan differences shrank but persisted in zoos compared with the wild, indicating intrinsic, evolutionary roots.