Overview

• Female gorillas preferentially join groups containing females they co-resided with for at least five years and encountered within the last two years.
• Female gorillas avoid groups containing males they grew up with to reduce inbreeding risk when parentage cannot be confirmed.
• Broad group characteristics such as overall size and sex ratio do not affect female dispersal decisions.
• The findings underscore how more than 20 years of continuous behavioral observations by the Dian Fossey Gorilla Fund enabled detection of nuanced social strategies.
• Researchers note that these intergroup bonds parallel human social mobility and may illuminate the evolution of larger cooperative societies.