Variability of weaning age in mountain gorillas (Gorilla beringei beringei)

Mountain gorillas (Gorilla beringei beringei) in Bwindi Impenetrable National Park, Uganda, are weaned at a significantly later age than their counterparts in the Virunga Volcanoes, averaging 57.5 months, more than a year longer than Virunga gorillas. This study, analyzing data from four gorilla groups, found that sons were weaned later than daughters, while maternal parity and dominance rank did not influence weaning age. Bwindi mothers often resumed mating while still suckling their infants and conceived before weaning their previous offspring, with no significant difference in the time to conception after resumption of mating compared to Virunga gorillas. These findings highlight the impact of ecological conditions on life history patterns, offering insights into the evolution of human-like reproductive strategies.

Robbins, M. M., & Robbins, A. M. (2021). Variability of weaning age in mountain gorillas (Gorilla beringei beringei). American Journal of Physical Anthropology, 174(4), 776–784. Portico. https://doi.org/10.1002/ajpa.24237