Variability of weaning age in mountain gorillas ( <i>Gorilla beringei beringei</i> )

Objectives Weaning is a key life history milestone for mammals that represents both the end of nutritional investment from perspective mothers and start complete independence infants. The age at weaning may vary depending on ecological, social, demographic factors experienced by mother infant. Bwindi mountain gorillas live in different environmental conditions have longer interbirth intervals than their counterparts Virunga Volcanoes, yet other characteristics this population remain less well known. We use long-term data Impenetrable National Park, Uganda to examine related age. Materials methods analyzed infants born four gorilla groups quantify (defined as last nipple contact) test if sex offspring, parity, dominance rank influences weaning. also compared time conception after resumption mating gorillas. Results were weaned an average 57.5 months. No difference was found between primiparous multiparous mothers, nor did maternal influence weaning, but sons later daughters. majority still suckling when they resumed generally conceived before previous offspring. significantly After mating, conceiving next offspring not females Virungas (6 vs. 4 months). Discussion Later daughters similar findings studies great apes. are approximately same western chimpanzees, which more year results study suggest variation ecological populations living close geographic proximity can result patterns, has implications understanding evolution unique patterns humans.