Gorillas are the largest of the great apes, and among the world’s most enᴅᴀɴɢᴇʀed species. Mountain gorillas are the largest living primate and display extreme size differences between the sᴇxes. Males weigh around twice as much as females and can tip the scales at around 44lbs (200 kilos). Mountain gorillas have been widely studied in the wild since the 1950s and many factors have contributed to their enᴅᴀɴɢᴇʀed status, including habitat loss, ᴘᴏᴀᴄʜing and snares meant for small game.
Lately, a study has found that female gorillas that sit at the top of the social ladder have more reproductive success than their peers.
Scientists studying 34 female mountain gorillas in Rwanda discovered that high ranking females have babies more frequently, probably due to more access to males.
Unlike male gorillas, body size and the subsequent advantage in fighting has no impact on which females are the most dominant in a group.
Researchers assessed daily behaviours of the females in Volcanoes National Park to determine which females had the highest social rank.
Lead author Dr Edward Wright, a primatologist at the the Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany, said: ‘High-ranking females produced offspring more frequently, perhaps as a result of preferential access to males.
“Very few studies have examined the inter-relationship among body size, dominance rank and reproductive success together. Higher-ranking female gorillas had significantly shorter inter-birth intervals than lower ranking ones – which is a proxy for reproductive success. It was really interesting to find neither of these variables significantly correlated with body size.”
They then compared this with body measurements to see if rank was correlated to body size.
They found that, unlike males who achieve power thanks to wide backs and ʙʀᴜᴛᴇ ꜰᴏʀᴄᴇ, female gorillas reach a high status thanks to age or group tenure.