A large ape with black fur that travels through forests in groups.
Mature males develop grey hair on the back and are called silverbacks.
Male mountain gorillas, a subspecies of the eastern gorilla, rapidly beat their chests with slightly cupped hands. The resonant sound accompanies the movements of an upright body. In Rwanda’s Volcanoes National Park, males with broader backs produced chest beats with lower peak frequencies.
Acoustic analyses used 36 chest-beating sequences recorded from six adult males in two groups between November 2015 and July 2016. Researchers measured back breadth across the shoulders from calibrated photographs, including the rounded arms. They accounted for age and repeated recordings of the same individuals when testing the relationship between size and sound.
Body breadth was associated with the frequency of the sound, whereas bout duration and the number of beats were not significantly associated with size. The authors proposed that the lower resonance could provide distant listeners with information about the sender’s size. The resonance of a large body accompanies the male’s visible display.
An extinction-risk assessment has not been added yet.
Mountain gorillas in the Virunga region have received continuous daytime monitoring and veterinary care. A 2011 paper examining demographic records from 1967–2008 reported 42 interventions for snare wounds; all but one of the treated individuals survived. The authors recommended strengthening antipoaching patrols and rules governing research and tourist visits, to reduce the risk of introducing human pathogens.