Gorillas are arboreal apes

Gorillas, long perceived as primarily terrestrial apes, are far more arboreal than previously believed. A study comparing frugivorous populations of mountain gorillas (Gorilla beringei beringei) in Bwindi Impenetrable National Park, Uganda, and western gorillas (Gorilla gorilla gorilla) in Loango National Park, Gabon, found that both groups spent significantly more time in trees than the Virunga mountain gorillas. Adult females in these populations were 21% and 34% arboreal, respectively, compared to just 7% for Virunga gorillas, while adult males were 18.1% and 18.6% arboreal versus 2%. The research challenges the assumption that gorilla arboreality is solely driven by fruit consumption or limited by body size, revealing that nearly half of Loango gorilla fruit-eating occurred on the ground and most arboreal feeding involved non-fruit items like leaves. These findings reshape our understanding of gorilla ecomorphology and have implications for interpreting fossil ape evolution.

Robbins, M. M., Drummond-Clarke, R. C., Robbins, A. M., Ostrofsky, K. R., & Kivell, T. L. (2025). Gorillas are arboreal apes. Current Biology, 35(12), 2974–2979. https://doi.org/10.1016/j.cub.2025.05.015