The western gorilla is the largest living primate, inhabiting tropical forests of West-Central Africa (Cameroon, Gabon, Congo, etc.). Adult males (silverbacks) can reach 140–200 kg and stand ~170 cm; females are about half that weight. They have brownish-black fur; mature males develop a silver saddle on the back. The face is bare, black, with a broad nose and prominent brow ridge. Males also have a pronounced sagittal crest for jaw muscle attachment. Western gorillas are primarily herbivorous, eating leaves, stems, fruits (more frugivorous than eastern gorillas), bark, and occasionally ants and termites. They live in stable groups of 5–30 led by a dominant silverback who protects the group and mediates conflicts. They are predominantly terrestrial knuckle-walkers. Females reach maturity around age 10 and have a gestation of ~8.5 months, usually one infant. Inter-birth interval is 4–6 years. Lifespan is 35–40 years in the wild. The species is Critically Endangered due to Ebola outbreaks, poaching, and logging.