ABSTRACT
This chapter outlines the personal observations on the ecology and social life of the mountain gorilla (Gorilla gorilla beringei), and to a lesser extent on the chimpanzee (Pan troglodytes schweinfurthii) and orangutan (Pongo pygmaeus), as a basis for some comments on hominid origins and social behavior. The gorilla data are based on a six-month ecological and distributional survey in the eastern Congo and Uganda from February to July, 1959, followed by fifteen months of intensive field work by Schaller in selected localities. The detailed observations on social behavior were made on a population of ten groups in an undisturbed section of the Virunga Volcanoes of Albert National Park, Congo, unless otherwise stated. Even though the climate and vegetation vary from distinctly tropical in the Congo basin to temperate in the mountains, the habitats utilized by gorillas are similar in being lush and damp with an abundance of food in the form of vines, leaves, bark, pith, and some fruits.
