Group size and structure in western lowland gorillas (Gorilla gorilla gorilla) at Mbeli Bai, Republic of Congo

Am J Primatol. 2002 Apr;56(4):193-206. doi: 10.1002/ajp.1074.


This paper describes the size and structure of western lowland gorilla groups visiting Mbeli Bai, a swampy forest clearing in northern Congo. An observation platform at the edge of the clearing was used over a 3-yr period, with gorillas visible for 1,681 hr. Data are presented on 14 groups and seven solitary males. Mean group size (excluding solitary males) was 8.4 +/- SD 4.3, and did not differ significantly from most other gorilla studies. All groups at Mbeli contained only one fully mature male and did not show evidence of fission-fusion or regular subgrouping. All emigrating males that remained in the population became solitary, and "bachelor" groups were not observed. Methodological issues are raised, including the classification of multi-male groups, and the demographic profiles of other populations are discussed in the light of results from Mbeli.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Demography
  • Female
  • Gorilla gorilla*
  • Male
  • Population Dynamics
  • Social Behavior*
  • Trees