M. Nakamichi et E. Kato, Long-term proximity, relationships in a captive social group of western lowland gorillas (Gorilla gorilla gorilla), ZOO BIOL, 20(3), 2001, pp. 197-209
To visualize long-term social relationships among 12 gorillas in a captive
breeding group at the San Diego Wild Animal Park, San Diego, CA, the multid
imensional scaling (MDS) procedure was applied to proximity (within 5 m) va
lues collected in five different periods over 2.5 years. The resulting two-
dimensional representations clearly show that in samples taken during this
2.5-year period, the silverback male was surrounded by five adult females,
while three infant or young juvenile females, gathered in a body, remained
between the silverback male and adult females. Some adult females maintaine
d proximity to the silverback male more frequently than other adult females
throughout the five periods. Unlike mountain gorillas in the wild, females
with dependent offspring did not tend to stay near the silverback male mor
e frequently than other females, and related females did not tend to spend
more time near each other than non-related females. Three older juvenile or
young adult males were plotted the furthest from the silverback male, with
gradual changes with increasing age. The usefulness of the MDS procedure,
which can be used to visualize easily and clearly the social relationships
among individuals, is discussed from the viewpoint of the management of bre
eding groups of captive gorillas. (C) 2001 Wiley-Liss, Inc.