Abstract
Social relations of 2 male (6 and 9 years old) and one female (9 years old) chimpanzee orphans were compared with those of non-orphans of similar age and sex. Each orphan lost its mother at the age of 5, 7, and 7 respectively. Two orphans, a 5-year-old male, and a 9-year-old female, spent more time alone, and were groomed less, than their non-orphan counterparts. The 9-year-old male orphan, however, did not differ from his counterparts in terms of both time spent alone and frequency of being groomed. The age-sex class of the orphans' closest associates depended on their age-sex class and on the availability of siblings. All the orphans “met” with a larger number of group members than their respective counterparts. Although the sample size is small, the loss of mothers appeared to facilitate, rather than retard, the sociability of young orphan chimpanzees in this study. A special case of the behavior of a 4-year-old female infant, who lost her mother at the early age of 3 was also described.
