Abstract
Effects of the arrival of a younger sibling on the first-born was examined to investigate the attachment of a captive infant chimpanzee (Pan troglodytes). The subject was a first-born female infant chimpanzee that had been reared artificially from two months. Each response of the subject was observed and video-recorded in conditions where the mother cared for the sibling, the mother cared for a pig toy, or a stranger cared for the sibling. The results showed that the subject was especially likely to protest the mother-sibling interaction. It seems that the subject was to recover mother's attention by taking part in the mother-sibling interaction. These results clearly showed that the attachment of an infant chimpanzee was similar to that of human infants.
