2009 年 117 巻 2 号 p. 113-119
The quantitative and demographic features of infant-corpse-carrying behavior in Japanese macaques (Macaca fuscata) at Takasakiyama, southern Japan, have been studied over 24 years. More than 91% of the dead infants that were carried by their mothers were abandoned within a week. Mothers of all age classes exhibited this behavior and neither the carrying rate (number of carriers/number of deaths) nor the duration were significantly different between young and older mothers. The sex of the infant was not a decisive factor. Nearly 80% of all cases observed involved infants that had died within 30 days of birth. The oldest infant whose corpse was observed being carried had died at 253 days. The overall carrying rate was 15% when death had occurred within 253 days and 28.7% for infants that died within 30 days of birth. Most mothers whose infants had lived for more than a month abandoned the corpse soon after death. Some females persist in exhibiting behaviors performed towards live infants but the exact reasons for this are unclear at present.