An observation of a severely disabled infant chimpanzee in the wild and her interactions with her mother
We report the physical and behavioral development of one severely disabled female infant chimpanzee (Pan troglodytes schweinfurthii) of the well-habituated M group in the Mahale Mountains National Park. We documented interactions between the infant and its mother and with other group members. Congenital disabilities occur in many primate species, including chimpanzees. However, there have been only a few case studies of congenitally disabled chimpanzee infants and no reports examining how a chimpanzee mother copes with such a disabled infant in the wild. The observed infant exhibited symptoms resembling Down syndrome, similar to those reported previously for a captive chimpanzee. The mother did not allow nonrelatives to take care of the infant even though she had been previously relatively tolerant of allomothering by nonrelatives. The mother’s compensatory care for her infant’s disabilities and allomothering of the infant by its sister might have helped it to survive for 23 months in the wild. Other group members did not show any aversive or fearful reactions to the disabled infant.
KeywordsMahale Mountains National Park Chimpanzee Congenital malformation Mother–infant relationship Disability care Development
We thank the Tanzania Commission for Science and Technology, the Tanzania Wildlife Research Institute, the Tanzania National Parks, and the Mahale–Gombe Wildlife Research Centre for permissions to conduct this research at Mahale; and Tanzanian assistants for their daily help in the field. We thank Mr. T. Udono and Dr. M. Fujisawa for valuable comments on symptoms of XT11 by checking the photos. This research was financially supported by the Grants-in-Aid for Scientific Research (#21730593 to S. Inoue and #24255010 to J. Yamagiwa) and the Grants-in-Aid for JSPS Fellows (#14J00562 to T. Matsumoto).
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