Caring for disabled children has been thought to be a definitive human behavior, but new evidence suggests that chimpanzees care for disabled children as well. Takuya Matsumoto and colleagues from Kyoto University in Japan are the first to report long-term care for a disabled infant by a chimpanzee mother and the infant’s sister.
The infant chimpanzee was born with a condition that resembled Down syndrome. The infant’s legs did not have the strength to clasp its mother firmly enough to be supported during feeding or travel. The researchers observed the mother and the disabled infant’s sister supporting the disabled chimpanzee so that it could feed and be transported to different nesting areas. The behavior continued for 23 months in Tanzania’s Mahale Mountains National Park. Female chimpanzees that were not related to the disabled child were prevented from assisting in caring for the disabled infant by the mother even when the other chimps offered assistance.
The study shows that caring for disabled children is not solely a human behavior. The behavior can be attributed to simple mothering instincts. Chimpanzees are some of the most intelligent apes and have been shown to have behaviors that were once considered to be only a human attribute. No methods of determining brain functions in the mother were used so it is not possible to confirm or deny the existence of compassion in one of man’s closest relatives. The potential does exist that compassion for the disabled evolved much earlier than modern man.
