In first, Japanese researchers observe chimp mother, sister caring for disabled infant

by

Staff Writer

A Japanese study of a chimpanzee mother caring for her disabled infant in the wild has shed light on how humans developed their social behavior.

The first-of-its-kind study by a team of Kyoto University researchers was published Monday in the online edition of Primates, an international journal of primatology.

Born in January 2011 in a chimpanzee group in Tanzania’s Mahale Mountains National Park, the female infant was “severely disabled,” exhibiting “symptoms resembling Down syndrome,” according to a summary of the team’s findings.

The researchers said there have been only a few case studies of congenitally disabled chimpanzee infants and no reports examining how a chimpanzee mother in the wild copes with a disabled infant.

Michio Nakamura, an associate professor at Kyoto University’s Wildlife Research Center who was involved in the study, told The Japan Times on Tuesday that the research could help solve the riddle of how humans evolved into social animals.

“One characteristic of human society is that people reasonably take care of the disabled and those in vulnerable positions,” Nakamura said. “It’s interesting to observe a chimpanzee looking after a disabled infant in terms of finding out when such sociality occurs, as they are the closest modern species to humans.”

Nakamura noted the infant chimpanzee exhibited what appeared to be several disabilities, including a lump on her belly, apparent damage to her spine and hyperdactylism in the form of a sixth finger on her left hand.

“Besides that, she had a fish look and kept her mouth half-open, so we assumed she had some kind of mental handicap,” Nakamura said.

Moreover, he said the infant was unable to sit up on her own and couldn’t latch on to her mother with her feet due to her disabilities.

Despite such physical handicaps, the infant survived for about two years thanks to care provided to her by her mother and an elder sister, Nakamura said.

“It is arguably difficult for severely disabled infant chimpanzees who are not able to walk on their own to survive,” he said.

According to Nakamura, it was mainly the mother that cared for the infant.

“The mother scooped the infant up and carried her when moving since she would drop without help,” he noted. “When breast-feeding, the mother raised the infant to her nipple to feed her.”

As for the elder sister’s role, she looked out for the little sister while their mother ate, Nakamura said.

“It’s quite interesting that the elder sister had a role in caring for the infant,” he added. “It would be a huge burden for the mother to look after the infant without the sister’s help.”

Nakamura said the infant has not been observed since December 2012, prompting the team to conclude that she has died.

He said the infant’s death may be linked to her sister’s pregnancy. The sister gave birth in November 2012, making it difficult to continue helping the mother care for the disabled infant.

Nakamura also said the infant could have died from malnutrition since it was not observed eating solid food. Chimpanzees around her age gradually begin to eat fruit and leaves.

  • mickrussom

    In other news today, chimpanzees will rip your face off and they will throw feces at people and each other in dominance displays. These are wild animals. Its normal for animals that care for their young to be protective of them. People trying to anthropomorphise them are playing a dangerous game.

    • http://webplatformdaily.org Šime Vidas

      Hahaha, as if humans were better.

      • Kazzizzi bazzizzi

        ooh youre so edgy

    • Adam

      Are you just saying this in general because people sometimes don’t appropriately understand or interact with chimpanzees? Or are you implying that the research group or the journalist here is doing something wrong?

    • RexRock

      So actually they are more close to humans then the article will have use believe. Interesting.

    • RexRock

      So actually they are more close to humans then the article will have use believe. Interesting.

    • Prosdod

      Denying the existence of “human” characteristics such as altruism and compassion in animals is incredibly ignorant.

    • Leon

      News flash: a human raised by chimpanzees would probably try to rip your face off as well. Don’t get me started on the goddamn displays of dominance modern humans have developed. Just an advanced s**t throwing contest sometimes.

      Also, it’s completely abnormal for animals to be protective to this degree; to the point where this completely helpless creature reached the age of two. Almost unheard of I’d say. I don’t know if the whole ‘anthropomorphise’ thing suggests you’re not down with evolution, in which case this response will be a complete waste of time, though it would explain why you don’t know that leaving the weakest behind is the general law of the jungle. But as shown here, when these chimpanzees were in an environment where they could afford to sacrifice for their weakest, they did so until their evolutionary limitations rendered them incapable. Very interesting insight into how early along our species began to exhibit this kind of behaviour, and also handy for helping figure out the conditions which allowed it to occur.

    • AJ

      You’re missing the point.
      Evolution dictates that the weak don’t survive- it costs energy to take care of
      an animal other than yourself, and there is no extrinsic benefit to do so for
      an animal that is unable benefit the group and would otherwise be a constant “burden”
      to their own survivability. This shows that chimpanzees are able to recognize a
      potential benefit in doing so, the same as us. These chimps (like humans)
      display a willingness to help others in their in-group, despite the potential
      danger it threatens to their own survive ability. Our altruism and compassion,
      along with parental “love” is something we potentially share with chimpanzees.

      • https://www.youtube.com/user/mrbrokenmonkey BrokenMonkey

        Yeah, I’m confused by mick’s comment as well. It’s not like anybody is saying get a chimp as a nanny or something. These type of findings simply come with the territory. Should the researchers and related media not put out this type of information or something?

    • Samaritan

      Assuming animals have emotions is a dangerous game? Oh no, we might end up treating animals with dignity and respect! It’s safer to assume they are emotionless automatons right?

    • affordableweb

      The ones that ripped faces and toss feces suffered mental illness due to being caged by the humans they attacked. These chimps exist in the wild which is very different place.

    • Bryan David Wolfe

      You’re right! Children are going to wander into their local rain forests in hopes of running off with an adopted chimpanzee family, only to realize their mistake mid-way through getting bath-salt zombied by someone they thought they could trust.

    • Alias McCoy

      So dumb. Am I humanizing humans by pointing out that most don’t rape and rip each other apart despite the fact that such things have been known to happen?

    • Shawn Ruby

      you should try to relate with anything which is humanizing it still. such as music, the ethics in a book… it helps you relate to it and empathize with it more. you sound like a child

    • Scott Hodgins

      Genetically, chimpanzees are the closest you can get to humans. They’re born anthropomorphized. Take a human’s complex language and enculturation away and we’d be wild animals too.

    • Scott Hodgins

      Genetically, chimpanzees are the closest you can get to humans. They’re born anthropomorphized. Take a human’s complex language and enculturation away and we’d be wild animals too.

    • Scott Hodgins

      Genetically, chimpanzees are the closest you can get to humans. They’re born anthropomorphized. Take a human’s complex language and enculturation away and we’d be wild animals too.

    • Scott Hodgins

      Genetically, chimpanzees are the closest you can get to humans. They’re born anthropomorphized. Take a human’s complex language and enculturation away and we’d be wild animals too.

    • Scott Hodgins

      Genetically, chimpanzees are the closest you can get to humans. They’re born anthropomorphized. Take a human’s complex language and enculturation away and we’d be wild animals too.

    • Scott Hodgins

      Genetically, chimpanzees are the closest you can get to humans. They’re born anthropomorphized. Take a human’s complex language and enculturation away and we’d be wild animals too.

    • BridgetD

      What constitutes as “anthropomorphism” is becoming narrower as we learn more about other animals. A chimpanzee isn’t a human isn’t a dolphin isn’t an elephant; every species is unique, and will behave in a unique way, but we have more similarities to one another than it was once thought.

      Yes, chimpanzees can be extremely dangerous; that said, so can humans. I’m not saying that we should invite them to live in our homes, but rather I’m just trying to keep things in perspective.

      Also as AJ said, you’re missing the point. In most species, those born with a disability will not survive; they’re either abandoned by their parents, or even outright killed by them, because it is a costly endeavor to care for the weaker members of a group. This wild chimpanzee was observed caring for her baby, who had been born with multiple disabilities, for two years. This is unusual behavior for a wild animal, even a chimpanzee.

  • Raiden Chu

    That’s so sad. :( I’m glad to reading this article.