Comparison of bonobo anatomy to humans offers evolutionary clues

Jun 4, 2015

by Bob Yirka

A pair of anthropology researchers, one with the University of California, the other Modesto College has found what they believe are clues to human evolutionary development by conducting a long term study of bonobo anatomy. In their paper published in Proceedings of the National Academy of Sciences, Adrienne Zihlman and Debra Bolter, describe their anatomy studies and their ideas on why what they found offers new clues on why humans developed in the ways we did.

Scientists looking to understand how humans evolved have studied a lot of fossils, but such samples are of bones, which means there is little to no evidence of what organs, muscle or fat looked like in our ancestors which means there are still questions regarding things such as what percentage or proportion of fat or muscle was there, where were they located on the body, and what the organs were like. In this new study, the research pair sought to uncover clues by studying bonobos, apes that look a lot like chimpanzees and are considered to be our closest relative.

To learn more about bonobo , the researchers performed autopsies on thirteen of the apes that had died naturally over the course of three decades, carefully jotting down seldom noted information such as fat and muscle percentages. In so doing, they came to see that bonobos have considerably less fat on their bodies than do humans, even those that lived a similar sedentary life due to living in captivity. They also found that the apes had more upper body mass than humans as a rule and less leg muscle—bonobos also have a lot more skin.

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8 comments on “Comparison of bonobo anatomy to humans offers evolutionary clues

  • I think the green bars indicate upper body musculature, and the plum bars indicate lower body musculature. Ideally you would want to measure live healthy specimens. Dead humans are often emaciated.

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  • One interesting difference between the male dominated Chimp (Pan) groups, and the female dominated Bonobo groups, is in the dominant male chimps.

    Adult male chimps are heavier than the females and youngsters, so are more limited in the size of tree branches which will support their weight. This is a handicap when looking for sleeping nesting areas, or reaching food, but as compensation, allows them to dominate other chips in the group.

    Unlike humans, chimps usually walk on all fours when on the ground, but can walk on two legs.

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  • I can probably walk as well on all fours as a chimp can walk on two?
    Actually whats interesting to me is that we can see that homo species devote far more bodily resources to building powerful legs which allowed early hominids to be distance hunters that ran down their prey.
    Another point is that we are the evolutionary result of earlier hominids using tools which made powerful arm muscles less necessary ie the use of weapons to hunt and tools to dig up roots and the like.

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  • Apparently there is evidence of evolutionary memes in our primate relatives!
    Chimpanzees found to drink alcoholic plant sap in wild

    They have shown an understanding of language and a sense of fairness, and now humans’ closest primate cousins have even been found to share a taste for alcohol.

    Scientists studying chimpanzees in Guinea have seen evidence of long-term and recurrent ingestion of ethanol by apes.

    The 17-year study recorded chimps using leaves to drink fermented palm sap.

    Some drank enough alcohol to produce “visible signs of inebriation”.

    The study – published in the journal Royal Society Open Science – revealed their tipple of choice is naturally fermented palm wine, produced by raffia palm trees.

    In the Bossou area of Guinea, where this research took place, some local people harvest “palm wine” from the trees – tapping them at the crown, and gathering the sap in plastic containers, which they collect in the mornings and evenings.

    Researchers working in the area had already witnessed chimpanzees climbing the trees – often in groups – and drinking the naturally fermented palm sap.

    The chimps used drinking tools called leaf sponges – handfuls of leaves that they chew and crush into absorbent sponges, dip into the liquid and suck out the contents.

    A drink of palm wine with a cousin anyone??

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