Dominy then used a computer to assess, quantify and record the value of each trait to an animal’s fruit selection. advisor, was used to determine the physicochemical attributes of each collected fruit, such as color and firmness.
#CHIMPANZEE HAND AND HUMAN HAND PORTABLE#
When the animals moved on, the scientists climbed the trees to pluck rejected fruits and collect fig pieces from the forest floor.Ī portable field kit designed by Lucas, Dominy’s Ph.D. They did the same with black-and-white colobus monkeys ( Colobus guereza), red colobus monkeys ( Procolobus badius) and red-tailed monkeys ( Cercopithecus ascanius), watching which figs they bit and threw to the ground and which they ate.
They also watched for pieces of fruit that fell inadvertently during eating. They noted which figs the chimps palpated and left on the trees. To conduct their study, he and his team spent many hours a day beneath fig trees watching and videotaping monkeys and chimpanzees foraging in the forest of Uganda’s Kibale National Park. “Palpating a fig adds 73.4 percent more information and reduces ambiguity as to whether it is ripe or not,” Dominy adds.Ĭhimpanzee in Kibale National Park squeezes a fig to test its edibility. If your hands weren’t capable of assessing an avocado by feel, it would take even longer because you would have to bite each one to determine if it was edible. Think of how much longer it takes to select an avocado at the grocery store compared to a banana. Twenty percent of figs show no color change during ripening, which poses a sensory challenge. Ripe figs are almost always available when other fruits are scarce, so animals depend on them at these crucial periods.” “They’re not a particularly high-quality fruit, but in a given area, individual trees ripen at different times.
“Figs are critically important,” Dominy says. It means chimps can forage more efficiently and consume more calories, especially during lean times when preferred foods are unavailable and they are forced to rely on figs. That speed can make all the difference when animals are competing for limited resources, Dominy says. What’s more, squeezing a fig is four times faster than plucking it, biting it and spitting it out if it was not ripe.Ĭhimpanzee in Kibale National Park, Uganda, squeezing a fig to test its ripeness. Monkeys that compete for the same food must rely on color and bite testing, but squeezing figs by chimpanzees supplies nearly 75 percent more information about ripeness than color.
#CHIMPANZEE HAND AND HUMAN HAND MANUAL#
It’s fair for researchers to look at complex hand use among primates and ask if it was a precursor to the manual dexterity that gave rise to modern humans.”īased on field work in Uganda, Dominy and Peter Lucas, researcher at the Smithsonian Tropical Research Institute, who served as one of the study’s co-authors, determined a chimpanzees’ ( Pan troglodytes) ability to feel the ripeness of a fig confers a significant advantage over rival species when selecting fruit. “Hands are a hallmark of human evolution. A surprising omission, he believes, given the importance of hand dexterity and tool use to human development. “We anthropologists have given little thought to why ape hands have greater dexterity than monkey hands,” says Nathaniel Dominy, evolutionary biologist at Dartmouth and lead author of the new study. This video shows a chimpanzee in Uganda evaluating figs (Ficus sansibarica ). Now, a new study published in the journal Interface Focus sheds light on how increased finger dexterity and sensitivity may have benefited the diets of early apes, allowing them a competitive edge in obtaining high-quality food. The additional brain power needed to operate dexterous hands called for a lot of nutritious, high-calorie food as well. Humans stand out as the only hominid with fully opposable thumbs that can turn in toward the palm to touch the tip of each finger.ĭeveloping such complex hands was a costly evolutionary feat, requiring not only anatomical changes to the wrist and fingers, but also expanded nervous tissue to process sensory and motor signals between fingers and brain. One of the primary features that distinguish hominids such as chimpanzees, gorillas and humans from the rest of the animal kingdom are uniquely dexterous hands. A chimpanzee in Kibale National Park, Uganda, bites a fig.
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