TOOLMAKERS AND USERS IN THE ANIMAL KINGDOM
There is some evidence chimpanzees consume plants for medicinal purposes. Chimpanzees generally chew the leaves of the plants they eat. In 1995, researchers observed chimps swallowing leaves of the Aspilia plant whole. Analysis of this plant has found that it contains an oil which eases stomach pain and kills bacteria, fungi and parasites. Swallowing it whole is believed to release the medication in the intestines where the harmful microbes are founds. [National Geographic Earth Almanac, January 1993].
There are many examples of tool-using animals. Egyptian vultures drop stones on ostrich eggs to crack them open; elephants use sticks to rub their backs; chimpanzees and monkeys use rocks to open nuts; sea otters sometimes break open shells with rocks; and gorillas and orangutans use branches to pull down limbs with fruit.
The woodpecker finch uses a twig as a tool with extraordinary skill. First it searches around for a twig that is the right size and strength. Once it finds one it likes it jabs the twig into a hole like a lance and maneuvers it around to pry out grubs deep inside the tree, far beyond reach of its beak. Some finches, once they've found a twig they like, carry it around from tree to tree. According to researchers only about one out of five woodpecker finches have mastered the technique."
In 2001, Betty, a New Caledonian crow kept in the aviary at Oxford University, was the subject of an experiment to find if she would take a straight tool or a hooked one to fetch as tiny bucket with meat inside. When the hooked tool was accidently knocked away Betty took the straight tool and methodically bent it to make a hook which she used to retrieve the bucket.
In December 2009, scientists at Melbourne's Victoria Museum released a photograph of an octopus with its legs wrapped around a coconut shell, which it used to protect itself on the sea floor. The scientists said the octopus carries the shell with it and uses it as armor in what the scientists said was the first known example of an invertebrate using tools.
Websites and Resources on Hominins and Human Origins: Smithsonian Human Origins Program humanorigins.si.edu ; Institute of Human Origins iho.asu.edu ; Becoming Human University of Arizona site becominghuman.org ; Hall of Human Origins American Museum of Natural History amnh.org/exhibitions ; The Bradshaw Foundation bradshawfoundation.com ; Britannica Human Evolution britannica.com ; Human Evolution handprint.com ; University of California Museum of Anthropology ucmp.berkeley.edu; John Hawks' Anthropology Weblog johnhawks.net/ ; New Scientist: Human Evolution newscientist.com/article-topic/human-evolution
Jane Goodall and Tool-Using Chimps
Melissa Hogenboom wrote for the BBC: “It was only when the primatologist Jane Goodall began her studies on wild chimpanzees in the early 1960s that things started to change, albeit slowly. Her mission was to look at chimpanzees in order to understand more about our ancient human ancestors.[Source: Melissa Hogenboom, BBC, July 3, 2015 |::|]
“From the beginning of her time in Africa, she saw strikingly human-like behaviours. In her early research she referred to the chimpanzees as "he" and "she" rather than "it". She also gave them names, something previously unheard of in academia, and began to describe their unique personalities. Tool-use had been considered a uniquely human ability |::|
“She also discovered they ate meat: they were not vegetarians as had been assumed. And to get it they were using tools. She saw chimpanzees fishing for termites with twigs. This in itself was a ground-breaking finding. Until then, tool-use had been considered a uniquely human ability. Her project leader at the time, the paleoanthropologist Louis Leakey said: "Now we must redefine 'tool', redefine 'man', or accept chimpanzees as humans."
Chimpanzees, Tools and Technology Transfer
Chimps have been observed using tools for eating, weaponry and play. Describing the first example of tool manufacturing by a non-human animals, Goodall wrote, "The chimpanzee peers at the surface of a termite heap and, where he spies one of the sealed off entrances, scrapes away the thin layer of soil. Then picks a straw or dried stem of grass and pokes this carefully down the hole. The termites, like miniature bulldogs, bite the straw and hang on grimly as it is gently withdrawn. I have watched chimpanzees fish this way for two hours at a time, picking dainty morsels from the straw and munching with delight. ..I have seen them break off a twig and carry it for a far as half a mile, going from one termite hill to another."
In the forests of northern Sierre Leone chimpanzees have been observed using sticks as "shoes" and "seat cushions" in thorny kapok trees, where the primates often feed on fruit. Chimpanzees in Côte D'Ivoire have been observed using wood hammers to crack open soft nuts and stones to smash open harder ones. When the nuts are in season the sound of hammering chimps is so pronounced that Swiss Researchers Hedwige Boesch-Achermann said "Once I was leading someone here who was wondering what carpenters were doing in the forest." Before the nut is cracked open it is often secured in the knot hole of fallen tree or root protruding from the ground. The chimps prefer to hold the rock with two hands. Stones are scare in the rain forest and chimpanzees place them in different locations around the forest and remember where they are so they can be used again. [Source: Eugene Linden, National Geographic, March 1992 ++]
Tools allow chimps to harvest more nutritious food which outweighs the large body size necessary to carry a larger brain. Nuts are chock filled with calories and with a rock a champ can eat 3,500 calories in just two hours. Consuming the same amount of calories in leaves might take as long as ten hours. ++
Technology transfer has taken place with chimpanzees. The use of twigs to catch carpenter ants was initially observed at only one chimpanzee community in Gombe. When one female moved from one group to another, members of the second groups began using the twig technology. The nut-pounding chimpanzees not only use stones as nutcrackers, remember where they left stones and use them again, mother chimps teach their off spring how to crack nuts.
Chimpanzees adapt to different environment in different ways. Chimps in Tanzania uses sticks to harvest termites but don't use rocks to crack open nuts. For chimps in Côte D'Ivoire the opposite is true. ++
Monkeys in Brazil Make Hominin-Like Stone Tools
tool use by a capuchin monkey
At a national park in Brazil scientists watched Capuchin monkeys smash stones against each other, splitting off sharp-edged flakes that resembled cutting tools early hominins. The monkeys smacked the rocks together, for reasons that aren’t clear, but may involve licking the broken surfaces for silicon, an essential trace nutrient. Sometimes the rocks broke in ways that created flakes or left broken rocks with sharp edges suitable for cutting or scraping. The monkeys didn't use them like that but the researchers wrote that “the production of archaeologically identifiable flakes and cores, as currently defined, is no longer unique to the human lineage.” [Source: Samir S. Patel, Archaeology magazine, January-February 2017]
Associated Press reported: “The monkeys ignored the flakes, focusing on the damaged stones instead. So they clearly weren’t deliberately making them as tools. But if ancient monkeys did the same thing, their unintentional handiwork could be mistaken for deliberate tool-making by human ancestors, researchers said. “The scientists are not suggesting that any stone tools attributed so far to human forerunners were instead made by monkeys, said Tomos Proffitt of Oxford University in England. Those tools, which date back as far as 3.3 million years ago, are more complex than what the Brazilian monkeys make, he said. But as scientists look for earlier and earlier tools, their findings may begin to resemble the monkey flakes more strongly, said Proffitt, lead author of a study released by the journal Nature. [Source: Associated Press, October 19, 2016 -]
“The work shows that such flakes are not exclusively the calling card of hominins, he said. If somebody finds very old simple flakes, “you can’t assume it is hominin. You have to say it might be produced by an extinct monkey or ape,” Proffitt said. Our African ancestors used sharp-edged stone flakes for butchering and skinning animal carcasses, as well as cutting up tough plant material. To show such flakes were human-made tools, scientists seek evidence like wear marks on the edges or nearby animal bones with marks from butchering. Proffitt and his co-authors studied capuchin monkeys in the Serra da Capivara National Park. They examined the flakes and damaged rocks and compared them to artifacts from human ancestors. It’s not clear why the monkeys smash rocks together, he said. Scientists long thought tool-making was confined to our branch of the evolutionary family tree, the Homo group. But in 2015, scientists reported finding 3.3-millon-year-old tools much older than any known member of Homo. Maybe they were made by some smaller-brained forerunner hominin, like the creature best known for the skeleton nicknamed “Lucy.” *-
“Capuchin monkeys are not hominins, but “the first hominin tools could have looked like the ones produced by capuchins or even great apes,” said Sonia Harmand, an anthropologist at Stony Brook University in New York, one of the scientists who reported the 3.3-million-year-old tools. Harmand, who didn’t participate in the capuchin study, said flakes could have been produced by accident during rock-pounding in ancient times, but that only hominins realized their usefulness and went on to make them deliberately. Alison Brooks, an anthropology professor at George Washington University in St. Louis, said the finding underlines the idea that to identify ancient simple flakes as deliberately made tools, “we need to show that this was more than just a byproduct of pounding.”“ -
Different Kinds of Tool Use by Monkeys
James Gorman wrote in the New York Times: Scientists from the University of Georgia analyzed the motion of capuchin monkeys in Brazil to learn more about what kind of dexterity with tools other primates have. They tracked how high the monkeys lifted stones and how fast they brought them down. The capuchins didn’t just bang away, they adjusted the force of their blows depending on how far they’d gotten with each strike. A world away, in Thailand, another group of scientists studied Burmese macaques cracking shellfish open. They found 17 different patterns of hammering — different strokes for different stones and foods. These monkeys aren’t human ancestors, but these activities may well hint at how the ability to make stone tools evolved. [Source: James Gorman, New York Times, May 18, 2015]
“Monkeys do not exhibit human dexterity with tools, according to Madhur Mangalam of the University of Georgia, one of the authors of a recent study of how capuchin monkeys in Brazil crack open palm nuts. “Monkeys are working as blacksmiths,” he said, “They’re not working as goldsmiths.”But they are not just banging away haphazardly, either. Mr. Mangalam, a graduate student who is interested in “the evolution of precise movement,” reported in a recent issue of Current Biology on how capuchins handle stones. His adviser and co-author was Dorothy M. Fragaszy, the director of the Primate Behavior Laboratory at the university.
“Using video of the capuchins’ lifting rocks with both hands to slam them down on the hard palm nuts, he analyzed how high a monkey lifted a stone and how fast it brought it down. He found that the capuchins adjusted the force of a strike according to the condition of the nut after the previous strike. They bang the nut, check on it and bang it again. How hard depends on whether the nut needs to be cracked a little more, or a lot more. That is not creating fine jewelry but, he and Dr. Fragaszy concluded, it is a kind of dexterity.
“Another study of tool use that came out almost at the same time categorized a variety of movements used by Burmese macaques, a world away, on two islands in Thailand. Amanda Tan, a graduate student at Nanyang Technological University in Singapore, working with her adviser, Michael D. Gumert, used videotapes of the macaques to identify 17 patterns of motion they used with different stones and different foods. The researchers, who published their paper in PLOS One did not do the kind of force analysis conducted for the capuchin motion. But their findings present an intriguingly different example of the evolution of tool use.
“The capuchins were cracking nuts. And although palm nuts are not their only food, they do not have a diet like that of the macaques, who used rocks to crack open 43 species of shellfish, as well as some seeds and plants. They may have developed so many striking patterns involving different kinds of stones because of the variety of food, Ms. Tan said. One of the ways they use stones is called ax-hammering. “They use the sharp points of stones to chip open oysters that grow on rocks,” Ms. Tan said in an email. Only macaques do this, she wrote, and it requires precision, “because they are using a small surface area of the tool to accurately chip open a small target.”That kind of precision was presumably important to our ancestors making flaked stone tools, and the macaques may offer an example of how that kind of motion evolved.
Image Sources: Wikimedia Commons
Text Sources: National Geographic, New York Times, Washington Post, Los Angeles Times, Smithsonian magazine, Nature, Scientific American. Live Science, Discover magazine, Discovery News, Ancient Foods ancientfoods.wordpress.com ; Times of London, Natural History magazine, Archaeology magazine, The New Yorker, Time, Newsweek, BBC, The Guardian, Reuters, AP, AFP and various books and other publications.
Last updated April 2024