A particularly clever band of chimpanzees living in one area of the Congo basin have found a better way to fish for food in termite mounds. Zoologists have long known that chimps eager for a tasty termite snack use a short stick, which is thrust into the termites’ nest. The insects bite on the intruding probe and are then extracted and slurped down [AFP]. But chimps living in an area called the Goualougo Triangle in the Republic of Congo have been observed crafting more complex tools that increase their haul of insect morsels.
Instead of using a simple pointed stick, lead researcher Crickette Sanz says these chimps modify their tools by making a special brush tip. To make their rods, the chimps first picked some stems from the Marantaceae plant and plucked off the leaves. “They then pulled the herb stems through their teeth, which were partially closed, to make the brush and they also attended to the brush by sometimes pulling apart the fibres to make them better at gathering the termites,” Dr Sanz added [BBC News].
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Capuchin monkeys not only have the capacity to use tools, they also know which tool is best for the job at hand, according to a new study. Researchers observed capuchin monkeys in the wild testing out different stones and consistently settling on the heaviest, sturdiest stone to crack open palm nuts. Although anecdotal reports existed before, the new study is the first to systematically document tool use in capuchin monkeys. Because capuchins last shared a common ancestor with humans approximately 35 million years ago, the team writes, the capacity for stone-tool use evolved earlier than thought [New Scientist].
Researchers studied eight wild capuchins living in a forested area of Brazil. In several different trials, researchers planted two or three different rocks, of varying hardness, size, and weight, near where the monkeys were feeding. The choices ranged from crumbly sandstone to tough quartzite, with some artificial stones that the monkeys would not normally encounter also thrown in the mix. Capuchins chose the most effective stone for cracking nuts more than 90 percent of the time in four conditions. That figure fell slightly to 85 percent when the monkeys selected from artificial stones of the same size and different weights [Science News].
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