Co-author Josep Call told Discovery News that chimps first uproot the stem of a plant "or use their teeth to clip the stem at the base and then remove the large leaf from the distal end by clipping it with their teeth before transporting the stem to the termite nest."
"they complete tool manufacture by modifying the end into a 'paint brush' tip by pullingthe stem through their teeth, splitting the probe lengthwise by pulling off strands of fiber, or separating the fibers by biting them," added Call, a researcher at the Max Planck Institute for Evolutionary Biology.
Call and colleagues observed this process while conducting surveillance at termite nests located at Goualougo Triangle, Republic of Congo. Chimpanzee populations elsewhere are known to do something similar, only with plain-tipped sticks. The scientists determined the brush-tipped tool does a better job, however, since it retrieves more termites.
Call explained that, "termites can bite better the frayed ends since their mandibles get a better grip." Like pulling forks out of a fondue pot, the chimpanzees can then extract the brush tools and gulp down the attached insects. Read the full story by Jennifer Viegas, Discovery News. Watch the video.