Chimpanzees commonly use a twig to extract termites from termite mounds.
A chimpanzee typically selects a flexible plant stem, strips away leaves, and inserts the resulting probe into tunnels in a mound. Termites seize or climb onto the twig, allowing the chimpanzee to withdraw it and sweep the insects into its mouth. Some communities use additional sticks to open the mound or enlarge its holes.
This behavior became famous through Jane Goodall’s observations at Gombe Stream National Park in Tanzania. In 1960, her reports that chimpanzees modified and used leafy twigs challenged the idea that tool-making sharply separated humans from other animals.
The exact technique varies between communities, and termite fishing is partly learned socially. Chimpanzees also use stones to crack nuts and leaves as absorbent tools, so the alternatives are genuine chimpanzee tools—but a twig is the characteristic probe for termite fishing. “Stick” is also broadly correct, but “twig” is the standard answer for this question.