Why do common chimpanzees use stone?

Common chimpanzees use stones primarily as tools for cracking open hard-shelled nuts, which provides them access to nutritious food. This behavior demonstrates their cognitive abilities, as they select appropriate stones based on weight and shape, showcasing problem-solving skills. Additionally, using stones as tools reflects their capacity for cultural transmission, as specific techniques can be learned and passed down within groups. This tool use is a significant aspect of their foraging strategy, highlighting their adaptability in diverse environments.