Unlike chimpanzees, which famously tinker with sticks and stones, wild gorillas are notoriously rare tool users. Captive gorillas regularly manipulate branches and twigs, but researchers have documented only two instances of the great ape using tools in the wild; one used a stick to explore the depth of a muddy river and another turned a tree trunk into a makeshift bridge. Now, scientists may be adding new instruments to the wild gorilla’s tiny toolbox: ladders. Researchers working at the Volcanoes National Park in Rwanda spotted an adult female mountain gorilla (Gorilla beringei beringei) using a thick bamboo shoot to help her distressed infant climb from a thicket on the jungle floor to her higher perch (shown above), the team reports this month in Behavioural Processes. The team says the novel behavior was more than mere coincidence because the mother lowered the bamboo shoot only after she heard her infant cry out for help and watched him fail to climb up the thicket by himself. When the infant gorilla grabbed the lowered pole, the mother then grasped it more firmly, which allowed the infant to scurry up to join her. Scientists suggest that wild gorillas use tools to overcome physical obstacles in their rugged habitat, rather than to forage for food, like chimpanzees and orangutans.

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