大象传媒

Brown-tufted capuchins are highly intelligent creatures. They spend their nights in the safety of caves, emerging each morning to find food. Down in the valley is a particular favourite, a nut palm. The palms produce huge seeds, but have very stong shells that protect them against attack. For the capuchins, this is a war of attrition. They check which nut is ripest and tear the husk off. Then, rather than trying to crack the nut straight away, they drop it on the ground, because these Brazilian monkeys have learned that the nuts can be cracked only if they're left to dry out in the sun. After a week or so, the capuchins return to their stash and tap the nuts to see if they're ready. Then, using a flat rock as an anvil, they bash the nut with a harder variety of rock, or hammer, and crack open the tough nuts. Using separate tools in this way requires an exceptional level of intelligence and dexterity. Youngsters copy the behaviour from their parents, just like human toddlers, but it can take up to 8 years for them to learn the intricacies and source the right tools.