Chimps in in Bossou, Guinea have learned to disarm the snares set by local hunters to catch them as bush meat:
“They seemed to know which parts of the snares are dangerous and which are not,” Mr Ohashi told the BBC.
In the journal Primates, the researchers describe six separate cases where chimps were observed trying to deactivate snares.
Mostly, the chimps grasped the snare stick with their hands, shaking it violently until the trap broke.
Sometimes a chimp lightly knocked the sapling that holds the snare, before grasping it to break the trap.
But in all cases, they avoided touching the dangerous part, the wire loop.
This is not the kind of thing a chimp could learn by trial and error.