Orangutans at a zoo in Germany were set a task by zookeepers to get their dinner out of a locked box.
The animals at Hagenbeck Zoo in Hamburg were pictured attempting to manoeuvre food from out of the box using sticks as part of an enrichment exercise.
The apes soon had something of an audience as they attempted to tease the treats out of holes in the box's side.
They were watched by several curious otters before they got in on the action too and tried to open the box from the other side.
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