A clever monkey has been recorded using self-made tools to give itself a pedicure by removing dirt from under its toenails.
The Mandrill at Chester Zoo was filmed by scientists from Durham University as part of research into the behaviour of the primates, the BBC reports.
In the video, the animal is seen stripping bark off a twig, apparently to make it narrower, before using it to scrape dirt from beneath its nails.
Dr Riccardo Pansini, who led the study, told the news provider the findings suggest the intelligence of the creatures may have been greatly underestimated.
"The gap between monkeys and great apes is not as large as we thought it was in terms of tool use and modification," he said.
While animals such as orangutans and chimpanzees have been seen using crude tools before, until recently it was thought their smaller relatives did not possess these abilities.