Researchers from Johns Hopkins University said chimps know when humans are struggling with puzzles and tell them the answers.

The team from the university's Social and Cognitive Origins Group claimed to discover that bonobos have social awareness, which was previously thought to be unique to humans.

They worked with bonobos Nyota, 25, Kanzi, 43, and Teco, 13, at the Ape Initiative.

In an experiment, researchers hid treats under cups and when their human partner did not see where the treat was placed, the bonobos quickly and insistently pointed to the right cup. The bonobos also sometimes tapped repeatedly to get their attention.

The results were published in a study in the Proceedings of the National Academy of Sciences on February 2.

Co-author and assistant professor of psychological and brain sciences Chris Krupenye said: 'The ability to sense gaps in one another's knowledge is central to how we cooperate and communicate.

'This work demonstrates the rich mental foundations that humans and other apes share and suggests these abilities evolved millions of years ago in our common ancestors.'

The professor added one of the bonobos was mostly motivated by food.

He said: 'They'd point right through the mesh. Kanzi, especially motivated by food, was quite insistent, tapping several times to guide us.'

Bonobos are a species of great ape closely related to chimpanzees, known for their intelligence and matriarchal social structure. They are native to the dense forests of the Democratic Republic of the Congo and are endangered due to habitat loss and poaching.