Medary.com

Dr Sanz told the BBC: "We found that in the Goualougo Triangle in the Republic of Congo, the chimpanzees were modifying their termite-fishing tools with a special brush tip."

To make their rods, the chimps first picked some stems from the Marantaceae plant and plucked off the leaves.

"They then pulled the herb stems through their teeth, which were partially closed, to make the brush and they also attended to the brush by sometimes pulling apart the fibres to make them better at gathering the termites," Dr Sanz added.