It's now well-established that humans and Neanderthals lived alongside each other and interbred for thousands of years, and genetic researchers have found that up to around 4 per cent of our modern human genome came from our Neanderthal cousins.
Now scientists from the Wellcome Trust Sanger Institute in Cambridge have found that the ancestors of chimps and bonobos also got up to the same monkey business back in their evolutionary history.
Writing in the journal Science, the team analysed DNA from 75 chimps and bonobos in 10 African countries and showed that one percent of chimpanzee genomes are derived from bonobos, even though the two species officially split between 1.5 and 2 million years ago.
There seems to have been at least two periods of subsequent interbreeding, with the last happening as recently as 150,000 years ago. The scientists also discovered a strong link between a chimp's DNA sequence and its country of origin, which could be useful for conservationists trying to work out where chimps are being illegally captured.