Thank you for visiting nature. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser or turn off compatibility mode in Internet Explorer.
In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript. Long-term social recognition is vital for species with complex social networks, where familiar individuals can encounter one another after long periods of separation.
For non-human primates who live in dense forest environments, visual access to one another is often limited and recognition of social partners over distances largely depends on vocal communication. Vocal recognition after years of separation has never been reported in any great ape species, despite their complex societies and advanced social intelligence.
Here we show that bonobos, Pan paniscus, demonstrate reliable vocal recognition of social partners, even if they have been separated for five years. Despite long separations, subjects responded more intensely to familiar voices than to calls from unknown individuals - the first experimental evidence that bonobos can identify individuals utilising vocalisations even years after their last encounter.
Our study also suggests that bonobos may cease to discriminate between familiar and unfamiliar individuals after a period of eight years, indicating that voice representations or interest could be limited in time in this species. The social life of many primate species is characterised by lasting associations between individuals, making individualised social knowledge of primary importance. Individual vocal recognition has been found in many primate species 1 , 2 , 3 , 4 , 5 , 6 and is particularly important for those living in dense forest habitats where vocalisations are often the most efficient communication channel 7.
