Marmosets, small monkeys living in family groups, use special whistles called 'phee calls' to communicate with each other.
A new study has found that these monkeys use different 'phee calls' for each individual marmoset, similar to how humans use names.
This is the first time this behavior has been seen in non-human primates, and researchers believe it helps maintain social harmony within the group.
The study suggests that vocal learning might be more common in primates than previously thought, offering insights into the evolution of human language.