Adolescent chimpanzees engage in a charming form of flirting by ripping or plucking leaves near potential mates, according to primate expert Professor Cat Hobaiter from the University of St Andrews.
With over 20 years studying ape communication, Professor Hobaiter identifies leaf clipping as a key gesture. ‘This is basically chimp flirting. It’s like a chimp pick-up line – you tear a little leaf at someone to show you like them,’ she explains.
The Flirting Ritual
Primarily performed by young males to attract females in estrus, the behavior occasionally occurs both ways. Females also use it, akin to teenagers testing social cues. ‘It’s almost like when teenage girls are trying to work out how to get attention,’ Professor Hobaiter notes. ‘You get lots of lovely examples of it as everyone’s trying to work out the rules for this new phase of life.’
The act produces a distinct ripping sound audible from afar, drawing attention. Alternatively, some chimps silently pluck leaves, resembling ‘She loves me, she loves me not.’ This discreet method avoids rivals. ‘Maybe you don’t want to give the game away to the big guy around the corner that might out-compete you,’ she adds.
Study Uncovers Cultural Variations
Researchers analyzed leaf-modifying gestures in two neighboring East African chimpanzee communities in Uganda. Both groups use the behavior mainly for sexual solicitation, especially by young males.
One community favors the ‘leaf-clip’ technique—ripping leaves with the mouth—while the other prefers ‘leaf tear-pull,’ stripping leaves from twigs one by one. These differences suggest socially learned cultural traditions.
The study in Scientific Reports states: ‘Across communities, this behaviour primarily occurs in sexual contexts and is argued to function as a courtship behaviour to solicit copulations… The observed variation in form preference between these neighbouring communities within the same context suggests that these differences are, at least in part, socially derived.’
Ape Gestures Mirror Human Signals
Professor Hobaiter has cataloged 150 ape gestures, many resembling human actions. Chimps extend palms to request items, shoo others away, nudge for space, or scratch loudly to start grooming.
Less intuitive signals include spinning to mean ‘stop that’ or raising an arm for ‘let’s travel.’ She shared these insights at the American Association for the Advancement of Science conference in Phoenix, Arizona.
