Why it's natural for girls to play with dolls and boys to love guns
Girls play with dolls because they’re programmed to, not because of any sexual stereotyping, new research suggests.
Young chimps in the wild play play boy and girl games, much like their human counterparts, scientists found. Although both male and female chimpanzees play with sticks, girl chimps treat sticks like dolls copying their mothers as they care for infants.
The findings suggest girls play more with dolls than boys not because of sex-stereotyped socialization but because of ‘biological predilections.’
Richard Wrangham of Harvard University said: ‘This is the first evidence of an animal species in the wild in which object play differs between males and females.’
Earlier studies of captive monkeys had also suggested a biological influence on toy choice. When juvenile monkeys are offered sex-stereotyped human toys, females gravitate toward dolls, whereas males are more apt to play with ‘boys’ toys’ such as trucks.
The findings were the result of 14 years of observation of the Kanyawara chimpanzee community in Kibale National Park, Uganda. It found that chimpanzees use sticks in four main ways, as probes to investigate holes potentially containing water or honey, as props or weapons in aggressive encounters, during solitary or social play, and in a behaviour the researchers refer to as stick-carrying.
Mr Wrangham said: ‘We thought that if the sticks are being treated like dolls, females would carry sticks more than males do and should stop carrying sticks when they have their own babies. 'We now know that both of these points are correct.’
Young females sometimes took their sticks into day-nests where they rested and sometimes played with them casually in a manner that evoked maternal play. However scientists are unsure if stick-carrying was a form of play for all chimp clans or was just a ‘social tradition that has sprung up’ in the study group.
If it was found to be unique to the Kanyawara chimps ‘it will be the first case of a tradition maintained just among the young, like nursery rhymes and some games in human children. ‘This would suggest that chimpanzee behavioural traditions are even more like those in humans than previously thought.’
The findings were published in the latest issue of Current Biology