Chimpanzees Make Play with Dolls

It's not just tools that other primates create, it's also dolls. Most people probably think of dolls and toys as something that's fairly unique to humans and it turns out that that's not true. The presence of dolls with other primates isn't just interesting because of how it connects them and us; it also helps point out the extent to which young primates need to learn specific social behaviors and have those behaviors transmitted to them from parents... and that's culture.

Sonya Kahlenberg of Bates College in Lewiston, Maine, and Richard Wrangham of Harvard University, found that juvenile chimps in this population play with sticks like children play with dolls, cradling them and even making nests for them to sleep in at night - and they found that the behaviour is more common in females.

Kahlenberg and Wrangham analysed data from 14 years of observation of wild chimps and categorised stick-use into four classes: as probes to investigate holes; as weapons during aggressive displays or attacks; as a prop during solitary play, and, in essence, as dolls. This last class they call "stick carrying", and in 301 observations it turned out to be more common in juvenile chimps, more frequent in females than males, and only occurred in females before their first birth.

On at least 25 occasions the stick-dolls were carried by the young chimps into day nests - a behaviour not observed when sticks were used for other purposes. One young male made a separate nest for his doll, and a female was seen patting a log like she was "slapping the back of an infant", which occurred while her mother was caring for a sick sibling.

Source: New Scientist, December 25, 2010

Play is not something that children do in order to keep from being bored. Play is how children prepare for adult life -- mentally, socially, and culturally. Human children playing with dolls are learning how they will later fill social roles as parents (which is why the way they play and what sorts of dolls they are given carry significant political implications). Chimps playing with "dolls" are also learning how to be parents later on.

But they aren't learning in isolation. They aren't just flailing about randomly, discovering how to "parent" via trial and error. They are learning by watching parents around them and then imitating them. Behaviors are being transmitted from one generation to the next in a manner that is much like how we transmit culture.