Scientists have described a tradition of putting a piece of grass in the ear and anus of a group of chimpanzees in the Chimfunshi Nature Reserve (Zambia). Copying each other’s actions can strengthen the primates’ social bonds, a scientific news portal reported N+1.
In 2010, in the Chimfunshi Nature Reserve, a female chimpanzee, Julie, began walking around with a piece of grass in her ear. Within three years, this trend had spread to 8 of the 12 chimpanzees in the group. This behavior was not observed in individuals from other groups. Two chimpanzees from this group still have a piece of grass in their ears.
In early August 2023, male Juma became the first of his group to insert a blade of grass into his ear. Gradually, five other chimpanzees in the group, as well as one of the migrant individuals, joined the group. Also at the end of August 2023, Juma began inserting a piece of grass into his anus. The same day, another chimpanzee did the same, and three days later, five monkeys did the same.
In both cases, scientists noted that the chimpanzees’ behavior was a cultural tradition: some individuals in the group learned from others. Copying behavior may be associated with the chimpanzees’ desire to “fit in” with their relatives and serve to strengthen social bonds.
Formerly a chimpanzee learned Pronounce individual words of human speech.