For decades, we have believed that the spread of culture and ideas was something unique to humans in the animal kingdom. However, scientists have found direct evidence that wild chimpanzees also learn new skills from each other and develop a new culture. For the first time, scientists firsthand witnessed a new behavior being transmitted to one member to another in a group of chimpanzees in real-time.
Scientists monitored Sonso chimpanzees for six days
Researchers led by Dr Catherine Hobaiter of the University of St Andrews conducted a long-term study of chimps living in the Budongo forest of Uganda. They noticed two instances of transmission of new tool-making skills among members of a group of Sonso chimpanzees. Hobaiter explained that these animals use folded up sponges to suck the water from ponds.
Dr Catherine Hobaiter said she and her colleagues were extremely lucky to be in the right place at the right time to document the spread of two novel behaviors. Chimps usually make leaf sponges by folding and chewing the leaves. During their six days of observation, scientists observed that many individuals of the chimp community developed two novel behaviors.
One behavior was that of reusing the leaf-sponge, where a chimpanzee used a sponge left from a previous visit. Second was moss-sponging, in which a chimp makes a sponge from moss or a mixture of moss and leaves. Neither of the two behaviors had previously been observed in the Sonso chimp community. Hobaiter noticed an alpha male chimp making a moss sponge and using it to extract water while an adult female observed it.
Chimpanzee culture changes little by little
Over the next six days, chimpanzees revisited the pond regularly. And scientists noticed that another seven individuals had picked up the skills. They too were making and using moss sponges just like the first chimp. Researchers confirmed that six of these had observed the new skill before adopting it themselves. The seventh was found to re-use a discarded moss sponge, so it could have picked up the skills in this way.
Moving on to the skill of reusing a leaf-sponge, scientists noticed a 12-year old male retrieving and using a discarded leaf-sponge. Soon, another eight individuals adopted this technique. However, only four of those eight had first observed another individual doing it before they started doing it themselves. Dr Thibaud Gruber of the University of Neuchatel said that the new behaviors were variants of well-known, old sponge-making techniques. It suggests that the chimp culture changes “little by little.”
Findings of the study were published in the journal PLOS Biology.