By primatologist José María Bermúdez de Castro – Scientific Advisor to the Gran Simio Project (GAP/PGS Spain)

If we ask what culture is, everyone will have difficulties to give a precise definition. Human culture includes various aspects, and it is very difficult to summarize and synthesize their meaning in a nutshell. Among these aspects, we have the form of conduct of certain social groups and their, more or less complex, traditions passed on from generation to generation.

In all animal species it is observed specific and repetitive behavior forms that take place naturally. However, various “experts” have demonstrated unique and reflective behaviors in chimpanzees, orangutans, dolphins and whales. In particular, ethologists have observed a number of very specific behaviors in groups of chimpanzees. They have described this conduct as a true culture of our closest relatives. Social learning is a kind of secondary hereditary system, which interacts with genetic inheritance and enriches the evolution of behavior. Humans have developed tremendously this aspect, but they are not the only ones.

Chimpanzees seem to be the mammals with greater capacity for social learning, which comprises close to 40 different forms of social learning that distinguish one clan from others. Scientists have observed traditions, which include the use of stone tools for certain functions related to food. Definitely, these cultural forms always imply a particular innovation in each group. If this innovation results useful, it ends up being the common behavior of all group members. If its members do not communicate with other nearby groups, innovation is not transmited to chimpanzees in a given region. However, this is not usual, due to the interaction between groups of female chimpanzees to avoid inbreeding. This is a very effective method to enhance social learning and its transmission to other clans.

In a paper published this past September by Catherine Hobaiter and other colleagues in the journal PLoS Biology, it was given a further step in the characterization of social learning through a mathematical algorithm, which has been praised by Andrew Witen in the journal Nature. Catherine Hobaiter and her group observed the Sonso community of chimpanzees in the Budongo Forest, Uganda. This community is being studied for 20 years.

Like most chimpanzees, Sonso members have used a kind of container formed by leaves to extract water from tree trunks. On November 14, 2011, it was noted that the alpha male wore a sponge formed by mosses to extract a certain local water, as he was being observed by the dominant female. The water seemed to be rich in certain minerals and appreciated by the members of the clan. Shortly this innovation launched by the alpha male to extract water was adopted by other members of the community, but not all. Hobaiter and her colleagues took note of the whole process and applied a new statistical method, which improved the observations, taken from a previous work on whales that numerically shows the process of cultural transmission in chimpanzees community.

The method is very complex from the mathematical point of view, but it can be understood by those who have interests to know it (the magazine is online, open to all). The most interesting is to reflect how our ancestors were able to use social learning to create the cultural complexity that we now have. The model of exchanging females in groups of chimpanzees was also used by our ancestors, contributing to a very slow diffusion of innovations. Moreover, it is worth remembering that chimpanzees, animals that we have been using for our own amusement and exhibition in zoos, represent a unique source of information to know the origins of our culture. This is their legacy and we must take seriously the respect we owe to them, considering we still have much to learn from these animals.