INTRODUCTION Culture in social behaviours Humans (Homo sapiens) have various types of behaviours that vary across populations, generations or ethnic groups, and which we label ‘culture’. Among these behaviours, those used in social interactions are quite familiar to us. For example, even the inter-individual distances in particular social situations differ between different ethnic groups (Hall 1966), and the ways of greeting often vary between different countries (e.g. Collet 1993). Handshaking is common among westerners (Kendon & Ferber 1973), whereas Japanese usually do not shake hands but bow to each other (Nomura 1994), and Tongwe people in Tanzania traditionally clap their hands to each other (Itani et al. 1973). Such behaviours are often so deeply embedded in our everyday lives that we are not aware that they are culturally rooted. The most interesting characteristic of such behavioural diversity in the social domain may be that some of the differences seem almost irrelevant to the functions of these behaviours. Also, the rationale for a particular variation in a behaviour versus another variation in that behaviour does not significantly help us to understand the differences. Rather, we perform these behaviours in the ways we do ‘because the person in the front performs like this’, or ‘because people say it is the proper etiquette to follow’. In other words, these cultural behaviours often only have significance in interactions among individuals. Many of us are ready to admit that our human cultures have such a characteristic. However, is this characteristic unique to humans? What about our closest relative species, the chimpanzees (Pan troglodytes)? In this chapter, I focus on those aspects of chimpanzee cultures that are possibly shaped in and/or by their everyday interactions.