Paper short abstract:

Chimpanzee hunting behavior has been observed through their ranges. Meanwhile, local differences have been found in this behavior. For example, blue duikers were hunted by chimpanzees in Tanzania, whereas chimpanzees in Ivory Coast did not hunt them. These common features and local differences of this behavior will be discussed.

Paper long abstract:

Chimpanzee (Pan troglodytes) hunting behavior has been observed through their inhabited ranges irrespective of the vegetation types. The main targets of chimpanzee hunting were sympatric primates and red colobus monkeys (Procolobus badius) were most frequently hunted where chimpanzees and this species occurred sympatrically. Meanwhile, local differences have been found on this behavior. For example, blue duikers (Cephalophus monticla) were hunted by chimpanzees at the Gombe National Park and the Mahale Mountains National Park in Tanzania, whereas chimpanzees at the Tai forest in Ivory Coast did not hunt them in spite of blue duikers inhabiting there. Although population densities of red-tailed monkeys (Cercopithecus ascanius) were the almost same as these of red colobus monkeys at Mahale, frequencies of chimpanzee hunting were different: red colobus monkeys were frequently or regularly hunted by chimpanzees but red-tailed monkeys were not. Also, local differences of interspecific relationships between chimpanzees and red colobus monkeys and the technic of chimpanzee hunting on red colobus monkeys have been found. These common features across their inhabited ranges and local differences of chimpanzee hunting will be discussed.

Paper short abstract:

Taste allows mammals to evaluate their foods and determine which foods they can ingest. There are some reports on the individual and regional differences in the food items of non-human primates. We found the genetic differences in the taste receptors of primates, which are specific for local area and might affect the feeding behaviors of primates.

Paper long abstract:

Taste allows mammals to evaluate their foods and determine which foods they can ingest. There are some reports on the individual and regional differences in the food items of non-human primates as well as human. We hypothesized that the genetic difference in the taste receptor is one of the determinants of the local differences in behavior and feeding ecology. In case of human, genetic differences were reported for some of bitter taste receptors, TAS2R. For example, mutation of TAS2R38 is responsible for the individual difference in the bitter taste sensitivity of phenylthiocarbamide (PTC).

We found the intra-and inter-species genetic differences in the taste receptors of non-human primates. In case of macaques, mutation of TAS2R38 was found to be limited to the specific region in Japan (1). In case of chimpanzees, mutation of TAS2R38 was found to be limited to the western chimpanzees (2, 3). These mutations occurred independently and might affect the feeding behaviors of primates.

1. N. Suzuki, T. Sugawara, A. Matsui, Y. Go, H. Hirai, and H. Imai Identification of non-taster Japanese macaques for a specific bitter taste. Primates 51, 285-289 (2010).

2. T. Sugawara, Y. Go, T. Udono, N. Morimura, M. Tomonaga, H. Hirai, and H. Imai. Diversification of bitter taste receptor gene family in western chimpanzees. Mol. Biol. Evol. 28, 921-931 (2011).

3. T. Hayakawa, T. Sugawara, Y. Go, T. Udono, H. Hirai, H. Imai. Eco-geographical diversification of bitter taste receptor genes (TAS2Rs) among subspecies of chimpanzees (Pan troglodytes). PLOS ONE 7, e43277 (2012).

Paper short abstract:

Behaviors of wild chimpanzees differ significantly among different study populations. Some of such differences cannot simply be explained in terms of ecological or genetic differences. I will summarize recent findings of such behavioral diversity, or culture, among chimpanzees.

Paper long abstract:

Long-term studies of wild chimpanzees (Pan troglodytes), phylogenetically closest living species to us humans, have been conducted over decades. Accumulation of knowledge about their behaviors from different study sites across Africa has revealed that their behaviors differ significantly among different populations. On the other hand, many behavioral patterns are shared by most of the members within a social group and are consistent over decades. Because some of such behavioral variation among groups cannot simply be explained in terms of ecological or genetic differences, such behaviors are thought to be socially acquired and inherited within a group. Such behavioral diversity of chimpanzees is often called ﾓcultureﾔ by some primatologists, although there are hot debates over whether or not we should call it so. In this presentation, I will summarize recent findings of such behavioral diversity, or culture, among chimpanzees by introducing some examples of behaviors. Although many studies of chimpanzee culture focus on its material and technological aspects, i.e. various types of tool-use and object-use, I would like to emphasize that behavioral diversity in chimpanzees is not restricted to such a domain. Even a very subtle and simple behavioral patterns, such as how to scratch others, how to get an attention of the prospective mate, or how to squash a parasite, are somehow shared within a group but differ between groups.

Paper short abstract:

Commenting cultural anthropologically on each paper from 3 points: 1. theoretical concept of culture in non-human primates; 2. are local differences for non-human primates limiting condition or driving force for creating culture?; 3. any identity or “ethnicity” among non-human primates?

Paper long abstract:

When we examine a certain human phenomenon, a cultural anthropologist has little or no hesitation to assume that it is culture. Conversely, a primatologist is more careful to regard a certain behavior as "culture". It is partly derived from each academic history, but even more so from general discourse of modern era. Modern age has, rather, considered everything as human creation, culture, while stressing, not found in animals. We should pay more attention to non-human primates’ transmitted collective behavior as culture.

I would examine the papers from three points. First, I am interested in the initial presumption of the panelists that they can discover the collective behavior among the non-human primates under observation. What they found might have been what they wished to find. I am skeptical.

Secondly, if the process of cultural evolution of non-human primates is that environmental difference makes a certain characteristic more adaptive to the natural circumstances, and then consequentially forces its features’ expansion, it would seem contrary to how human culture is created. Human culture has been developed in a way where it tends to get over the natural environment of humans, which is seen as a limiting condition, but it seems precisely this environment that serves as a driving force for non-human primates’ evolution.

Lastly, I would like to know if we could go on and find further cultural identity or “ethnicity” among non-human primates. Do non-human primates use certain cultural traits to exclude, or include, other mates from and into their group?