Animal Culture - Primate Culture

Primate Culture

The beginning of the modern era of animal culture research in the middle of the 20th century came with the gradual acceptance of the term "culture" in referring to animals. Japan's leading primatologist of the time, Kinji Imanishi, first used the word with a prefix as the term "pre-culture" in referring to the now infamous potato-washing behavior of Japanese macaques. In 1948, Imanishi and his colleagues began studying macaques across Japan, and began to notice differences among the different groups of primates, both in social patterns and feeding behavior. In one area, paternal care was the social norm, while this behavior was absent elsewhere. One of the groups commonly dug up and ate the tubers and bulbs of several plants, while monkeys from other groups would not even put these in their mouths. Imanishi had reasoned that, "if one defines culture as learned by offspring from parents, then differences in the way of life of members of the same species belonging to different social groups could be attributed to culture." Following this logic, the differences Imanishi and his colleagues observed among the different groups of macaques may suggest that they had arisen as a part of the groups' unique cultures. The most famous of these eating behaviors was observed on the island of Koshima, where one young female was observed carrying soiled sweet potatoes to a small stream, where she proceeded to wash off all of the sand and dirt before eating. This behavior was then observed in one of the monkey's playmates, then her mother and a few other playmates. The potato-washing eventually spread throughout the whole macaque colony, encouraging Imanishi to refer to the behavior as "pre-culture," explaining that, "we must not overestimate the situation and say that 'monkeys have culture' and then confuse it with human culture." At this point, most of the observed behaviors in animals, like those observed by Imanishi, were related to survival in some way.

The first evidence of apparently arbitrary traditions came in the late-1970s, also in the behavior of primates. At this time, researchers McGrew and Tutin found a social grooming handclasp behavior to be prevalent in a certain troop of chimpanzees in Tanzania, but not found in other groups nearby. This grooming behavior involved one chimpanzee taking hold of the hand of another and lifting it into the air, allowing the two to groom each other's armpits. Though this would seem to make grooming of the armpits easier, the behavior actually has no apparent advantage. As Frans de Waal explains from his later observations of the hand-clasp grooming behavior in a different group of chimpanzees, "A unique property of the handclasp grooming posture is that it is not required for grooming the armpit of another individual... Thus it appears to yield no obvious benefits or rewards to the groomers."

Prior to these findings, opponents to the idea of animal culture had argued that the behaviors being called cultural were simply behaviors that had evolutionarily evolved due to their importance to survival. After the identification of this initial non-evolutionarily advantageous evidence of culture, scientists began to find differences in group behaviors or traditions in various groups of primates, specifically in Africa. More than 40 different populations of wild chimpanzees have been studied across Africa, between which many species-specific, as well as population-specific, behaviors have been observed. The researching scientists found 65 different categories of behaviors among these various groups of chimpanzees, including the use of leaves, sticks, branches, and stones for communication, play, food gathering or eating, and comfort. Each of the groups used the tools slightly differently, and this usage was passed from chimpanzee to chimpanzee within the group through a complex mix of imitation and social learning.