Creatures of Culture? Making the Case for Cultural Systems in Whales and Dolphins

Features SCOTT NORRIS O n a typical summer day, the waters of Johnstone Strait, in British Columbia, are abuzz with the clicks, whistles, and pulsed calls of killer whales. These animals—the summer residents of the inland waterways off northern Vancouver Island—are perhaps the most intensively studied whale population in the world. Through research based on the ability of observers to visually identify every individual in the population, scientists have put together an extensive and detailed outline of the whales’ social relationships over the last three decades. And since the early 1980s, researchers have had hydrophones in the water, recording myriad hours of whale conversation. A killer whale surfaces in Johnstone Strait, British Columbia. Differences in dorsal fin shape and markings allow researchers to identify roughly 300 individuals in the summer resident population. Photograph: Volker Deecke. The glimpse these studies provide into the life of a creature as far removed from ourselves as the killer whale represents a triumph of field biology. Among the tight associations of family groups known as pods, researchers have found stable and distinct vocal patterns, or dialects, that appear to be maintained and transmitted by social learning. For a growing number of scientists, the implications of such patterns are clear: Killer whales are highly cultural creatures and may stand alongside—and perhaps in some ways ahead of—chimpanzees as the exemplar of a nonhuman animal whose life and evolution is shaped by cultural processes. And killer whales may not be unique: In recent years, intriguing evidence of cultural processes has surfaced in other whale species as well. But as one might expect, claims of culture in cetaceans (whales and dolphins) have sparked controversy. The idea that nonhuman animals can possess culture has long been a contentious issue among behavioral scientists. Recently, biologists, psychologists, social scientists, and philosophers squared off in a lengthy printed debate over the existence of culture in whales and dolphins. The occasion of this remarkable discussion was the publication, in the journal Behavioral and Brain Sciences (volume 24, April 2001), of a paper by two whale reJanuary 2002 / Vol. 52 No. 1 • BioScience 9 Creatures of Culture? Making the Case for Cultural Systems in Whales and Dolphins Features The interpretation of culture Culture may be broadly defined as shared variation in behavior that is generated and maintained by social learning, for example, through imitation or teaching. Although many researchers generally agree with this definition, sharp differences exist over its interpretation and application. For Rendell and Whitehead, as for many field biologists, the specific mechanism of information transfer is of less importance than the patterns it generates. Social learning is often very difficult to demonstrate directly. But the presence of culture can be established by observation and deduction: When behavioral differences exist that cannot be accounted for by genetic or environmental factors, cultural transmission must be occurring. The strength of this approach, Whitehead notes, “is that it is firmly rooted in what the animals actually do in the wild.” Critics have several responses. First, it may often be quite difficult to rule out alternative hypotheses suggesting that either genes or learned individual responses to differing environments are responsible for behavioral patterns. Often implicit in this argument is the notion that social learning, thought to be a more complex and cognitively demanding phenomenon than individual learning, should be invoked only as an explanation of last resort. In effect, when it comes to animals, it may be safer to assume that individuals repeatedly reinvent the wheel than to suppose they learn from or imitate the behavior of others, at least until proven otherwise. A second approach to animal culture is one generally favored by psychologists and behavioral researchers working in experimental settings. According to this view, culture should not be attributed to a species until controlled experimental studies have established a cognitive capacity for social learning—imitation and teaching in particular. “In order to understand cultural phenomena you have to understand the underlying processes, and not focus solely on the results of those,” says Stan Kuczaj, a behavioral psychologist at the University of Southern Mississippi, in Hattiesburg. Although the debate over definitions and evidence remains polarized to some extent, many researchers agree that multiple approaches are needed to understand the behavior of advanced and highly social animals like chimpanzees and whales. And although some scientists still deny culture even to chimps, strict behaviorist approaches may be on the wane. At the same time, observational studies are now gaining some of the scientific rigor they have lacked in the past. For Rendell and Whitehead, the important thing is to approach culture in such a way that all of the evidence may be considered. Given all that has been learned from field studies, they argue, culture should not be denied pending experimental data that may be impossible to collect for many cetacean species. Matrilineal whales— structure and tradition Killer whale nuclear family—a mother and her two calves. Males remain in close association with their mothers throughout life, whereas females eventually form their own matrilineal group. Pods consist of one to nine of these groups. Photograph: Scott Norris. 10 BioScience • January 2002 / Vol. 52 No. 1 The strongest case for cetacean culture may come from killer whales. The social universe of these animals consists of a highly stable, hierarchical set of relationships based on the matriline, that is, the family group consisting of a mother and her offspring. In British Columbia, male whales remain with their mothers until the mothers die. Females eventually mate and form their own matriline. Small numbers of related matrilineal groups band together in highly cohesive units known as pods. Pod members travel and forage together; in over 20 years of study, no individual has switched from one pod to another. At an even higher level, different pods preferentially associate and share vocal elements with one another. searchers who attempted the first general review of the evidence for culture in cetaceans. Hal Whitehead and Luke Rendell, both of Dalhousie University, argued that cetaceans possess cultural faculties unique in the animal kingdom— except for humans. The paper appeared together with 39 written commentaries, some supportive and some strongly critical, and an authors’ response. If nothing else, Rendell and Whitehead’s paper and the subsequent debate signify a coming of age in cetacean field studies. The discussion is important not just for the light it sheds on one particular group of organisms but also because it points to lar (...truncated)