Animal cultures

For most biologists, 'culture' is either some agar-bound growth in a Petri dish or the nebulous domain of fashion, art and theatre that lies at the edge of scientific understanding. For an increasing number of animal behaviourists, however, 'culture' has a quite different meaning: the learning and social transmission of knowledge and skills among animals. The best-known examples include the opening of milk bottles to drink cream by European birds, the washing of food by Japanese macaques, and the habit, of some East African chimpanzees, of fishing for termites with stalks. Animals as diverse as ants, sticklebacks and killer whales are now known to pick up foraging skills, dietary preferences, mating preferences and predator evasion tactics, and to learn calls, songs, and migratory routes, by observing more experienced others. But the claim that humans are not the only species immersed in a cultural realm is shrouded in controversy. Why study animal culture? Why is culture of interest? Many people who study animal cultures, particularly primatologists, do so because they believe their research will shed light on the evolution of human cognition. Animal social learning, it is argued, lies at the roots of human culture. If we can get to grips with termite fishing in chimpanzees or macaque food washing, they surmise, we can gain insights into homologous processes that led to the emergence of 'full-blown' culture in humans, the conditions that favored the cognitive underpinnings of our own cultural capability, or the evolutionary trajectory of our cultural ancestors. Whatever the merits of that argument, from the evolutionary biologist's perspective, animal culture is inherently interesting. That is, there are broader issues that validate investigating animal cultural processes over and above the light such study sheds on our own species. Primer effects of these phase change genes and elucidate the regulatory networks involved. How and why do swarms form? Weather plays a critical role in locust population growth and swarm formation, because it promotes growth of host plants and provides soil moisture for egg development. Individual-based computer simulations, laboratory and field experiments have shown that the fine-scale spatial distribution and quality of resources in the habitat can either promote or deter contact among individuals, and hence influence the probability of locusts entering the gregarious phase. Clumping of food plants or areas of favourable microclimate encourages solitarious locusts to come into contact and gregarise, despite their initial tendency to be repelled by one …