ANIMAL BEHAVIOUR

any observable activity of a whole living animal. The ways in which animals solve their common problemse.g., eating, drinking, protecting themselves from predators, reproducing, and groomingare all the concerns of an ethologist, a scientist who studies animal behaviour. Animal behaviour is largely dictated by innate programming. Depending on external factors such as the season or the cycle of the Moon, an animal's body may secrete hormones that regulate its metabolism or behaviour. Hormones, for example, will decrease a bear's metabolic rate until the animal falls into a torpid state that lasts throughout the winter, and other hormones encourage the bear throughout its active months to consume enough food so that it will survive hibernation. None of this is under the bear's conscious controlno more than a woman can control her menstrual cycle. Animals solve their problems in a variety of ways. In the winter, birds remedy their reduced food supply by migrating toward the Equator or Southern Hemisphere where the seasons are reversed. It is not fully known whether birds navigate over long distances by the stars and Sun or by a compass sense. Nor can the behaviour of salmon, which find their way back to the same freshwater where they were born after years in the ocean, be explained. Some hormones are produced at particular times; e.g., sex hormones, which prepare the body for parenthood. Other hormones may be triggered by a particular occurrence, such as the sight of a predator. Many animals also secrete chemical substances called pheromones, which send messages to other animals. When a female fly is ready to produce eggs, she releases a pheromone into the air. A male that smells this substance will immediately approach and inseminate the female or any object that a scientist may have dabbed with the pheromone. Pheromones can also serve as a message between males, as when a dog marks with urine what it would like to claim as its territory. Still other pheromones transmit information to the entire group, as in an ant trail that leads to a food source. Animals that live in communities demonstrate a variety of social behaviour. Some perform actions that benefit others without receiving any direct benefit themselves. Animal altruism helps to preserve a species, as when parents gather food for their young and protect them against predators. Similarly, rats and monkeys in laboratory experiments will sacrifice food rather than allow others of their species to receive an electrical shock. Complex animal societies tend to build shelters (e.g., an ant hill), while others establish and guard territories. A pattern of leaders and followers within an animal society indicates some social organization, as in herds of sheep or schools of fish, but does not always indicate that the group has a leader. Among many species of birds, for example, different members lead the flock during a single flight. A dominance hierarchy, in which one animal bullies another into submitting to its wishes, is present in almost all animal interactions and does not indicate social organization. Ethologists argue that the more advanced animal societies do not have dominance hierarchies. Other factors of social behaviour in animals include migration patterns and labour division. Social behaviour should not be correlated with intelligence or with evolutionary development. The simplest organisms form colonies, and the most complex colonies are formed by the relatively simple ant and bee. Man, the highest animal on the evolutionary scale, can be relatively solitary. Social behaviour is not a key to evolutionary development but rather is the adaptation of animals to the world around them. any activity of an intact organism. A living animal behaves constantly in order to survive, and all animals must solve the same basic problems. They must, for instance, periodically replace their energy source (consume food), avoid dehydration (drink), avoid becoming another animal's energy source (avoid being eaten), maintain their body surfaces (clean and groom), and reproduce. This article discusses the basic behavioral activities of animals ranging from protozoans to higher vertebrates. Although references are made to human behaviour, the reader should consult human behaviour, for specific information. Likewise treated in passing are certain behavioral tendencies of plants that resemble or parallel simple unlearned behavioral responses and adaptive mechanisms of animals (see also plant development). Additional reading General works Konrad Lorenz, King Solomon's Ring: New Light on Animal Ways (1952, reissued 1991; originally published in German, 1949), is a highly recommended popular treatment. Peter Marler and William J. Hamilton III, Mechanisms of Animal Behavior (1968), is also of interest. Semipopular works include Niko Tinbergen, Curious Naturalists, rev. ed. (1974, reprinted 1984), highly recommended to all interested in behaviour; and Niko Tinbergen et al., Animal Behavior, rev. ed. (1980), an excellent rsum of ethology. Marc Bekoff and Dale Jamieson (eds.), Interpretation and Explanation in the Study of Animal Behavior, 2 vol. (1990), is a collection of interdisciplinary essays covering a wide range of topics. Bonnie V. Beaver, The Veterinarian's Encyclopedia of Animal Behavior (1994), is easy to read and describes normal and abnormal animal behaviours and specific subjects in alphabetical order. Nature and patterns of animal behaviour Studies include Claire H. Schiller (trans. and ed.), Instinctive Behavior (1957); Anne Roe and George Gaylord Simpson (eds.), Behavior and Evolution (1958); Kenneth D. Roeder, Nerve Cells and Insect Behavior, rev. ed. (1967); Irenus Eibl-Eibesfeldt, Ethology: The Biology of Behavior, 2nd ed. (1975; originally published in German, 1966); J.E.R. Staddon, Adaptive Behavior and Learning (1983); Jeffrey M. Camhi, Neuroethology: Nerve Cells and the Natural Behavior of Animals (1984); Matthew H. Nitecki and Jennifer A. Kitchell (eds.), Evolution of Animal Behavior: Paleontological and Field Approaches (1986); and John Alcock, Animal Behavior: An Evolutionary Approach, 5th ed. (1993). More advanced treatments are Eugene L. Bliss (ed.), Roots of Behavior: Genetics, Instinct, and Socialization in Animal Behavior (1962); Konrad Lorenz, Evolution and Modification of Behavior (1965, reprinted 1986); Robert A. Hinde, Animal Behaviour: A Synthesis of Ethology and Comparative Psychology, 2nd ed. (1970); Peter H. Klopfer (compiler), Behavioral Ecology (1970); W. Sluckin, Imprinting and Early Learning, 2nd ed. (1972); Peter H. Klopfer, Behavioral Aspects of Ecology, 2nd ed. (1973); J. Balthazart, E. Prve, and R. Gilles (eds.), Hormones and Behaviour in Higher Vertebrates (1983); John L. Fuller and Edward C. Simmel (eds.), Behavior Genetics: Principles and Applications (1983); and Katherine Albro Houpt, Domestic Animal Behavior for Veterinarians and Animal Scientists, 2nd ed. (1991). Works that deal with animal cognitive behaviour include Donald R. Griffin, The Question of Animal Awareness: Evolutionary Continuity of Mental Experience, rev. and enlarged ed. (1981), Animal Thinking (1984), and Animal Minds (1992); and James L. Gould and Carol Grant Gould, The Animal Mind (1994).