SOCIAL BEHAVIOUR IN ANIMALS

actions of animals living in communities. Such behaviour may include the feeding of the young, the building of shelters, or the guarding of territory. Additional reading General works that deal with social behaviour include W.C. Allee, The Social Life of Animals (1938, reprinted 1976), a readable classic emphasizing peck order and social facilitation at the expense of other aspects of social behaviour; Niko Tinbergen, Social Behaviour in Animals, with Special Reference to Vertebrates (1953, reissued 1990), a popular account by a founder of ethology concentrating on birds, fish, and insects; John Tyler Bonner, Cells and Societies (1955, reissued 1966), a readable account of social life from the howler monkeys down to the cell; William Etkin (ed.), Social Behaviour and Organization Among Vertebrates (1964), a set of moderately technical articles on social behaviour; John F. Eisenberg, The Social Organizations of Mammals, Handbuch der Zoologie, 10:192 (1965), a review of mammalian social behaviour that shows it derives mostly from maternal societies; Peggy E. Ellis (ed.), Social Organization of Animal Communities (1965), a useful set of rather technical articles, concentrating on social behaviour in insects; John Hurrell Crook (ed.), Social Behaviour in Birds and Mammals (1970), several excellent technical summaries of research in social behaviour, including a discussion of habitat and society; Stuart J. Dimond, The Social Behaviour of Animals (1970), a discussion of experiments on the learning of social behaviour in domestic and caged animals; E.S.E. Hafez (ed.), The Behaviour of Domestic Animals, 3rd ed. (1975), an excellent sourcebook, containing chapters on patterns and mechanisms of behaviour and the specific behaviour of cattle, sheep, swine, horses, dogs, cats, and poultry; Trevor B. Poole, Social Behaviour in Mammals (1985), a condensed source of information on mammalian sociobiology for advanced readers; Andrew Cockburn, Social Behaviour in Fluctuating Populations (1988), a critique of hypotheses and ideas concerning the influence of demography on the evolution of social behaviour in animals; Thomas D. Brock et al., Biology of Microorganisms, 7th ed. (1994); and Robert D. Barnes, Invertebrate Zoology, 6th ed. (1994).Texts that cover particular types of behaviour are V.C. Wynne-Edwards, Animal Dispersion in Relation to Social Behaviour (1962, reissued 1972), a polemic reviewing much of social behaviour to support the view that animals practice birth control by means of social behaviourbut control is usually by agonistic reactions; Harriet L. Rheingold (ed.), Maternal Behaviour in Mammals (1963), a set of moderately technical articles on the mother-infant relationship in mammals; and Edward C. Simmel, Ronald A. Hoppe, and G. Alexander Milton (eds.), Social Facilitation and Imitative Behaviour (1968), scientific articles on imitative learning in animals and humans.Symbiosis is examined in S. Mark Henry (ed.), Symbiosis, 2 vol. (196667), informative summaries of a few of the many symbioses known to occur, from viruses to humans; and Lynn Margulis, Origin of Eukaryotic Cells (1970), a discussion of the origin of cells by symbiosis.Studies on the social behaviour of various specific animals include Niko Tinbergen, The Herring Gull's World: A Study of the Social Behaviour of Birds, rev. ed. (1961, reprinted 1989); David Lack, Ecological Adaptations for Breeding in Birds (1968, reissued 1972), a demonstration that the social behaviour of nesting birds depends on their habitats and their foraging; Martin L. Cody (ed.), Habitat Selection in Birds (1985), an excellent collection of review articles; F. Fraser Darling, A Herd of Red Deer (1937, reissued 1967), one of the earliest field studies of a wild society, establishing that deer are matriarchal; John Paul Scott and John L. Fuller, Genetics and the Social Behaviour of the Dog (1965), a scientific analysis of heredity and learning that shows how they interact; Irven Devore (ed.), Primate Behavior (1965), one of the best collections of relatively nontechnical articles on the behaviour of free-living monkeys and apes; Frans de Waal, Chimpanzee Politics: Power and Sex Among Apes (1982; originally published in Dutch, 1982), an entertaining and perhaps humbling look at coalition building, power plays, deception, and manipulation in a species other than our own; and Gisela Kaplan and Lesley Rogers, Orang-utans in Borneo (1994), covering the debates surrounding the orangutan and questions relating to communication, the use of tools, and learning abilities, based on the authors' fieldwork observations and incorporating all previous fieldwork results as well as past laboratory tests. Dynamics of social behaviour Costs and gains Social behaviour among humans is often regarded as an end in itself, the expression of a basic drive that has no necessary purpose. Biologists doubt that any animal has social tendencies without some adaptive advantage. The costs Social behaviour and communication not only take an animal's substance and energy; they impede feeding, drinking, and other inputs necessary for life. The first cells that associated with other cells to form multicellular filaments lost the ability to absorb on the side by which they were attached. Perhaps the reason most multicellular filaments occur among animals that are attached to the ground or to some other surface is that such animals lose less proportionately than members of free-floating aggregations; attachment on one side to the ground already limits their input. Locomotion is impaired if animals must stay together. The single-celled ciliates could not readily have evolved into higher organisms, because dividing them into many joined cells would have slowed down these fast-moving predators. A speedy golden plover trying to stay with other shorebirds in a mixed flying group near shore constantly turns back to keep with them; it is impeded by its social tendency. Social behaviour also attracts enemies. Groups of animals have epidemics, while solitary animals seldom do. Many disease-carrying parasites spread much more easily at times when animals are together. Some rabbit fleas are even adapted to the hormonal cycles of the rabbits, so that they reproduce at the times of year the rabbits are reproducing and hence are social. Predators, like parasites, often have an easier time if animals are crowded together; the animals are often busy reacting to each other and the predator can sneak up without being observed. Their communicatory systems may even attract predators. Tuna prey specifically on fish in schools; a small hawk in tropical America (Accipiter superciliosus) mainly on mixed bird flocks. Social behaviour increases the number of interactions between animals and thus the chances of conflict. The conflicts may be solved by fighting, by patterns of dominance and submission (peck orders), or by mutual avoidance. Mutual fighting and mutual avoidance have the same resulta partitioning of resources for which the animals are competing. Types of animal societies To understand social behaviour more fully, it is necessary to examine it throughout the range of animal life. W.C. Allee, in his classic book The Social Life of Animals, distinguishes two major types of animal societies. One is the parental, or familial, society, in which parent and offspring stay together for varying lengths of time. The other is the pair bond, or club, society, composed of individuals that come together from different families. This type was much emphasized by the 19th-century English philosopher Herbert Spencer because it corresponded to his social Darwinist ideas. The social Darwinist does not like to admit that a weak son can win out if he has powerful parents; but recent work with rhesus monkeys shows clearly that the son of a high-ranking mother tends to be protected by his mother and hence gets to the top of the hierarchy even if he himself is a weakling. Parental societies are very common. Parental societies Parental societies are found at all levels, from the cell to the monkey troupe. All animals provide for their young in some way. In every animal there is a period when the young is part of the parent and receives materials from the parent. Later, the young may partly or completely separate from the parent; in some animals, the more or less separate young is then helped by the parent, or helps it.