Mammal Societies

Tim Clutton-Brock

• Publisher: Wiley-Blackwell
• Year: 2016
• ISBN:
  9781119095361
• Edition: 1
• Topic: Ciencias biológicas
• Subtopic: Zoología

The book aims to integrate our understanding of mammalian societies into a novel synthesis that is relevant to behavioural ecologists, ecologists, and anthropologists. It adopts a coherent structure that deals initially with the characteristics and strategies of females, before covering those of males, cooperative societies and hominid societies. It reviews our current understanding both of the structure of societies and of the strategies of individuals; it combines coverage of relevant areas of theory with coverage of interspecific comparisons, intraspecific comparisons and experiments; it explores both evolutionary causes of different traits and their ecological consequences; and it integrates research on different groups of mammals with research on primates and humans and attempts to put research on human societies into a broader perspective.

Chapter 1
Social Evolution

Nothing in biology makes sense except in the light of evolution.

Theodosius Dobzhansky

1.1 Origins

Life is full of dangers, competition for resources and reproductive opportunities is universal and all life forms need to be well adapted to the physical and social environments they occupy in order to grow, survive and breed. While an appreciation of the adaptedness of animal behaviour extends back into antiquity, the modern understanding of adaptation as a consequence of natural selection originates with the work of Darwin (1859, 1871) and Wallace (1870, 1878). In the Origin of Species Darwin reviews the diversity of animal adaptations for survival while in The Descent of Man he focuses to a greater extent on the evolution of reproductive adaptations as well as on human evolution.

The fundamental importance of Darwin's theory in explaining variation in the morphology, physiology and behaviour of animals was quickly appreciated by his contemporaries. ‘If you ask whether we shall call this the century of iron, or of steam, or of electricity’, wrote Ludwig Boltzman in 1886, ‘then I can answer at once with complete conviction: it will be called the century of the mechanistic understanding of Nature – the century of Darwin’ (Boltzman 1905).

But it wasn't. After Darwin's death, scientific attention focused on developmental questions rather than functional ones and his holistic view of biological adaptation was eclipsed by the growth of other biological sub-disciplines. As a result, the true century of Darwin was delayed for nearly 100 years, and is not yet over.

When functional questions were considered in the years following Darwin's death, they mostly related to anatomical adaptations to the physical environment. Before the 1930s, systematic studies of the behaviour and ecology of animals in natural populations were scarce and most were the work of naturalists, sociologists or philosophers who lacked Darwin's theoretical structure, his compelling interest in principles and his readiness to confront apparent exceptions. In many cases, they were satisfied with accurate descriptions of the biology of particular species coupled with ad hoc explanations of the function of particular traits. One important exception was the work of entomologists, like Fabre, who could not ignore the social behaviour of insects and who began to describe the form and structure of colonies and speculate about the mechanisms that maintained them (Fabre 1879; Cézilly 2008).

Only after 1930 did a substantial number of professional biologists start detailed studies of the behaviour and ecology of animals in their natural habitats and, when they did, their principal objective was seldom to explain their evolution or to account for their diversity. They fell into four main groups. First, there were systematists and faxonomists whose principal interest was in phylogeny and development but who found themselves confronted with the obvious diversity of animal societies. Second, there were the founding fathers of animal behaviour, including Julian Huxley, Konrad Lorenz, Niko Tinbergen, Karl von Frisch, T.C. Schneirla and Bill Thorpe. Though their research sometimes encompassed functional aspects of behaviour (especially foraging behaviour), with the exception of Niko Tinbergen, their primary focus was on questions concerning the control and development of behaviour. Third, there were animal ecologists, including Luc Tinbergen, David Lack and A.F. Skutch, whose interests included the regulation of animal populations and the evolution of life-history parameters and who faced the need to explore the role of territoriality and competition between breeding pairs. Finally, there were the population geneticists, including Ronald Fisher and J.B.S. Haldane, whose principal focus was on the operation of natural selection and the evolution of genetic systems but whose interests inevitably included dispersal and the genetic structure of local populations as well as the evolution of demographic measures. Unlike many of the others, they were well aware of the evolutionary problems raised by social behaviour, though these were tangential to their main interests.

The development of field research after 1930 rapidly revealed the diversity of breeding systems and social behaviour and raised questions about the adaptive significance of these differences. Many of the earliest studies involved insects or birds, since they were relatively easy to observe and their nests are often accessible (Lack 1935; Skutch 1935; Tinbergen 1935). Most birds are monogamous and biparental so that the diversity of social organisation was not a topic of immediate interest. The first professional studies of social behaviour in mammals also date from the 1930s (Figure 1.1). Zuckerman (1929, 1932) explored the social and sexual behaviour of captive baboons and related these to physiological processes, while Fraser Darling's studies of red deer and grey seals (Darling 1937a,b, 1943) and C.R. Carpenter's research on howler monkeys, macaques and gibbons (Carpenter 1934, 1935, 1942) described the size and structure of groups and the reproductive behaviour of individuals and were more concerned with contrasts in ecology.

Figure 1.1 Early studies of the behaviour of mammals. In the 1930s, (a) Frank Fraser Darling investigated the social and reproductive behaviour of red deer and grey seals, (b) Solly Zuckerman explored the sexual behaviour of captive baboons, and (c) Clarence Ray Carpenter established field studies of several primates, including howler monkeys, spider monkeys, rhesus macaques and gibbons. Sources: (a) © http://littletoller.co.uk/authors/frank-fraser-darling/; (b) Reproduced with permission of Zuckerman Archive, University of East Anglia; (c) © Smithsonian Institution Archives. Image SIA Acc. 90-105 [SIA2008-0362].

After 1945, studies of animal ecology and animal behaviour proliferated. In America, which still possessed extensive state forests and national parks, a larger proportion of ecological research was directed towards wildlife management, while in Europe the primary objectives of ecological research were more fundamental in nature. Ecological research focused on foraging behaviour, on the mechanisms regulating population density and on the proximate and ultimate factors influencing life-history parameters, including clutch size, laying data and survival (Lack 1954, 1966). While a substantial proportion of behavioural research was directed at investigating the causation and development of behaviour (Lorenz 1950; Tinbergen 1951; Hinde 1966), a substantial number of studies (mostly of birds) examined feeding behaviour, foraging strategies, territoriality and the benefits of sociality (Tinbergen 1952; Gibb 1954; Hinde 1956), laying the foundations for later work on optimal foraging behaviour (Krebs 1978). However, few studies had yet monitored the breeding success of individuals throughout their lifespans and little was known of the extent or causes of variation in fitness in natural populations in either sex.

As field studies of birds developed and proliferated, it became obvious that there were striking contrasts in their social behaviour which were consistently related to ecological differences (Orians 1961; Lack 1968). In particular, J.H. Crook's research on weaverbirds showed that there were systematic relationships between variation in social behaviour and contrasts in ecology: species living in open savannah or semi-arid habitats formed the largest breeding colo...

Table of contents

• Cover
• Title Page
• Copyright
• Preface
• Acknowledgements
• Chapter 1: Social Evolution
• Chapter 2: Female Sociality
• Chapter 3: Female Dispersal and Philopatry
• Chapter 4: Female Mating Decisions
• Chapter 5: Maternal Care
• Chapter 6: Social Development
• Chapter 7: Communication
• Chapter 8: Competition between Females
• Chapter 9: Cooperation between Females
• Chapter 10: Mating Systems
• Chapter 11: Association between Males
• Chapter 12: Male Dispersal and its Consequences
• Chapter 13: Reproductive Competition among Males
• Chapter 14: Relationships between Males in Multi-Male Groups
• Chapter 15: Males and Females
• Chapter 16: Paternal Care
• Chapter 17: Cooperative Breeding
• Chapter 18: Sex Differences
• Chapter 19: Hominins and Humans
• Chapter 20: Human Behaviour
• Index
• End User License Agreement