Jamie Gundry’s dramatic image of a white-tailed eagle (Haliaeetus albicilla) on the cover of this book reflects the twisting changes in fortune experienced by this species, with a revival that can be attributed to a successful interplay of science, policy and practice. White-tailed eagles were historically much more widely distributed than they are today (Yalden, 2007), once breeding across much of Europe, but by the early twentieth century the species was extinct across much of western and southern Europe. The main cause of its decline was persecution by farmers and shepherds, who considered the eagles a threat to their livestock, but, along with other raptors, white-tailed eagles were also seriously affected by DDT in the 1960s and 1970s, which had disastrous effects on the breeding success of remaining populations.

In the Anthropocene, when our environment is changing rapidly and the windows of opportunity for action to prevent further biodiversity loss are narrow, conservation researchers are increasingly encouraged to think and operate beyond the traditional approaches of producing peer-reviewed papers and presenting results to other members of the research community. Indeed, the perception that researchers belong in their ivory tower, from which they deliver evidence for others to interpret, disseminate and use in decision-making, is thankfully now widely recognised as outdated. The rise of fake news, a deliberate lack of consideration for scientific evidence, and changes to the ways of assessing the value of researchers’ work probably all play a role in supporting this shift in perception. Moreover, for many researchers, the prospect of their work ‘making a difference’ and having an impact on wider society is at least as great a motivation for doing research as generating new knowledge, however interesting that may be.

INTRODUCTION

The majority of hypotheses proposed to explain the evolution of social monogamy focus on the benefits of biparental care to offspring (e.g., Kleiman, 1977; Wittenberger & Tilson, 1980). This is probably for two reasons. First, most socially monogamous fish, birds and mammals show some form of biparental care; indeed, this association is so close that many early authors included biparental care in their definitions of monogamy (e.g., Lorenz, 1963, p. 167; Lack, 1968, pp. 4-5; Brown, 1975, p. 168; Wilson, 1975, p. 589). Second, given the enormous difference that normally exists between the potential reproductive rates of the sexes (especially in mammals because of female gestation and lactation: Clutton-Brock & Vincent, 1991), it is difficult to explain why the most competitive males are unable to monopolize more than one mate, unless males are constrained by paternal commitments.

Although understandable, this emphasis on the benefits of biparental care has, we believe, shifted the focus of the debate on social and/or genetic monogamy away from its original evolution and onto its current function and maintenance. In this chapter we address this imbalance by considering the origins of social monogamy in mammals. First, we attempt to reconstruct the evolutionary routes by which social monogamy could have evolved, by considering the social and parental care systems that may have been exhibited by non-monogamous ancestors.