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Odd Couples

Odd Couples: Extraordinary Differences between the Sexes in the Animal Kingdom

Copyright Date: 2013
Pages: 312
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    Odd Couples
    Book Description:

    While we joke that men are from Mars and women are from Venus, our gender differences can't compare to those of other animals. For instance: the male garden spider spontaneously dies after mating with a female more than fifty times his size. Female cichlids must guard their eggs and larvae--even from the hungry appetites of their own partners. And male blanket octopuses employ a copulatory arm longer than their own bodies to mate with females that outweigh them by four orders of magnitude. Why do these gender gulfs exist? Introducing readers to important discoveries in animal behavior and evolution,Odd Couplesexplores some of the most extraordinary sexual differences in the animal world. From the fields of Spain to the deep oceans, evolutionary biologist Daphne Fairbairn uncovers the unique and bizarre characteristics--in size, behavior, ecology, and life history--that exist in these remarkable species and the special strategies they use to maximize reproductive success. Fairbairn describes how male great bustards aggressively compete to display their gorgeous plumage and large physiques to watching, choosey females. She investigates why female elephant seals voluntarily live in harems where they are harassed constantly by eager males. And she reveals why dwarf male giant seadevils parasitically fuse to their giant female partners for life. Fairbairn also considers humans and explains that although we are keenly aware of our own sexual differences, they are unexceptional within the vast animal world.

    Looking at some of the most amazing creatures on the planet,Odd Couplessheds astonishing light on what it means to be male or female in the animal kingdom.

    eISBN: 978-1-4008-4760-0
    Subjects: Ecology & Evolutionary Biology, Zoology, Biological Sciences, Sociology

Table of Contents

  1. Front Matter
    (pp. i-vi)
  2. Table of Contents
    (pp. vii-x)
  3. CHAPTER 1 Introduction
    (pp. 1-8)

    I spent my earliest days as a professional biologist happily tramping through the forests of southern Canada recording the survival, reproduction, and movement patterns of tiny mice that make their living among the detritus of the forest floor. My study subjects were the big-eared, dark-eyed deer mice that so often plague country cabins, apparently preferring the security and constant availability of food in human habitations to the perils of life in the wild. The official motivation for my study was to determine what causes the numbers of mice in a given population to fluctuate over time, and this, in turn,...

  4. CHAPTER 2 The Roots of Sexual Differences: Why Male and Female Animals Differ
    (pp. 9-22)

    To understand why having two sexes seems to work so well for animals, we need to see this curious sexual dichotomy for what it is, a division of reproductive effort into separate male and female roles. A few animals are able to reproduce without sex, and some arehermaphrodites, combining male and female functions in the same individual, but the vast majority of animal species divide their reproductive function into distinct male and female sexes. This allocation of reproductive function, calleddioecy, predominates in animals as disparate as mammals, insects, roundworms, and clams and is clearly the prevalent pattern of...

  5. CHAPTER 3 Elephant Seals: Harems, Hierarchies, and Giant Males
    (pp. 23-45)

    My first encounter with elephant seals occurred on a gray day in early January of 2003 as I was driving down the coast highway in California with my husband, Derek, and daughter, Robin. We were alone on the highway and all enjoying the spectacular cliffs, ocean views, and generally wild country that stretches south from Monterey Bay to Santa Barbara. We came down a smooth sweep of road from the high cliffs of Big Sur to the gentler coastal hills north of Point Conception. The highway curved over to the very edge of the low beach cliffs, and suddenly, on...

  6. CHAPTER 4 Great Bustards: Gorgeous Males and Choosy Females
    (pp. 46-63)

    Great bustards (known to science asOtis tarda) are iconic birds of open, rolling grasslands and agricultural areas across a wide swath of temperate Eurasia.¹ They are huge birds with features reminiscent of both cranes and grouse, and they are most often seen foraging quietly for insects, seeds, and herbaceous vegetation in agricultural fields and fallow areas.² Although they are probably best known for the gorgeous mating displays of their males, the “great” in their name refers not to the impressiveness of those displays but, rather, to the huge size of the adult males (table 4.1). Historical records credit males...

  7. CHAPTER 5 Shell-Carrying Cichlids: Protective Males and Furtive Females
    (pp. 64-80)

    Elephant seals and great bustards represent the extremes of sexual size dimorphism within mammals and birds, and the differences between the sexes in these species are certainly impressive. However, to find extraordinary differences between males and females among vertebrate species, we have to leave the familiar world of large, terrestrial animals and explore the watery lifestyles of fishes. The ray-finned fishes (class Actinopterygii) are the clear vertebrate champions in terms of both the diversity and the magnitude of their sexual differences. At one extreme are species in which females can be hundreds of thousands of times more massive than their...

  8. CHAPTER 6 Yellow Garden Spiders: Sedentary Females and Roving Males
    (pp. 81-103)

    My first encounter with a yellow garden spider occurred quite unexpectedly on a cool September morning as I was clambering up a sandy bank on the edge of an abandoned quarry in southern Quebec. I had been looking down as I scrabbled for handholds on the slippery bank, and I glanced up just as I crested the lip of the quarry. The low morning sun dazzled my eyes, glancing off a fine layer of dew that still lingered on the tangle of early fall herbage. In the midst of this chaotic brilliance, suspended no more than a hand’s breath from...

  9. CHAPTER 7 Blanket Octopuses: Drifting Females and Dwarf Males
    (pp. 104-115)

    Spider biologists argue, with considerable justification, that the extreme sexual dimorphism found in many species of orb-web spiders is the result of females becoming giants rather than males becoming dwarfs.¹ However, in numerous groups of marine animals the epithet “dwarf male” is clearly appropriate.² In some of these species the females may be larger than one might expect when compared to closely related species, but the real standouts are the males. Not only are these fellows tiny when compared to their mates, they are also stripped-down versions of fully functioning, independent adults. In essence these dwarf males have become ultraspecialized,...

  10. CHAPTER 8 Giant Seadevils: Fearsome Females and Parasitic Males
    (pp. 116-132)

    “Giant seadevil” is certainly not a name that inspires affection. One imagines a huge, fearsome animal of some sort, perhaps with a gaping mouth full of hideous teeth to invoke the devilish image. Such an image is not far from the truth. Seadevil is the common name for a diverse group of decidedly unattractive anglerfishes found in the depths of the open ocean. As their name suggests, anglerfishes are predators that capture prey by “angling” with a lure. In most species the lure is suspended on a stalk so that it dangles or wriggles close to its owner’s mouth. When...

  11. CHAPTER 9 Bone-Eating Worms: Female Tubeworms with Harems of Minuscule Males
    (pp. 133-146)

    So far I have described examples of extreme sexual differences in animals that live fully on land (great bustards and garden spiders), partly on land and partly in the sea (elephant seals), in freshwater (shell-carrying cichlids), in the shallow waters of the open ocean (blanket octopuses), and in the vast expanses of the ocean depths (seadevils). In this chapter we descend to the bottom of the ocean to examine the lives of animals that make their living on the sea floor itself . The species described in this chapter, bone-eating worms, come from the segmented worm phylum (Annelida), which also...

  12. CHAPTER 10 Shell-Burrowing Barnacles: Sac-Like Females with Harems of Phallic Males
    (pp. 147-159)

    Barnacles are arthropods, members of that vast phylum comprised mainly of active, many-legged, hard-bodied animals including insects, spiders, crabs, shrimps, centipedes, and millipedes. Unlike most other types of arthropods, however, barnacles are almost all sessile, bottom-dwelling animals that remain anchored in one spot throughout their adult lives. Acorn and gooseneck barnacles are the most familiar barnacle forms and are often found in very high densities on rocks, pilings, ships’ hulls, and even the skins of whales. At low tide you can often find solid mats of these barnacles completely covering the underlying rocks or pier pilings to which they have...

  13. CHAPTER 11 The Diversity of Sexual Differences: Differences between Males and Females across the Animal Kingdom
    (pp. 160-186)

    The examples we have seen, from elephant seals to bone-eating worms, are among the most extreme sexual dimorphisms found in the animal kingdom. As promised, these extraordinary species illustrate the truly amazing diversity of ways in which animals can divide their reproductive roles into male and female functions. However, the extreme differences between sexes in these species are obviously not typical of animals in general. The males and females in most animal species do not differ so starkly. In this chapter I shift gears to ask in what ways male and female animals tend to differ on average. In other...

  14. [Illustrations]
    (pp. None)
  15. CHAPTER 12 Concluding Remarks
    (pp. 187-194)

    The overall patterns of sexual differences summarized in chapters 2 and 11 and the truly extraordinary sexual differences described in the intervening chapters provide rich fodder for thinking about animals and, in particular, for thinking about what it means to be male and female in the animal kingdom. The main impression that I hope you will take away from these chapters is that sexual differences are a major component of the fabric of animal variation. Males and females differ in externally obvious ways in almost all animal classes that contain dioecious species, and in many species the differences are sufficient...

    (pp. 195-196)
  17. APPENDIX A: Scientific Names Corresponding to Common Names Used in the Text
    (pp. 197-202)
  18. APPENDIX B: Summary of Sexual Dimorphisms by Animal Phylum
    (pp. 203-206)
  19. NOTES
    (pp. 207-238)
    (pp. 239-246)
    (pp. 247-286)
    (pp. 287-288)
  23. INDEX
    (pp. 289-300)