Males and females often differ in developmental patterns, adult morphology, ecology and behaviour, and in many mammals males are often larger. Size dimorphism results in divergent nutritional and energetic requirements or reproductive strategies by the sexes, which in turn sometimes causes them to select different forage, use different habitats, and express differing social affinities. Such divergent life-styles often lead males and females to live large parts of their lives separately. Sexual segregation is widespread in animals. Males and females may share the same habitat, but at different times, for example, or they might use different habitats entirely. Why did sexual segregation evolve and what factors contribute to it? Sexual Segregation in Vertebrates explores these questions by looking at a wide range of vertebrates and is aimed as a synthesis of our current understanding and a guide for future research.

There is extensive evidence that vertebrates of all classes have the ability to control the sexes of the offspring they produce. Despite dramatic differences in the mechanisms by which different taxa determine the initial sex of offspring, each group has found its own way of adjusting offspring sex ratios in response to social and environmental cues. For example, stress is a well-known modulator of offspring sex in members of all groups studied to date. Food availability, and limitation in particular, is another common cue that stimulates biases in offspring sex ratios in a wide variety of species. Offspring sex can be adjusted at the primary level, which occurs prior to conception, or at the secondary level, during embryonic development. While the mechanistic pathways that ultimately result in sex ratio biases and the developmental time-points sensitive to those mechanisms likely differ among taxa, the key involvement of steroid hormones in the process of sex ratio adjustment appears to be pervasive throughout. This book reviews the systems of sex determination at play in different vertebrate groups, summarizes the evidence that members of all vertebrate taxa can facultatively adjust offspring sex, and discusses when and how these adjustments can take place.

In this innovative celebration of diversity and affirmation of individuality in animals and humans, Joan Roughgarden challenges accepted wisdom about gender identity and sexual orientation. A distinguished evolutionary biologist, Roughgarden takes on the medical establishment, the Bible, social science—and even Darwin himself. She leads the reader through a fascinating discussion of diversity in gender and sexuality among fish, reptiles, amphibians, birds, and mammals, including primates. Evolution's Rainbow explains how this diversity develops from the action of genes and hormones and how people come to differ from each other in all aspects of body and behavior. Roughgarden reconstructs primary science in light of feminist, gay, and transgender criticism and redefines our understanding of sex, gender, and sexuality. Witty, playful, and daring, this book will revolutionize our understanding of sexuality. Roughgarden argues that principal elements of Darwinian sexual selection theory are false and suggests a new theory that emphasizes social inclusion and control of access to resources and mating opportunity. She disputes a range of scientific and medical concepts, including Wilson's genetic determinism of behavior, evolutionary psychology, the existence of a gay gene, the role of parenting in determining gender identity, and Dawkins's "selfish gene" as the driver of natural selection. She dares social science to respect the agency and rationality of diverse people; shows that many cultures across the world and throughout history accommodate people we label today as lesbian, gay, and transgendered; and calls on the Christian religion to acknowledge the Bible's many passages endorsing diversity in gender and sexuality. Evolution's Rainbow concludes with bold recommendations for improving education in biology, psychology, and medicine; for democratizing genetic engineering and medical practice; and for building a public monument to affirm diversity as one of our nation's defining principles.

The Chang Tang, the vast, remote Tibetan steppe, is one of the most forbidding places on earth. Yet this harsh land is home to a unique assemblage of large mammals, including Tibetan antelope, gazelle, argali sheep, wild ass, wild yak, wolves, snow leopards, and others. Since 1985, George B. Schaller and his Chinese and Tibetan co-workers have surveyed the flora and fauna of the Chang Tang. Their research provides the first detailed look at the natural history of one of the world's least known ecosystems.

"This book is about the differing spatial distribution of males and females in species of hooved mammals. This behavior, wherein males and females live separately for long periods of time, has been observed in many species, but the causes of it remain uncertain"--

This collection of 20 chapters written by leading evolutionary biologists from around the globe provides a fascinating insight into the patterns and causes of differences between males and females in the natural world.