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The ecology and behavior of the four species of Rhinopithecus, snub-nosed monkeys, are rapidly becoming well known. New field studies reveal in depth the striking adaptations of these colobines. Diets range from those typical for tropical colobines to diets dominated by lichens. The monkeys form bands, at times consisting of more than 400 individuals; these bands are based on the one-male, multi-female units common in colobines. We review the diet, range use, and social organization of snub-nosed monkeys, and then explore the power of socioecological theory to explain their multilevel social organization.Snub-nosed monkeys represent an ecological array, from the Tonkin snub-nosed monkeys (Rhinopithecus avunculus) of tropical forests in Vietnam to the black snub-nosed monkeys (Rhinopithecus bieti) of temperate conifer forests in China. The step-wise gradation of environments provides for a step-wise gradation of behaviors, making this array particularly informative. Further, the harsh environments of black snub-nosed monkeys and golden snub-nosed monkeys (Rhinopithecus roxellana), in which snows are common in winter, put their adaptations in stark relief. Snub-nosed monkeys are useful in understanding the behavioral flexibility of primates, as well as in investigating the influence of environment on both feeding ecology and social organization.

Homosexuality presents a paradox for evolutionists who explore the adaptedness of human behavior. If adaptedness is measured by reproductive success and if homosexual behavior is nonreproductive, how has it come about? Three adaptationist hypotheses are reviewed here and compared with the anthropological literature. There is little evidence that lineages gain reproductive advantage through offspring care provided by homosexual members. Therefore, there is little support for the hypothesis that homosexuality evolved by kin selection. Parents at times control children's reproductive decisions and at times encourage children in homosexual behavior. There is therefore more support for the hypothesis of parental manipulation. Support is strongest, however, for the hypothesis that homosexual behavior comes from individual selection for reciprocal altruism. Same-sex alliances have reproductive advantages, and sexual behavior at times maintains these alliances. Nonhuman primates, including the apes, use homosexual behavior in same-sex alliances, and such alliances appear to have been key in the expanded distribution of human ancestors during the Pleistocene. Homosexual emotion and behavior are, in part, emergent qualities of the human propensity for same-sex affiliation. Adaptationist explanations do not fully explain sexual behavior in humans, however; social and historical factors also play strong roles.

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The lucrative, illegal trade in tigers (Panthera tigris) remains a major conservation problem. Tiger farming has been proposed as a potential solution, with farmed tigers substituting for wild tigers. At first glance, this argument's logic seems simple: farming will increase the supply of tigers, prices will fall, and poaching will no longer be profitable. We contend, however, that this supply-side argument relies on mistaken assumptions. First, tiger markets are imperfect, meaning they are dominated by a few producers who control price. Second, consumers prefer wild tigers to farmed tigers and therefore the two are not pure substitutes. In economic terms, products from wild tigers are luxury goods, commanding a price premium. Third, there is no evidence that farmed tigers can be produced or sold more cheaply than wild tigers. In sum, it is unlikely that farming will drive down the price of wild-caught tigers or decrease profitability for tiger poachers. Rather, tiger farming is more likely to increase aggregate demand for tiger products and stimulate higher levels of poaching.