Mammals usually produce approximately equal numbers of sons and daughters, but there
are exceptions to this general rule, as has been observed in ruminant ungulate species …

Females can benefit from mate choice for male traits (eg sexual ornaments or body
condition) that reliably signal the effect that mating will have on mean offspring fitness …

This comprehensive introductory text integrates evolutionary, ecological, and demographic
perspectives with new results from field studies and contemporary noninvasive molecular …

Why are men, like other primate males, usually the aggressors and risk takers? Why do
women typically have fewer sexual partners? In Why Sex Matters, Bobbi Low ranges from …

Over the last several decades, mathematical models have become central to the study of
social evolution, both in biology and the social sciences. But students in these disciplines …

Evolutionary theory predicts that mothers of different condition should adjust the birth sex
ratio of their offspring in relation to future reproductive benefits. Published studies …

Trivers and Willard's suggestion that natural selection favors maternal control of offspring
sex ratio in relation to maternal condition has been much debated. The theoretical …

Elephants have fascinated humans for millennia. Aristotle wrote of them with awe; Hannibal
used them in warfare; and John Donne called the elephant “Nature's greatest masterpiece …

We present results of a 10-year study of free-ranging gray-footed chacma baboons (Papio
ursinus griseipes) in the Okavango Delta of Botswana. The majority of deaths among adult …

BACKGROUND: Literature describing temporal variation in the secondary sex ratio among
humans reports an association between population stressors and declines in the odds of …