Many bird species are monogamous. However, genetic studies have shown that the social partner is often not the genetic father of all offspring. Some studies found biased sex ratios: more males than ...

Same-sex sexual behavior has been documented in over 1,500 animal species. It occurs across virtually all major groups — from ...

Primates are a group of mammals that includes humans and our close relatives, such as apes, monkeys and lemurs. Monkeys, such as capuchins and macaques; prosimians, like lemurs and tarsiers; lesser ...

Differences among the DNA of seven ape species—including humans—are greater than originally thought, according to an ...