A new study posits that same-sex sexual behavior developed to help primates in complex social groups ease tension, reduce ...

This has been quite the wild year in human evolution stories. Our relatives, living and extinct, got a lot of attention—from ...

While many studies have looked at possible evolutionary links between men's strength and sexual behavior, a Washington State University study included data on women with a surprising result. Women, as ...

Scientists have traced kissing back to early primates, suggesting it began long before humans evolved. Their analysis points to great apes and even Neanderthals sharing forms of kissing millions of ...

As early humans spread from lush African forests into grasslands, their need for ready sources of energy led them to develop a taste for grassy plants, especially grains and the starchy plant tissue ...

Biologists tend to look at the animal kingdom and try to categorize things in an organized fashion. But nature has a way of ...

Prologue -- The structure of this book -- Six paradigms -- 1. Introduction -- Some premises -- Some history -- Evolution and modification of behavior -- Evolution of ontogeny in the human animal -- ...

The act of kissing may have started long before modern humans existed, a new modeling study suggests. Kissing stretches back roughly 21 million years, to the shared ancestor of humans and other large ...