Here are 10 animals that have some of the highest levels of testosterone and the impact it has on their behavior and characteristics.

A new study on mayflies of the genus Ecdyonurus illustrates just how multifaceted and surprising reproductive behavior in ...

Researchers found a rare, strictly binary brain feature in mice that is permanently active in females but completely dormant in adult virgin males, only turning on after males mate. ( ...

Across the animal kingdom, sound is more than communication—it's a signal of survival and success. From birds and primates to insects, fish, and amphibians, animals broadcast acoustic "advertisements" ...

Sometimes it’s scary to think that the many species we see today might not be around in twenty years. Or, if we don’t focus ...

Using computer tomography, insect researchers at the State Museum of Natural History in Stuttgart have analysed the mating ritual of mayflies in detail.

Have you ever heard two or more women say they’re on the same cycle? This is a common claim among women who live together, for example in a family or as housemates. This idea that people menstruate, ...

In the deep ocean, where sunlight never reaches, and food drifts down like confetti, survival is less about speed and more ...

A brain-invading worm spread by rats and snails is making inroads into the United States. A study this week seems to show the ...

A "dominant" crocodile-like predator with a big lump on its head preyed on man's ancestors three million years, ago, according to new research. Early humans - embodied by the iconic hominin Lucy - ...

This week's Outside Story shows how fishers, normally solitary creatures, ever so briefly meet each other during mating season.