See more of our trusted coverage when you search. Prefer Newsweek on Google to see more of our trusted coverage when you search. In a bizarre twist of evolution, some fish have been found to be able ...

Scientists have uncovered the secret of the Amazon molly, an all-female fish species that has survived for 100,000 years through cloning, defying long-held evolutionary theories.

In the natural world, the disappearance of males is usually considered a death sentence for a species. Yet one tiny fish has spent the last 100,000 years proving evolution wrong. Swimming through the ...

In many fish species, water temperature determines the sex of the fry. This biological mechanism threatens to wipe out entire populations because of a shortage of females in the face of global warming ...

The animal kingdom is full of unique names. We often use special words to tell males and females apart. For example, a male lion is a king, while a female is a lioness. We call a male deer a buck and ...

Female mosquitofish are not only bigger than the males, they have bigger impacts on freshwater ecosystems. In a controlled study conducted in experimental ponds, researchers found dramatic differences ...

Female fish can breed a new species if they aren't choosy about who is Mr. Right. Fish will mate with a species outside their own if the male's coloring is attractive enough or if the female can't see ...

Chronic exposure to microplastic fibers causes aneurysms, erosion of surface layers and other serious damage to fish gills, and increases egg production in female fish, a sign that chemicals in the ...