Guppies have been a separate species for 500,000 years, and during that time their color has changed drastically. But one thing has stayed the same: an orange patch on males. This is quite possibly ...

Tiny fish called Trinidadian guppies turn their eyes black to warn other fish when they are feeling aggressive, new research shows. Tiny fish called Trinidadian guppies turn their eyes black to warn ...

The more colorful males were up to two times more sexually active than other guppies. By Laura Baisas Published Jul 10, 2025 3:00 PM EDT Get the Popular Science daily newsletter💡 Breakthroughs, ...

Here’s another advantage of having a big brain: you know how to choose the hottest mates. As it turns out, female guppies with bigger brains are smart enough to prefer attractive male guppies. Their ...

A variety of animals have male-specific ornament traits and these ornaments are favored by female choice. Which male traits are preferred by females often varies among females. Genetic mechanisms that ...

When Robert Heathcote dips his head into the rivers of Trinidad, he’ll often see little black dots moving through the water, even when it’s murky. Those dots are the eyes of small, inch-long fish ...

Tiny fish called Trinidadian guppies turn their eyes black to warn other fish when they are feeling aggressive, new research shows. A study led by the University of Exeter, in collaboration with the ...