Scientists have long focused on quantifying fear and other negative emotions in animals. Now they’re trying to measure positive feelings — and it’s a challenge.

New Horizons' enormous 3.0 update, Nintendo is reviving its real-life aquarium tour, which will return to the same U.S.

While exploring a polluted creek, I noticed movement that immediately seemed out of place. What I found were exotic aquarium fish surviving in contaminated water, far from the environments they’re ...