Nighttime sheep-herders rejoice, for green-glowing sheep are now a thing. Two questions, though. How? And why?
This picture of a glowing cat has not been altered in any way. The cat, on the other hand, has been altered quite a bit. A team of researchers has genetically engineered it to express green fluorescent protein (aka "GFP," originally found in jellyfish), which makes the cat glow green under ultraviolet light.