Gray and green eye colors are the rarest in the world. Eye color is determined by the amount of melanin in the iris, with more melanin making eyes darker. A genetic mutation 10,000 years ago caused ...

Cat-like eyes show up in searches everywhere. If the internet is this obsessed with eye color, how rare are green eyes in humans? They're uncommon enough that seeing them still feels like spotting a ...

Forbes contributors publish independent expert analyses and insights. I write about biodiversity and the hidden quirks of the natural world. For most of human history, green eyes didn’t exist.