The fish, who live in pitch-black darkness, likely use their bioluminescent lures to find mates. Males then attach themselves to the females—and never let go. Many anglerfish, like the Diceratias ...

During a chaotic period some 50 million years ago, the strange deep-sea creatures left the ocean bottom and thrived by clamping onto their mates. A female anglerfish, with a bioluminescent lure, in ...