Animals have evolved many different ways of protecting themselves, from prickly quills and razor-sharp teeth to clever camouflage and sturdy shells. Now, scientists have discovered a surprising new technique that appears to be a defense mechanism: Some male octopuses use venom to avoid being eaten by their female mates.

Learn more about the mating of blue-lined octopuses - a treacherous ordeal involving sex, cannibalism, and sedation.