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.

Some male octopuses tend to get eaten by their sexual partners, but male blue-lined octopuses avoid this fate with help from one of nature’s most potent venoms

Male blue-lined octopi (Hapalochlaena fasciata) have been found to use venom on their sexual partners, as well as for the usual reasons of defense against predators and subduing prey. Killing the females would be counterproductive,

Scientists have found that male blue-lined octopuses inject venom and paralyse females during sex to avoid being killed and cannibalised by their much larger partners. The male octopus of this species precisely injects a dose of its deadly tetrodotoxin venom into the females to immobilise them during copulation,