Large cephalopods frequently make a living by hunting for small ones.
Cannibalism is fairly common among cephalopods.
It occurs in all groups, from Nautilus to cuttlefish and octopuses. Cuttlefishes in captivity show tolerance for each other only when they have been raised together. Most squids are only found in schools of roughly equal-sized individuals. A very specific type of cephalopod predation occurs in several Indo-Pacific octopuses. Around the world, octopuses hunt for snails by drilling a small hole in their shell and injecting a poison.