Octopuses, along with their cephalopod cousins squids and cuttlefish, are considered to be some of the most intelligent invertebrates out there. They have large brains and are able to quickly master a ...

Octopuses have gotten a reputation for being cunning camouflagers and intelligent creatures. But some are known for a more ominous reason: They're deadly. One group — the blue-ringed octopus (genus ...