Cuttlefish Have W-Shaped Pupils

Japanese researchers recorded the deep-sea giant squid off the Ogasawara Islands.

With no bones, the only hard part of an octopus is its beak, so it can slip through tiny openings.

The dark cloud confuses the predator's vision and, in some species, dulls its sense of smell.

Its relatives date back roughly 500 million years, and it is the only cephalopod with a chambered outer shell.