Cuttlefish

ocean · shape-shifter · super smart · mollusc

Magical color-changers. Cuttlefish can change their skin color and pattern in milliseconds to hide from predators or sneak up on prey. Scientists still aren't completely sure how they do it, which makes them one of the ocean's greatest mysteries.

Built-in flotation device. Inside their body, cuttlefish carry a special bone called a cuttlebone that works like a submarine's ballast tank. They fill it with gas or water to float up or sink down without any effort.

Weird W-shaped eyes. Cuttlefish have unusual pupils shaped like the letter W, which help them see perfectly in the ocean depths and spot the tiniest movements.

Eight arms plus two bonus tentacles. Unlike octopuses with just eight arms, cuttlefish have eight regular arms PLUS two longer tentacles with sticky suckers that shoot out to grab fish and shrimp for dinner.

Most are fist-sized. Most cuttlefish are about the size of your hand (15-25 cm), but the giant cuttlefish can grow as long as a ruler and weigh as much as a small dog.