Cuttlefish

Cuttlefish __ Description & Predation __

Cuttlefish are actually not fish, but mollusks. They range in size from 15 cm to 25 cm. Cuttlefish eat small mollusks, crabs, shrimp, fish, octopuses, worms, and other cuttlefish. Their predators include dolphins, sharks, fish and seals. Cuttlefish has a unique internal structure called the cuttlebone. It helps them so that they don't sink or rise. Cuttlefish can change their color to camouflage themselves from predators. They also camouflage themselves to hunt and sneak up on their prey. They have eight sucker-lined arms and two prehensile tentacles. To catch its prey, it opens its eight arms and shoots out two long feeding tentacles. On the end of each is a pad covered in suckers that grabs and pulls prey toward its beak. The beak allows it to cut open flesh like a pair of scissors, so it can use its tentacles to tear out meat. Feisty! They can light polarity to signal and communicate with marine animals. __ Special Characteristics __ Their skin has three layers of chromatophores (colour pigment cells)- a bright yellow layer near the surface, then an orange-red layer and finally a dark base. Cuttlefish has large W shape pupils and two spots of concentrated sensor cells on their retina or forvea, one to look more forward, and one to look more backwards. They can also reshape their entire eye to change focus. Their blood looks blue-green because it uses the pigment hemocyanin to carry oxygen instead of hemoglobin. They have three hearts: one for each set of gills, and one for the rest of the body. The cuttlefish propels itself by drawing water into a compression chamber and then squeezing it to jet the water out a funnel under the head. Cuttlefish also produces ink, like squids and octopuses, but they only use it as their last resort.

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For some interesting videos on the Cuttlefish visit: http://www.pbs.org/wgbh/nova/camo/