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Cephalopods: Diverse and Distinct

Cephalopod Awareness Week is the perfect time to celebrate the diversity of these highly-intelligent creatures.

Published October 10, 2018

Cephalopods, meaning “head-foot,” get their name from the limbs attached to their head, making this class of marine mollusk quite recognizable. The head is home to all the cephalopod’s internal organs, including the stomach and ink sac.

Stumpy cuttlefish

Stumpy cuttlefish 

Members of the cephalopod class include octopuses, nautiluses, cuttlefishes and squids. There are more than 800 identified species of cephalopods around the world, inhabiting every one of the Earth’s oceans. This variety of marine mollusk has been around for ages and can be traced back to more than one million years ago.

Cephalopods are a very diverse class and come in all shapes and sizes. The giant Pacific octopus can grow up to 600 pounds, while the chambered nautilus only reaches about 8 inches. All species of cephalopods are known for their abilities to quickly adapt and react to overcome the challenges of living among the ocean’s fiercest predators.

Cuttlefish are sometimes described as the chameleons of the sea. Species like the stumpy cuttlefish can change their skin color and texture in a split second to avoid detection by predators.

Big fin reef squid

Big fin reef squid 

Cuttlefish and squid both have eight short arms and two long tentacles (octopuses are equipped with just eight arms), but key similarities end there. The cuttlefish moves a bit slower and its body is broader than the squid, which has a thinner, sleeker body. Perhaps the most interesting difference lies in the eyes: squids tend to have large, oval pupils, apparent especially in the big fin reef squid, and cuttlefish have W-shaped pupils.

No matter their shape, size, speed or abilities, we do know that all cephalopods deserve appreciation every week of the year!

Stay tuned during Cephalopod Awareness Week to learn more about these amazing animals!

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