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Mollusks are members of the invertebrate phylum Mollusca and contain more than 100,000 species. Some mollusks have shells like clams and snails, while larger mollusks have no bones at all like the cuttlefish, squid and octopus.

How Squid Work

Squid have been featured in sailing myths and legends for more than 300 years. They're swift, agile and surprisingly intelligent creatures with brains larger in proportion to their bodies than most fish and reptiles have. Learn about all squid, squid anatomy and how big squid can can actually get.

Watch Cuttlefish Brawl Over a Mate in Unprecedented Video

In the first-ever video of its kind, two male cuttlefish in the wild go head-to-head over a coveted mate. See more »

Humanity's Smartphone Cravings Could Doom Mysterious 'Casper' Octopod

Mining rare minerals from the breeding ground of these newly discovered creatures could endanger their habitat. But hey, then we get batteries. See more »

Cuttlefish Can Count to Five, New Study Shows

When it comes to food, cuttlefish are pros at picking the more filling meal. See more »

6 Haikus and 3 Limericks About This Googly-eyed Squid

Despite its cartoonish visage, yes, this is a real animal. This recently spotted stubby squid was so charming he inspired poetry. See more »

Fascinating Discovery Reveals How Cephalopod Eyes Detect Color

Scientists until recently believed Octopuses & Co. were colorblind. If that were the case, how could the animals create such vivid physical color displays? See more »

Tiny Underwater Snails Fly Through Water Using Same Physics as Winged Insects

The sea butterfly snail moves in Arctic waters in the same way as fruit flies through tropical air. This case of convergent evolution was uncovered by a new study. See more »

Why is octopus blood blue?

Unless you've butchered an octopus, you might assume that it's as red-blooded as you are. And you'd be wrong. Why are octopuses the original blue bloods? See more »

How can an octopus make itself look like another animal?

Imagine that someone is pursuing you down a dark alley. Do you run? Duck behind a trash bin? The mimic octopus doesn't sweat this kind of scenario: It just shape-shifts to disguise itself. You'll be surprised by the tricks it's got up its tentacles. See more »

Could a squid take down a submarine?

Giant squid are aggressive creatures that prey on almost anything that comes their way. How big do these monsters of the sea get, and could they really take down a watercraft? See more »

Squid Pictures

Squid are actually mollusks is although they look much different from their relatives the gastropods (snails) is and bivalves (clams). Check out this image gallery to learn more interesting squid facts. See more »