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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 do oysters make pearls?

Oysters can create pearls from a single grain of sand. How exactly does an oyster create a pearl, and what is the difference between a natural pearl and a cultured pearl?

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. Watch the footage at HowStuffWorks. See more »

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

Is the Casper octopod at risk from underwater mining? Learn more about the Casper octopod and the risk mining poses in this HowStuffWorks Now article. See more »

Cuttlefish Can Count to Five, New Study Shows

Cuttlefish have an innate number sense that helps them pick a bigger dinner. Learn more about these counting cephalopods at HowStuffWorks Now. See more »

6 Haikus and 3 Limericks About This Googly-eyed Squid

What is the stubby squid? Learn more about this species of cephalopod in this HowStuffWorks Now article. See more »

Fascinating Discovery Reveals How Cephalopod Eyes Detect Color

It turns out cephalopods aren't colorblind. Learn more about how cephalopods see color in this HowStuffWorks Now article. See more »

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

A new look at the sea butterfly snail reveals a surprising case of convergent evolution. Learn more in this HowStuffWorksNow article. See more »

Why is octopus blood blue?

Octopuses have blue blood unlike the red blood of mammals. Find out why scientists think octopus blood is blue at HowStuffWorks. See more »

How can an octopus make itself look like another animal?

Octopus camouflage is essential to survival in the depths of the ocean. Learn how octopus camouflage wards against predators like sharks and rays. See more »

Could a squid take down a submarine?

Giant squid are powerful, enormous creatures that can stretch longer than a full-size school bus. Learn all about giant squid attacks. See more »

Squid Pictures

Squid pictures show images of these mollusks in their natural habitat (not on your dinner plate). Check out these squid pictures. See more »