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.
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 »
The Ultimate Octopus Quiz
An octopus has a relatively evolved brain, strong arms and a unique defense mechanism. Take this quiz and learn about the octopus. See more »
The Ultimate Oyster Quiz
The oyster is a shelled sea creature that lives on the ocean floor. Take this quiz and learn more about the oyster. 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 show images of these mollusks in their natural habitat (not on your dinner plate). Check out these squid pictures. See more »
How Octopuses Work
The two centimeter male pillow octopus is dwarfed by his six-foot female pillow octopus mate. Learn more about the intriguing octopus. See more »
How Squid Work
Squid have been featured in sailing myths and legends for more than 300 years. Learn about squid, squid anatomy and find out what daily life for a squid is like. See more »
How do oysters make pearls?
How do oysters make pearls, and what is the difference between natural and cultured pearls? See more »
Loading more content
Wonder Woman Named Honorary U.N. Ambassador
The Link Between Birth Control and Depression: Should Women Be Worried?
Conspiracy Theories About, Around and From Donald Trump
See More Headlines »