The ancestors of squid and octopus used shells as a form of defense. Pupils learn how cephalopods evolved without shells and the adaptations required to survive without one. Viewers learn how scientists know about these changes and the...

How long does it take a New Reporter to define the word squid? He uses the word squid in a sentence, defines the word, and explains why particular animals are not squids.

During The Great Dying, 90 percent of life in the ocean died. A video lesson from the PBS Eon series describes how the oceans recovered. Viewers learn how some species adapted and thrived while others became extinct.

Cephalopods, including squid, use their color-changing skin for both camouflage and communication. A video explains how squid camouflage themselves in the open ocean with nothing else around. It shows how they mimic the interplay of...

Cuttlefish are actually not fish — they are relatives of the octopus, squid, and nautilus! Scholars explore this concept and more as they observe cuttlefish and their ability to change their coloring through chromatophores. Viewers...

When someone cuts the nerves from a squid brain to the skin, something unexpected happens with the tiny pouches of colored pigment, called chromatophores. Emily takes you behind this phenomenon, and how it can be explained and modeled on...

Hank introduces us to the "simplest" of the animals, complexity-wise: beginning with sponges (whose very inclusion in the list as "animals" has been called into question because they are so simple) and finishing with the most complex...

The squid's body plan has developed for fast action. The shell is reduced to a thin "pen." The mantle wall has elastic fibers that intensify the jet propulsion. Giant nerves allow a fast reflex and three hearts pump oxygen to the gills....

An animation showing that molluscs' basic body plan includes a foot for mobility; a mantle that secretes a shell and a radula for eating. Learn that molluscs today show many variations on this original body plan. An abalone escapes a sea...

In recent years, Humboldt squid have been spotted in increasing numbers off the coast of California. We'll talk about the invasion of the jumbo squid, and possible causes for the phenomenon.

In less than a second, cephalopods can change the color, pattern and shape of their skin.