Octopuses, squid, and cuttlefish.
Test your knowledge with these top questions!
What fish does the mimic octopus resemble while moving quickly over open sand?
The mimic octopus folds its arms into a leaf-shaped wedge and undulates like a local banded sole.
How does a mimic octopus copy a banded sea snake?
Six arms thread into a hole while two banded arms rise, curl, and undulate like a sea snake.
How do nautilus tentacles grip prey without suckers?
Grooves and ridges on nautilus tentacles carry glue-like mucus, helping the animal hold prey and reef surfaces.
How does a nautilus enlarge its shell as its body grows?
At the shell opening, the nautilus builds a larger chamber, then seals the former living space behind it.
What makes a nautilus eye unusual among cephalopods?
Instead of a lens, a nautilus eye uses a tiny pinhole opening to project an image onto its retina.
Which body part do male cuttlefish use to transfer sperm packets?
A specialized arm called a hectocotylus places sperm packets, or spermatophores, on or in the female.
Octopus blood turns blue because of which oxygen carrier?
Octopus hemocyanin uses copper atoms to carry oxygen, making oxygenated blood appear blue.
What does a cuttlefish's internal cuttlebone mainly control?
The cuttlebone's many chambers help a cuttlefish stay at different depths with little effort.
What do a giant squid's two long tentacles mainly do?
Rows of suckers help each long tentacle grip prey before the eight shorter arms pull the catch inward.
Vampire squid's internal shell evolved into what shape?
The plate resembles a squid's pen, an internal support that stiffens a squid's mantle rather than a chambered shell.