Argonaut, or Paper Nautilus, an eight-armed mollusk, closely related to the octopus. Argonauts live in the open waters of temperate oceans. They are known for their attractive, paper-thin shells. Since the floating shells resemble small boats, mariners named them after the Argonauts of Greek mythology. Argonauts are primarily drifters but are capable of swimming, using a form of jet propulsion.

ArgonautsArgonauts are small mollusks closely related to octopuses.

Only the female has the characteristic shell, which serves as a shelter for her and as a nest for the eggs. It also provides buoyancy, allowing the animal to float freely. Although the argonaut is not attached to the shell and can abandon it, she spends almost all her life in it. She secretes the shell from the expanded tips of the first pair of arms.

There is a tremendous difference in size between the female and male of each species. In the common Atlantic species, the female is eight inches (20 cm) long and the male one inch (2.5 cm). The male argonaut, which closely resembles a small octopus, has one arm that is much longer than the others. During mating this arm, which contains the sperm, is detached from the male and becomes attached to the female.

What Are Argonauts?

Argonauts (AHR guh nawts) are mollusks that are closely related to octopuses. Female argonauts can grow to more than 18 inches (46 centimeters) in length. Also, the females produce paper-thin shells in which they live and store eggs.

Because of these paper-thin shells, argonauts are sometimes called paper nautiluses. This includes the males, even though they have no shells. Males are also much smaller than females. They grow to only about 1 inch (2.5 centimeters) long.

Argonauts live near the surface of warm seas, where they feed on small fish. The ancient Greeks believed argonauts sailed on the water by using two of their arms as sails. Because of this, they named the mollusk after the sailors of the ship Argo. They were the sailors who went to look for the Golden Fleece with Jason in the famous Greek myth.

Argonauts make up the genus Argonauta. The common Atlantic species is A. argo. Argonauts belong to the family Argonautidae.