The Mystery of the Seashell-shaped Argonaut Case!

Argonauts are cousins of the octopuses. For years biologists have been confused as to how the Argonauts utilize their delicate white coloured seashell-shaped cases. Only the female Argonaut grows this special structure, which can grow up to about 30cm. The male Argonaut is surprisingly only the size of a female’s eye! The mystery surrounding this bizarre structure however has now been solved!

Female Argonauts…

When at the surface of the water gather air into their case and then disappear down into the depths of the sea. Recent studies suggest that this structure is used to trap air bubbles which help the creatures maintain their buoyancy at a desirable depth.

How does it work?

At the surface of the water they position their body to trap the air inside the shell-like case, and once at a certain depth, the water pressure will naturally seal the air within the shell, leaving the Argonaut free to float and become quite agile in this comfort zone!

Is that all?

The case does have another important function though. It acts as an Egg-case where a large number of eggs can be stored. The male is often found inside the female case with the eggs.

Image via: Wired