May 28, 2013
The chambered nautilus (Nautilus pompilius), a cephalopod, is a relative of squid, octopuses, and cuttlefish. It inhabits ocean waters close to the seafloor in the tropical Pacific during the day and migrates to shallower water at night in search of food, including shrimp, crabs, and fishes. This vertical migration can cover up to 1,200 feet.
The nautilus’ shell is divided into compartments. As the animal grows, it adds compartments, which it uses to regulate its buoyancy and travel up and down the water column. It sucks in and expels water to control forward, backward, and sideways movement. The nautilus can completely withdraw its body into its shell, closing the opening with a leathery hood. Adult nautiluses reach up to 10 inches in diameter and can live for more than sixteen years. The eyes of a nautilus are poorly developed compared to the complex ones of most other cephalopods. The simple, pinhole eyes lack lenses and probably form blurry images at best.
Nautiluses are present in the fossil record 500 million years ago, predating the existence of dinosaurs on Earth. The Aquarium has several chambered nautiluses on exhibit in Wonders of the Deep. Look for them in the cylindrical tank in an exhibit describing vertical migration.