The chambered nautilus is an amazing creature. Unfortunately, it is sought after for its beautiful coiled whitish shell lined with tan markings and and shiny interior. Some people keep them in salt water fish tanks. I don’t encourage collecting any living seashells, in fact it is usually against the law.
The species encountered near Australia can be almost 11 inches long. Often you will find pictures of the shell sliced down the middle to show the swirl of “chambers” inside.
The cephalopod begins it’s life with 4 chambers and builds a new chamber to move into as it outgrows the old and then uses these chambers to fill, or empty, with sea water to control it’s buoyancy.
It hides in the deep in the ocean during the day and will rise at night to eat. The coloring of the shell – white underneath and irregular dark stripes on top – help to camouflage it from predators. During the day, while it’s down near the ocean floor, a predator will have a hard time seeing the Nautilus because of the dark, striped top part of the shell, which is likely to blend with it’s surroundings.
Likewise, at night, as the Nautilus rises toward the surface, if prey is circling below, the white underneath part of the shell will more readily blend with the lighter ocean water. This effect is called “countershading” and it applies to many forms of sealife including penguins and dolphins.
Oliver Wendall Holmes was apparently inspired by this creature and wrote a poem entitled, “The Chambered Nautilus”.
The Chambered Nautilus is an interesting mollusk called a cephalopod. Like the squid, octopus and cuttlefish, the nautilus’s head is attached to it’s feet or foot, but unlike them, it has a complete shell to cover it. The shell appears similar to a snail shell, but inside it is divided into “chambers” which hold gas to keep the animal buoyant. He will add water to the inner chambers when he needs to dive deeper and let it out to float. An adult will have about 30 chambers in it’s shell. It is believed that they can live up to 20 years!
With very poor eyesight, the nautilus depends on it’s sense of smell to hunt for food. It has a crushing beak which allows it to feed on shrimp and crabs, along with fish, which it catches with it’s 90 (approx.) tentacles, but since it exerts little energy to live and move, it only needs to eat about once a month!
It uses a tube to expel water- jet propulsion- which moves it along to move from place to place. The nautilus will dive deep during the day- to depths of 1800 feet- to avoid predators and rise back up during the night to feed on the reefs.
You will not find a nautilus shell lying on the beach- at least it seems very unlikely- and I do not own one. The photos here came from deegolden’s Store at Zazzle.
They can be found living among coral reefs in the Indian and Pacific Oceans and a full grown nautilus can reach 8 inches in length.
In some places the nautilus population is declining because of the popularity of it’s shell and to save this creature, most of the sites I visited urged consumers to not support the harvesting of the nautilus by purchasing a nautilus shell.