This is a science project I had to do on the nautilus. I guess its kinda interesting if you want to know more about nautiluses. Also, if you have to research nautiluses you would not beleive how hard info is to get on them. Sorry if the picture mislead you that is NOT what a nautilus looks like, but triond doesn’t have any pictures of nautiluses.
The Chambered Nautilus
Some call the nautilus a living fossil. Why? According to fossils, the nautilus has virtually unchanged for more then 400 million years. They reached their evolutionary peak between 400 and 500 million years ago when the nautilus today evolved from the straight shelled nautilus. About 500 million years ago, nautiluses were the only really large animal to be able to swim above the sea floor. The strongest animal of their day, the nautilus could really eat anything that it could overcome.
The Life Cycle
The average life span for a nautilus is 15-20 years, making the nautilus the most long lived kind of cephalopod in existence. It all starts when the egg is laid. The nautilus egg is more then an inch long, the largest egg laid by an invertebrate. When the baby nautilus hatches, it is 1.2 inches on average. The juvenile then takes several years to reach sexual maturity. In its shell, it keeps growing chambers, each bigger then the last. It starts with about 7 and then grows to about 30. After the young nautilus reaches sexual maturity, they mate only once every year. Then, the females have about a dozen eggs fertilized and deposits them either one at a time or in small groups throughout the year. Little is known about the life cycle of the nautilus. No one knows where they release their eggs in the wild, exactly when they reach sexual maturity, and a nautilus has never been raised from hatching to death due to natural causes in captivity. Also, a nautilus has never been tracked for its entire life in the wild.
The body of the nautilus is held in a shell and comprised of 30 different chambers. Most of the organs are held in the main chamber and the opening to the outside of the shell. There are 90 tentacles with no suckers in the opening, along with the mouth and radula, a structure with nine teeth used for feeding. The nautilus also has two pairs of gills. Both the digestive and the circulatory system are closed. One of the most amazing things about the nautilus is its shell. It can completely retract itself inside it, it’s pressure resistant up to 800 m below sea level, and camouflaged with its coloring.
The nautilus protects itself with its strong external shell. When in danger, it can completely retract itself inside it and cover itself with the hood of the nautilus. Some of its predators include sharks, turtles, octopuses, and triggerfish. They all can penetrate the nautiluses shell.
Little is known about the communication of nautiluses. They go through on mating season every year, which can last for up to 24 hours, and that is all that is known about how they interact with each other. Most of this is due to the fact that they have never been tracked for their entire lifetime, and they have never lived a full life in captivity.
The nautilus is a carnivorous creature that feeds off of small fish, crustaceans, and shrimp. Due to the low energy amounts that the nautilus puts out during swimming, it only needs to eat once a month. To eat it needs to rise from its normal depth of 300 m to 100 m. How it eats is by capturing its food in its tentacles.
The nautilus has adapted to the environment that it lives in by getting a pressure resistant shell, a way of swimming and a way of walking on the seabed or dry land. They have not needed to adapt much because where they live (the indo-pacific region on the slopes of the coral reefs) is much like where they have lived in the past.