Nautilus Overview

The nautilus is the oldest cephalopod at 5 million years old and is the only cepalopod with an exterior shell. Their shells average eight inches in diameter and are stripped and smooth. Each male nautilus has 90 slim tentacles with no suckers and a large eye, while females only have 50 tentacles. Although their arms are less powerful than other cephalopods they are so numerous they can easily overpower prey. Most live to be 15 years old. Nautiluses reproduce annually. It takes 9 months to a year for them to hatch. The nautilus lives in tropical waters, coral reefs by day and deeper waters by night. They eat hermit crabs, crustacean's exoskeletons, and small fish. Octopods, sharks, triggerfish, and sea turtles prey on them. But the real predator they need to watch out for are humans. The nautilus is endangered because of its beautiful shell.