Nautiluses are sea creatures - they are cephalopods, which means they are related to octopuses, squids and cuttlefish. Like these they have soft, squishy bodies and plenty of tentacles. Unlike the others, nautiluses have a hard spiral shell like a snail which protects them from predators.
There are a number of different species of chambered nautilus, the most well-known being Nautilus pompilius. All the species live in the tropical waters of the eastern Indian and western Pacific Oceans, in the deep waters around coral reefs.