Nautilus

The genus Nautilus is one of the most iconic and ancient genera in the animal kingdom, made up of shelled cephalopods that have remained virtually unchanged for over 500 million years. These deep-sea creatures are the last living representatives of a once-diverse group of externally shelled mollusks, and are often referred to as “living fossils.” With their elegant, spiral shells, slow pace, and mysterious deep-ocean habits, Nautilus species offer a rare window into the past, surviving mass extinctions and dramatic shifts in the planet’s ecosystems while retaining much of their prehistoric charm.

Members of Nautilus are found in the tropical Indo-Pacific, especially around the Philippines, Indonesia, Papua New Guinea, Australia, and Fiji. Their most famous feature is their chambered shell, which is not only a protective home but also a natural buoyancy device. As the animal grows, it adds new, larger chambers to its shell and seals off the older ones. These chambers fill with gas and fluid, allowing the nautilus to float or sink like a built-in submarine—a remarkable adaptation for such an ancient animal.

One of the most surprising things about Nautilus species is how different they are from their cephalopod relatives like octopuses, squids, and cuttlefish. Unlike those fast-swimming, short-lived cousins, nautiluses are slow movers, use primitive pinhole eyes without lenses, and can live for 20 years or more. They have around 90 slender, sucker-less tentacles, which they use to catch crustaceans, small fish, and organic debris. They don’t hunt quickly or with intelligence like an octopus—they use stealth and patience, slowly drifting through the dark waters and using smell and touch more than sight to find food.