Animal · Philippines, Indonesia, Australia
Chambered nautilus
Nautilus pompilius — the name this animal has in the language scientists everywhere share.
The chambered nautilus drifts along steep reef walls in a coiled shell that is divided inside into about thirty sealed chambers. By pumping gas and liquid between them it can hang almost weightless in the water, the way a submarine does.
Picture credit: Hans Hillewaert (CC BY-SA 4.0) · Hans Hillewaert (CC BY-SA 4.0) · Wikimedia Commons
Where does the chambered nautilus live?
Home: steep coral-reef slopes in deep, dark water.
In the wild it lives in these countries: the Philippines, Indonesia, Australia, Papua New Guinea, Fiji, Vanuatu, Palau, Japan.
Conservation status from the IUCN: vulnerable.
The short profile
Fully grown: shell up to 20 cm across. It weighs about 1 kilograms. On the menu: meat.
The story behind it
When night falls, the nautilus rises up the reef slope out of the deep to look for crabs, shrimp and bits of food that have sunk to the bottom. About ninety thin tentacles reach out in front of it; they have no suckers, but grooves that are sticky enough to hold a meal. Its eyes are surprisingly simple, with no lens at all, just a tiny opening like a pinhole camera, so the world it sees is blurry. Smell matters much more to it, and it can track a scent from a long way off. The animal built its shell itself, chamber by chamber, and always lives in the newest and largest one. A thin cord called the siphuncle runs through the older chambers, shifting liquid and gas so the nautilus can set its own buoyancy. Because it grows slowly and does not breed until it is ten or fifteen years old, a population that has been fished hard takes a very long time to recover.
Find it on the globe
Chambered nautilus is there as a tiny animated figure that breathes and looks around. From far away the planet is only a blue ball; detail arrives as you zoom in, and this one appears once you are close enough. Open it on the globe.
It sits at its real coordinates, not near them — the same numbers listed in the facts above. Switch off the layer for this kind of place and it disappears again; the buttons for that are down the right-hand edge.
Questions children ask
How big does a chambered nautilus get?
Its shell grows to about 20 centimetres across, roughly the size of a side plate, and the whole animal weighs around a kilogram. The soft body fills only the last and biggest chamber; all the rest of the shell is empty space.
Where do chambered nautiluses live?
They live in the western Pacific and the eastern Indian Ocean, around places such as the Philippines, Indonesia, Palau and the Great Barrier Reef. By day they stay several hundred metres down on the reef slope, and they climb into shallower water at night.
Why is the nautilus called a living fossil?
Shelled relatives of the nautilus swam in the sea hundreds of millions of years ago, long before the dinosaurs, and left huge numbers of fossils behind. Today's nautiluses still look much like those old shells, which is why people give them that nickname.
Where these numbers come from
Every figure on this page was checked against public reference sources before publication. Where sources genuinely disagree, the text says so.
Last checked: