How long have nautiluses existed?
According to fossil records, animals similar to the chambered nautilus have existed for about 500 million years. Although no regulations currently exist to protect them, the six living species of chambered nautilus appear to be in decline. A nautilus may live more than 20 years — a very long time compared to other cephalopods. To control its buoyancy, a nautilus pumps fluids in and out its shell chambers, which are connected by a tube called a siphuncle.