Species Fact Profile: Chambered Nautilus (Nautilus pompilius)

Chambered Nautilus

Nautilus pompilius (Linnaeus, 1758)

Range: Tropical Indo-Pacific Oceans
Habitat: Coral Reefs, Ocean Depths
Diet: Fish, Crustaceans, Carrion
Social Grouping: Semi-Social
Reproduction: Sexually mature at 15-20 years old.  Males use a set of tentacles to transfer a packet of sperm to the female.  About a dozen eggs, each 3 centimeters long, laid once per year.  Unlike other cephalopods (octopus, squid, cuttlefish), nautiluses do not have a larval stage; the young hatch from the eggs already encased in a shell.  Also unlike other cephalopods, they can breed multiple times over the course of their lives
Lifespan: 20 Years
Conservation Status: CITES Appendix II

• Shell length of up to 20 centimeters; the shell grows throughout the animal's life, adding chamber after chamber to the spiral-shaped shell and residing in the largest, outermost one.  An adult's shell may have 30 chambers
• A tube called the siphuncle runs through the shell, releasing gas to maintain buoyancy and keep the nautilus upright
• The shell is often (incorrectly) claimed to demonstrate the so-called golden spiral, a logrithmic ratio of growth.  In reality, nautilus shells do not grow in this fixed perfect pattern
• Primarily active by night.  It has poor vision, as its primitive eye has no lenses.  Swim by contracting muscle, steer by feeling for obstacles (or bumping in to them).  When not swimming, cling to rocks
• Food is seized by the ninety-some tentacles protruding from the shell, then pulled in to the parrot-like beak where it is crushed
• Predators include octopuses, sharks, triggerfish, and sea turtles
• Two subspecies - the larger emperor nautilus (N. p. ppompilius) and the much smaller Sulu nautilus (N. p. suluensis), restricted to the Sulu Sea of the southwestern Philippines
• Considered a living fossil, having existed in approximately its current form for over 400 million years.  Once there were thousands of nautilus species in the oceans.  Now only a few remain.
• Hunted for their shells, which are used for ornamentation (including as cups)and as a source of mother of pearl.  Also collected (to lesser extent) for live aquarium trade