The Tiger-striped Nautilus (Nautilus Pompilius), sometimes simply called the Chambered Nautilus, is one of the most iconic marine animals due to its beautiful and distinctive shell. Found mainly in the Indo-Pacific region around Australia, Indonesia, and the Philippines, this nautilus is a type of cephalopod related to octopuses, squids, and cuttlefish. However, unlike its relatives, which lack external shells, the nautilus sports a striking, spiral-shaped shell with distinctive tiger-like brown or reddish bands, giving it its common name.

The nautilus shell has a unique internal structure with chambers, which it uses for buoyancy. As the animal grows, it moves into a larger chamber at the front of the shell, sealing off the smaller, previous chambers. By adjusting the gases and fluids within these chambers, the nautilus can control its buoyancy, allowing it to move up and down in the water column. This adaptation helps the nautilus thrive at depths ranging from shallow coral reefs to around 500 meters (about 1,640 feet), although it primarily stays in deeper, cooler waters during the day and ascends at night to feed.

The Tiger-striped Nautilus is a “living fossil” with little change in its structure over millions of years, which gives scientists insights into ancient marine life. However, it is under threat due to over-collection for its shell, which is highly valued in jewelry and decoration. Conservationists are increasingly concerned about the nautilus population, as it is slow-growing, reproduces infrequently, and thus recovers slowly from depletion.

The intricate structure and resilience of the Tiger-striped Nautilus make it both a marvel of nature and a focus of conservation efforts to protect its place in marine ecosystems.