A nautilus is any of the various species within the cephalopod family Nautilidae. This is the sole extant family of the superfamily Nautilaceae and the suborder Nautilina. It comprises nine living species in two genera, the type of which is the genus Nautilus. Nautilus eggs are similar in size, shape and appearance to a bulb of garlic, a newly hatched nautilus wears a shell divided into seven or eight small chambers. Due to their smaller size and chill lifestyle, the Nautilus only use a single heart to keep them going. Unlike other cephalopods, nautiluses are relatively long-lived, reaching ages of 15 to 20 years, or more. They grow slowly, maturing around 10 to 15 years of age, and produce a small number of eggs that require at least a year-long incubation period. Nautilus are opportunistic carnivores but they hunt at night, feeding on shrimp, crabs, fishes, dead animals, and occasionally another nautilus. It is believed that prey is detected by smell since the animal lacks good vision. Food is captured by its retractable tentacles and passed to its mouth where a beak-like jaw tears it into pieces. The nautilus' natural predators include octopus, sharks, triggerfish, and grouper. The chambered nautilus primarily lives on or near reefs in the western Pacific Ocean and in parts of the coastal Indian Ocean, including near National Marine Sanctuary of American Samoa and Rose Atoll Marine National Monument.