What is a "nautilus"?

A nautilus is a cephalopod mollusk known for its distinctive spiral shell. It inhabits deep ocean waters and is considered a living fossil, with a lineage that dates back millions of years. The nautilus has a soft body and multiple tentacles, which it uses for locomotion and capturing prey. Its shell consists of interconnected chambers that provide buoyancy control. The nautilus is a nocturnal creature, typically venturing to shallower depths at night to feed on small fish and crustaceans. It is known for its slow growth rate and longevity, with some individuals living up to 20 years or more. The nautilus is a remarkable and enigmatic creature, representing a unique evolutionary lineage in the animal kingdom.