Nautiloids are marine cephalopods that belong to the class Cephalopoda. They are characterized by their coiled, chambered shells, which provide buoyancy and protection. Nautiloids have existed for over 500 million years, making them one of the oldest living groups of animals. Today, the Nautilus is the only surviving genus, with several species found in the Indo-Pacific region. These creatures have a simple body structure, with tentacles extending from their heads. Nautiloids are known for their ability to navigate the ocean using jet propulsion, expelling water from their shells. Their unique shells are often studied in paleontology, providing insights into the evolution of marine life.