Cuttlefishes (Sepia officinalis) are classified as Cephalopoda which also includes squid, octopuses and nautiluses but despite their name, they are not fish but molluscs. They have an internal shell – the cuttlebone, large W-shaped pupils, eight arms, and two tentacles furnished with denticulated suckers, with which they secure their prey. They generally range in size from 15 cm to 25 cm and can be seen in the Lagoon between beach and Reef Crest. Cuttlefishes eat small molluscs, crabs, shrimp, fish, octopuses, worms, and other cuttlefishes. Their predators include dolphins, sharks, fish, seals, seabirds and other cuttlefishes. Their life expectancy is about one to two years. Cuttlefishes are sometimes referred to as the "chameleon of the sea" because of their remarkable ability to rapidly alter their skin color at will. Cuttlefishes change color and light polarisation to communicate to other cuttlefishes and to camouflage themselves from predators.