Mantis shrimp or stomatopods are marine crustaceans, the members of the order Stomatopoda. They are neither shrimp nor mantids, but receive their name purely from the physical resemblance to both the terrestrial praying mantis and the shrimp. They may reach 30 centimetres (12 in) in length, although exceptional cases of up to 38 cm (15 in) have been recorded. The carapace of mantis shrimp covers only the rear part of the head and the first three segments of the thorax. Mantis shrimp appear in a variety of colours, from shades of browns to bright neon colours. Although they are common animals and among the most important predators in many shallow, tropical and sub-tropical marine habitats they are poorly understood as many species spend most of their life tucked away in burrows and holes.