Squid Squid Squid are cephalopods in the order Teuthida with elongated bodies, large eyes, eight arms and two tentacles. Like all other cephalopods, squid have a distinct head, bilateral symmetry, and a mantle. They are mainly soft-bodied, like octopuses, but have a small internal skeleton in the form of a rod-like gladius or pen, made of chitin. Squid can change colour for camouflage and signalling. Some species are bioluminescent, using their light for counter-illumination camouflage. Squid are members of the class Cephalopoda, subclass Coleoidea. The squid orders Myopsida and Oegopsida are in the superorder Decapodiformes (from the Greek for "ten-legged"). Two
Colossal squid Colossal squid The colossal squid ("Mesonychoteuthis hamiltoni", from Greek "mesos" (middle), "onycho" (claw, nail), and "teuthis" (squid)), sometimes called the Antarctic squid or giant cranch squid, is believed to be the largest squid species in terms of mass. It is the only known member of the genus "Mesonychoteuthis". It is known from only a few specimens, and current estimates put its maximum size at long and weighing possibly up to , based on analysis of smaller and immature specimens, making it the largest-known invertebrate. Unlike the giant squid, whose arms and tentacles have only suckers lined with small teeth, the