Cephalopods, or inkfish, are the most intelligent, largest, and mobile of all mollusks. Cephalopods are characterized by their body symmetry, prominent head, and set of at least eight arms or tentacles. Cephalopods earned the nickname inkfish because of their common ability to be able to squirt ink. There are two existing groups of Cephalopods: Coleoidea and Nautiloidea; Coleoidea has internalized their molluscan shell while Nautiloidea still has an external shell. Cephalopods live only in marine environments and are predatory creatures. Cephalopods are capable of changing color and they usually change color in complex patterns as part of courtship behavior.
The main way cephalopods move is through a form of jet propulsion. They do so by drawing water into their mantle cavity and over their gills. Once the cephalopod wants to move it contracts the muscles of the mantle cavity, and water is squeezed out with enough power to propel itself in the desired direction.
Cephalopods are predators and are not picky carnivores. Cephalopods typically eat crustaceans, fish, bivalves, jellyfish, and even other cephalopods. They tend to hunt at the surface of water at night without the threat of predators seeing them. Once the sun rises, they go down to deeper and darker water.
Mating for cephalopods is an event that only happens once in their life, as they both die shortly after mating. When females are ready to mate, they will display a certain color. The male will mate with her by placing his sperm in the female’s pallial cavity, with a tentacle called the hectocotylus. The female cephalopod then lays the fertilized eggs.
