The common cuttlefish or European common cuttlefish (Sepia officinalis) is one of the largest and best-known cuttlefish species. They are a migratory species that spend the summer and spring inshore for spawning and then move to depths of 100 to 200m during autumn and winter. They grow to 49 cm in mantle length (ML) and 4 kg in weight. Animals from subtropical seas are smaller and rarely exceed 30 cm in ML. The common cuttlefish is native to at least the Mediterranean Sea, North Sea, and Baltic Sea, although subspecies have been proposed as far south as South Africa. It lives on sand and mud seabeds and it can tolerate brackish water conditions. Predators Cuttlefish only have a lifespan of 1–2 years (captive and wild) and have many predators including sharks, dolphins, seals, fish, and cephalopods which includes other cuttlefish. They have many defensive mechanisms to help protect them from predators including a siphon which they can use to shoot water out of to propel them away from danger, ink which can distract and disorient a predator as the cuttlefish escapes, and their camouflage abilities which can help them avoid predators altogether. A 2008 study on S. officinalis revealed that cuttlefish embryos, if visually exposed to a certain species of prey (e.g. crabs), will hunt primarily for that prey in later life. S. officinalis usually prefer shrimp to crabs, but when the embryos were exposed to crabs and the embryos had hatched, the young cuttlefish switched preferences and proceeded to hunt the crabs more often than the shrimp. Diet During the day, most cuttlefish can be found buried below the substrate and fairly inactive. At night however, they are actively searching for prey and can ambush them from under the substrate. Cuttlefish are carnivorous and eat a variety of organisms including crustaceans (crabs and shrimp), small fish, molluscs (clams and snails), and sometimes other cuttlefish which is more commonly seen when the abundance of other prey is low. Anatomy The common cuttlefish is one of the largest species of cuttlefish with their mantles (does not include their head and arms) reaching upwards of 45 cm. The mantle houses the reproductive and digestive tracts of the cuttlefish and is also home to an internal shell called the cuttlebone. The common cuttlefish has two highly developed eyes, eight arms which are located around the mouth and are used to hold and move