Sepia esculenta
Sepia esculenta, more commonly known as the golden cuttlefish, is a member of the genus "Sepia" and family Sepiidae. Cuttlefish are in the class Cephalopoda and phylum Mollusca. This is a species of cuttlefish that ranges from the Russian seas to the Philippines and throughout the western pacific. This species of cuttlefish is a nektobenthic organism living with a range of depths between 10m-150m(33ft-492ft) but is primarily found within the shallow, coastal waters from japan to the Philippines at a depth between 10m-100m. Members of this species are roughly 18cm in length. Body plan. Golden  cuttlefish have 8 arms and 2 arms. Contrary to octopus who use their arms to move and grab objects in their surroundings, cuttlefish use their 8 arms to grab onto and move prey towards the beak that was caught by the 2 longer tentacles. The beak of the golden cuttlefish is nestled at the base of the 8 arms, used to bring prey towards the beak. Additionally, the beak is used to bite and protect itself from predators. The cuttlefish has highly developed eyes, and is able to change the shape of their eye to adjust its lenses. Their eyes  are capable of detecting polarized light, which increases their ability to see contrast, despite being color blind. Like other species of cuttlefish, the golden cuttlefish has an internal shell called a cuttlebone. The cuttlebone controls the buoyancy of the cuttlefish, as they can fill with gases to perfect their buoyancy within the water column. Life cycle. The life span of the golden cuttlefish is typically short and around 1 year. After maturity, males perform different visual displays to attract a potential mate to sexually reproduce. These members of the Cephalopoda class are gonochoric, meaning reproductive organs are separate between males  and females. Males carry sperm and females carry eggs. In cuttlefish, to carry out mating, males pass a packet of sperm using one of their arms specially adapted for this purpose to the females buccal membrane. Golden Cuttlefish male sperm competition plays a large role in reproduction. Females often mate with more than one male during each mating season and retain sperm in storage for a long time. This leads to male competition to mate and eventually sperm competition to fertilize the eggs. Golden cuttlefish males use their arms to scrape the packets of sperm from other males off the  buccal membrane, in an effort to remove as much as possible before adding their own. Once completed, the female golden cuttlefish will lay clusters of eggs at a pace of one egg roughly every 5 minutes on seaweeds, grasses, branches, etc. Batches consist of 50-300 eggs for roughly 3-4 followed by a day of rest. This patterns continues until thousands of eggs have been laid. Once mating is complete, golden cuttlefish return to the sea. When the eggs are hatched, golden cuttlefish start out in a planktonic stage for a period of time before growing larger and taking  up a benthic lifestyle. Swimming. Like other cuttlefish, the golden cuttlefish generally swims by using the side fins. By rippling their fins, they can swim, crawl, and hover in the water. When in danger, they have the ability to suck water into their body cavity and release it through an extension that acts like a funnel, propelling the golden cuttlefish forward quickly away from danger. Feeding and camouflage. Cuttlefish, along with octopus, have the largest brains of all invertebrates, relative to body size. The size of their brains rival that of some reptiles and even some mammals. The increased brain  size of cuttlefish allows them to preform complex actions and behaviors. One such behavior is the ability to change the pattern of the skin to camouflage into their surroundings or disorient a potential prey item or predator. Cuttlefish have specialized skin cells called chromatophores. These specialized cells are present in other organisms like squids and octopus. Chromatophores are organs in the skin that contain pigment sacs that can become more or less visible based on muscles expanding or contracting the pigment within the skin. Cuttlefish have millions of chromatophores all over their bodies, and using their brains, can control the  pigment of each individual chromatophore to create any pattern or blend into their surroundings. By doing so, cuttlefish are able to completely alter their visible appearance very quickly and effectively vanish from predators or prey in an instant. Cuttlefish change their appearance/camouflage in order to be able to sneak up on prey. They can also creates waves of vibrant colors and patterns to hypnotize their prey and then strike. Using two tentacles that shoot out from beneath the eyes, they pull prey into the beak to consume. Just like other cuttlefish, the golden cuttlefish feeds primarily on other small  mollusks, decapod crustaceans, shrimp, octopus, worms, and even other cuttlefish occasionally. Common predators of cuttlefish include dolphins, sharks, larger fish, seals, eels, and other cuttlefish. When threatened, the cuttlefish will jet away using its siphon and release black or reddish brown colored ink to deter and temporarily confuse potential predators, allowing the cuttlefish to escape.