Sepia officinalis, Cuttlefish [+]

Kingdom Animalia Phylum Mollusca Class Cephalopoda Order Sepiida Family Sepiidae Genus Sepia species: Sepia officinalis [+ITIS +WoRMS]

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Description & Behavior

The amazing European or common cuttlefish, Sepia officinalis (Linnaeus, 1758), reaches a maximum mantle length of 45 cm, although one individual has been recorded at 60 cm. The mantle (main body region above the eyes) houses the cuttlebone, reproductive organs, and digestive organs. A pair of flat fins span the entire length of the mantle, and they undulate rapidly when cuttlefish swim. The head is located at the base of the mantle, with two large eyes on either side and sharp beak-like jaws in the center. The jaws are encircled by eight pairs of arms and two longer tentacles for capturing prey that can be retracted completely into the body. Adults can be recognized by the white lines branching from the base of the flared third arms.

The basic coloring of the common cuttlefish varies, although it typically displays a mottled black or brown color. Color changes are possible due to three types of structures contained within its skin, called chromatophores, leucophores and iridophores, which are small structures filled with colored ink which can be expanded and contracted to communicate with others or form patterns and textures used as camouflage often mimicking the surrounding landscape. These structures allow the cuttlefish to reflect a myriad of colors, and even change the textures of their skin.

The name Sepia refers to the type of ink it houses within its body. This ink is used to deceive large predators when they try to attack the cuttlefish. When a predator is near, the ink is shot out into the water to confuse the predator, while the cuttlefish swims (jets) to safety.

Cuttlefish (Sepiida) are in an Order of mollusks that possess an internal shell called the cuttlebone. The cuttlebone is made of calcium carbonate and plays a dominant role in these mollusks' buoyancy; it is divided into tiny chambers in which the cuttlefish can fill or empty of gas, depending on its needs. They are in the Class Cephalopoda which is the group that contains cuttlefish, octopuses, squid, and nautiloids such as the chambered nautilus.

World Range & Habitat

The common cuttlefish, Sepia officinalis, has been found in the Mediterranean, North and Baltic Seas, although populations have been proposed to occur as far south as the South Africa. They are found in sublittoral depths, at around 200 m.

» GBIF occurrence data in Google Earth [Tips] | Ocean Biogeographic Information System (OBIS) (World Distribution) [about]

Feeding Behavior (Ecology)

The common cuttlefish, Sepia officinalis, is a master of disguise. Its highly specialized array of color-changing structures allow it to blend itself perfectly into the background. This lets it sneak up on prey and shoot out its two long tentacles at lightning speed, which have suckers on the widened pads at the tips. It uses these suckers to grab a hold of its prey and bring it back towards its beak. The common cuttlefish eats crustaceans and fishes. Cuttlefishes primary predators are large fish like sharks, monkfish, and swordfish.

Life History

The reproductive cycles of cuttlefish occur year round, with spikes in mating during the months of March and June. Cuttlefish are dioicous, meaning they have separate male and female sexes. The males transfer sperm to the females via a hectocotylized arm (an arm modified for mating). Cuttlefish have large eggs, 6-9 mm in diameter, that are stored in the oviduct, which are then deposited in clumps on the bottom of the sea. The eggs are colored with ink, which helps them to better blend into the background. The young hatch with a nutritious yolk that will support them until they are able to secure food for themselves. They hatch at a much further developed stage than an octopus does and immediately start feeding on suitably small shrimps.

Conservation Status/Additional Comments

Many people would like to keep cuttlefish as pets. This is quite easy in the UK and Europe as species of cuttlefish like Sepia officinalis the 'European cuttlefish' are found there.

In the US however, there are no naturally found species and the most commonly imported species is from Bali called Sepia bandensis which is a poor traveler and normally arrives as a four-inch adult with perhaps only weeks to live. It is not recommended as a pet. - TONMO.com