When is a fish? Just looking at him, a cuttlefish seems very similar to any other fish as he swims around a tank or through the ocean. He has a head and eyes and a body lined with small, delicate-looking fins that propel him through the water. However, despite its similarity in appearance to an ordinary fish, the cuttlefish is much more similar to an octopus and is classified as a mollusk.
While fish have organs called swim bladders that fill with gas and help them stay afloat, cuttlefish use a gas-filled bone known as the cuttlebone.
“The bone is within the body part of the animal called the mantle and attached to the mantle is ahead with eight arms and two feeding tentacles” (Dunlop, 2007). This means of maintaining neutral flotation is as unique as the cuttlefish’s means of locomotion. While it appears to swim with the aid of delicate-looking fins that line its sides much like the fish uses its fins top and bottom to help propel it through the water, the cuttlefish has a much different means of movement. “The cuttlefish propels itself using a series of spurts, drawing water into a compression chamber which it squeezes to jet the water out a funnel under the head. Direction changes can be made by swiveling the nozzle of this funnel and narrowing the funnel controls speed” (Weston, 1997). Thus, while it appears quite simple, the cuttlefish is a very complex animal just in its propulsion and buoyancy system alone.
However, the cuttlefish has many more surprises, the first becoming clear when it goes to feed. Quite different from the fish whose mouth is nearly always visible and sometimes is lined with small teeth, the cuttlefish snares its prey by first opening out the eight arms that surround its mouth and extending one or both of its feeding tentacles, each of which have strong suckers on the end to ensure the prey does not escape. Like an octopus, the cuttlefish has a strong, parrot-like beak that it uses to cut through the strong shells of its preferred food sources (Weston, 1997).
Finally, the cuttlefish is a master of disguise. “Its skin is covered with special cells called chromatophores, iridophores and leucophores that reflect light in many different colors enabling the cuttlefish to blend into its background almost perfectly” (Dunlop, 2007). According to Weston (1997), when the cuttlefish gets excited, it begins flashing through a series of yellow, red-orange, and blue-green colors while Dunlop (2007) indicates it can change its texture as well its color to more fully blend into its surroundings. Should its camouflage prove unsuccessful, however, the cuttlefish retains one more defense in its ability to eject ink. “The predator would get a mouthful of ink that tastes nasty and coats its nostrils” (Dunlop, 2007).
Despite its name or common understanding, a closer examination of the cuttlefish reveals that it is anything but a fish. A fascinating creature that exists naturally more in the UK than in America, the cuttlefish is more accurately thought of in terms of an octopus and continues to amaze aquatic enthusiasts with its startling abilities.
Works Cited
- Dunlop, Colin. “Cuttlefish Basics.” Tonmo. (2007).
- Weston, Paula. “Fascinating Cuttlefish.” Answers in Genesis. (1997). Web.