Many people are under the impression that a reef squid and cuttlefish are one and the same marine creature. This is perhaps because the two creatures look very similar. However, mistaking one for the other is a mistake that amateur biologists make, as this could not be further from the truth. While both the reef squid and cuttlefish are mollusks and cephalopods, the former belongs to the order tuethida, whereas the latter belongs to the order sepiida. Hence, knowing the difference between reef squid and cuttlefish will help a person distinguish between these two marine invertebrates.

Reef squids are relatives of the cuttlefish and inhabit all the oceans around the world. Some of them live close to the shore, but majority inhabit the waters far from land and usually prefer to stay in the deep salt water. Reef squids have ten arms that they use for propulsion as well as for catching their prey. They have mantle on top of the head which houses their gills, stomach, reproductive organs, digestive system and the famous ink sac. The reef squid has 2 large and complex eyes; eight arms that are short in size; and two arms that are long. These arms, which are referred to as tentacles, have suckers that help the squid catch its prey. The arms are situated around the mouth, in a circle. In addition, the reef squid also has fins running along the length of its body and by moving these fins, they can swim.

The hood or mantle of an adult reef squid can reach a length between 12 to 20 centimeters. Propulsion is achieved by expelling water from a cavity located within the mantle via a funnel. This allows the reef squid to move forward fast in the water.

The squid is has a mottled coloring, which can range from brown to green on its upper surface and a lighter coloring is present on the lower surface. This coloring helps to protect the squid from predators. If it is still found by predators, the squid releases ink from its ink sac and uses that as a covering to retreat into the surrounding reef.

Squids feed on mollusks, small fish and crustaceans. They use their radula to chew on their prey, which are caught with the help of the 2 long tentacles.

On the other hand, the cuttlefish is bigger in size compared to the reef squid. It is around forty-five centimeters in length. The cuttlefish also has a mantle that houses its cuttlebone, digestive system and reproductive system. It has a set of fins running along the entire body which when moved helps the cuttlefish to swim. Just like the reef squid, the cuttlefish has eight small arms and 2 longer arms.

However, the cuttlefish has special cells in its skin that allows it to change its color and texture of the skin. The cuttlefish uses ink that it emits into the water to confuse a predator that is going to attack it. Unlike the reef squid, the cuttlefish has a shell inside its body that is referred to as cuttlebone. This bone is composed of calcium carbonate and plays a vital role in providing buoyancy to the creature. The bone has several small chambers inside, which can be filled with gas to alter the buoyancy.

The cuttlefish is common in the Mediterranean Sea, North Sea and Baltic Sea. Rather than occupying deep depths like the reef squid, cuttlefish prefer the sub-littoral depths, ranging from the low tide area to the start of the continental shelf, which is usually 200 meters deep.

It goes without saying that the reef squid and cuttlefish are two different species of cephalopods and should not be mistaken for one another.

More Articles :

• Difference Between Reef Squid And Cuttlefish
• Giant Squid Facts
• Life Cycle Of Squid
• What Does A Vampire Squid Eat ?
• What Does Giant Squid Eat ?

MarineBio: Reef Squids
http://marinebio.org/species.asp?id=286