The cuttlefish is an amazing, world-wide-living, cephalopod.  These invertebrates have eight tentacles on the front of their body; these are all the same size. They also have two longer tentacles that they use to catch food. These tentacles have suction cups on the end to hold on to the cuttlefish’s next meal. In between their eight tentacles, cuttlefish, like octopuses (or octopi or octopods), have a bird-like beak which they use for eating. These animals get their name from the internal shell called the cuttlebone. Although it is called this, it is not actually a bone.


Metasepia_pfefferi_1Cuttlefish, which are not actually fish but invertebrates, and are a family of animals that contains around 120 species. The red cuttlefish up above is a flamboyant cuttlefish and the pink one below it is a reef cuttlefish.



Cuttlefish are small to medium-sized in comparison to most other marine animals. Depending on the species, they grow up to 39 inches (1 m) long including the tentacles and 20 inches (52 cm) not including the tentacles. Some of these species are as small as 6 inches (15 cm). Larger adult cuttlefish can weigh around 23 pounds (10.5 kg) while some of the smaller ones only weigh 6.5 pounds (3 kg). The smallest cuttlefish lives in tide pools and is only .6 inches (15 mm) long!


Cuttlefish eat mainly crustaceans and other mollusks. Some of their normal food includes shrimp and crabs. Although these are their primary sources of nutrition, cuttlefish also eat a lot of fish.

Getting around

Most of the time, cuttlefish will use the flaps along the side of their body to move around. They will wiggle them much like the motion of waves or a roller coaster. In the event that a cuttlefish needs to move quickly, it will squirt out a jet of water much like a squid or octopus would do. During these times, the flaps mentioned earlier are used for steering and keeping stable. The cuttlebone, which is filled with a special liquid, is also used in cuttlefish locomotion. The cuttlefish can control the amount of liquid in this body part in order to control how high or low in the water the cuttlefish stays.


Cuttlefish, especially smaller ones, have many predators. One of their main predators is humans who catch them sometimes to eat them. Other predators include sharks and large fish. Sometimes cuttlefish will be cannibalistic, eating other cuttlefish in different species or even smaller individuals in the same species.


Cuttlefish have several ways of protecting themselves against these many predators. Inside the cuttlefish’s skin, there are more than 20,000,000 (twenty million) chromatophores. Chromatophores are small cells of pigment attached to super tiny muscles. When cuttlefish flex these muscles, they release pigment into the outer layer of skin, allowing them to change their color. In less than a second, they can change their color completely. They can also change the shape and texture of their body to match their surroundings. Due to this fact, cuttlefish are sometimes called the chameleons of the sea. Other protections include spraying out a dark ink that hides them from predators while they make a fast getaway using jet propulsion. Watch this video to see these protections in action.

Uses to humans

When cuttlefish die, their cuttlebones wash up on shore. Since they are made of calcium, these cuttlebones are collected by people and then sold to be given to pet birds as a calcium supplement. The brownish ink squirted out by cuttlefish is also useful to humans. For a long time, people have used this ink in art. When using this ink for painting, the resulting picture would be just different shades of brown, black and white. The name for this type of painting or picture is the cuttlefish’s scientific name:  sepia.


During the mating season, Males will “fight” for mating dens. The fights are not normally harmful and usually consist only of bright color flashing in order to prove how good they are. After the mating den has been won by a male, females that are ready to mate will come to the male. After mating, the female will lay up to 200 eggs on the roof of ceiling of the den where she cements them. Shortly after laying the eggs, the female dies.

Young and eggs

Cuttlefish eggs are larger than the eggs of most aquatic animals and the eggs of the largest species can be around .6 inches (15 mm) in diameter. After the eggs hatch, the young have at most two years to live. During this time, they grow very fast and little energy is used unless it is necessary. It is thought that cuttlefish spend up to ninety-five percent of their time resting.


Cuttlefish are thought to be one of the smartest animals in the sea. In labs, some cuttlefish have been trained to find their way through a maze.

Don’t forget to scroll to the bottom and leave your guess about what the next animal is! Also check out the coloring sheet under sources.



Photo credits:

  • Cuttlefish -public domain
  • Flamboyant cuttlefish – JennyHuang
  • Reef cuttlefish – Nhobgood
  • Mystery animal -Petter Lindgren
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