The cuttlefish (Sepiida), is a type of marine cephalopod, related to octopus and squid and characterized by a thick calcified internal shell called cuttlefish. The approximately 100 species of cuttlefish range from 2,5 to 90 cm and have somewhat flattened bodies bordered by a pair of narrow fins.

All species have eight arms and two longer tentacles that are used to capture prey and can be removed in two bags. The suction discs are located on the arms and on the expanded pads at the tips of the tentacles.

The cuttlefish is an invertebrate mollusk.

The cuttlefish is an invertebrate mollusk.


Like its close relatives, the cuttlefish produces ink internally and they also have a neurotoxin that can be used on prey and rivals alike and is even lethal to the blue-ringed octopus.

Cuttlefish have a variety of unique and intriguing characteristics - cuttlefish eyes, for example, are particularly notable for their 'w' shaped pupil. The unique pupil formation provides a very well developed vision that focuses on contrast rather than color, which works especially well in its dark underwater environment.

We can appreciate the W-shaped eye of the cuttlefish

We can appreciate the W-shaped eye of the cuttlefish

The eyes have two concentrated sensor points. One sensor is at the front to look forward and the other is located at the rear, allowing you to look behind.

Another notable feature of the cuttlefish is its skin, it is a master of camouflage and has unique skin cells that can change pigment to create a wide range of colors, including metallic green, blue and yellow. With this ability the cuttlefish can even influence the color of the light reflected off its skin and even the polarization of the light that can be used to point at others. It changes the color of its body in different hues for different purposes such as contact, protection, attraction of its partner and the capture of its prey.

La mammal blood it is red because it contains a protein called hemoglobin that contains iron, on the other hand cuttlefish blood is green because instead of containing hemoglobin it contains hemocyanin that contains copper. However, color is not the only difference that blood has, since due to the type of blood it has, it must pump blood much faster than a mammal and as a result of this the cuttlefish has 3 hearts, two of which are They are used to pump blood to the cuttlefish's gill pair and the third to pump blood around the rest of the body.

This animal doesn't swim, it just floats.


These cephalopods are found in all the world's oceans, from warm tropical waters to icy polar waters. They are in the intertidal zone swept by cold waves. Cuttlefish, however, are usually found in temperate and tropical waters. They prefer shallow coastal waters, but are also found in the open ocean. During the winter, cuttlefish flock in numbers on the reefs near shore to mate and spawn.

Some species of cuttlefish swim in schools, as do other fish, while others are more solitary and guard their own territory.


Spanning a large portion of the world's oceans from western Europe to the coast of Australia, these interesting mollusks prefer warm-water tropical climates and are primarily found in warm shallow waters, but are occasionally known to inhabit depths of up to 600 meters. . The only place where cuttlefish are not caught is in the waters of the Americas, currently it is believed that the reason for this is because the water is too cold.

The giant cuttlefish is only found in the waters of southern Australia. They inhabit areas of reefs and seagrasses from Point Cloates in Western Australia, along the southern coast and into New South Wales.


The diet of the cuttlefish is preferably crabs and fish. Being a master hunter, he uses his cloaking ability to get close to his prey before launching 2 long tentacles from inside his beak into the center of his arms and proceeds to drag prey and administer neurotoxins through his beak.


Its predators include dolphins, sharks, fish, seals and other cuttlefish. Their life expectancy is one to two years.


Mating begins in winter, when large numbers of these mollusks gather on shallow reefs close to shore. Rival males become aggressive towards each other, widening the webbing membrane between their tentacles and turning bright colors. Then, they surround each other, copying each other's movements.

The larger and more colorful male wins the match and neither of them is harmed. Sometimes, however, some males become more violent and a male tries to bite his rival. To attract females, males spread their tentacles and use all of their colors in an effort to impress the females.

Mating and spawning

They mate head to head and when in position, they attach their tentacles. The male places a sealed sperm packet in the bag just below the female's mouth.

The female then retreats to the burrow, which is usually a deep crevice or fissure in the rocks, or even a small cave to spawn. There she removes each ovum from its mantle individually and passes it over the sperm. Lays up to 200 eggs.

The male often becomes rather aggressive when taking care of a female with whom he has mated, until she spawns. He blocks the entrance to the den while the female lays her eggs to prevent other males from washing his sperm with their siphon and then inserting their own sperm packet.


The life cycle begins with the newly fertilized eggs hanging from the rock in dense clumps. They are white and covered in a sticky, jelly-like material. Inside the eggs, the cuttlefish soon develop and after 4 months, they hatch.

Cuttlefish are 25 millimeters long and have all the features of their parents. Predation rates are high and very few of the newly hatched cuttlefish survive beyond their first hours. Those that survive grow rapidly and live in deeper waters.

The new adult cuttlefish are ready to spawn between 18 and 24 months of age. After spawning, the females soon become lethargic and their bodies rapidly deteriorate.

Overfishing and pollution pose a serious threat to cuttlefish populations, as they have a very short life span and only spawn once in their lives.

State of conservation

This animal is listed as Least Concern (LC).


Cuttlefish are sometimes referred to as sea chameleons because of their remarkable ability to rapidly alter their skin color at will. Their skin features a rapidly changing pattern for communication with other cuttlefish and to camouflage them from predators. This color-changing function is produced by clusters of red, yellow, brown, and black pigmented chromatophores on a layer of reflective iridophores and leukophores, with up to 200 of these specialized pigment cells per square millimeter. Pigmented chromatophores have a pigment sac and a large membrane that folds when retracting. There are 6 to 20 small muscle cells on the sides that can contract to crush the elastic sac into a disk against the skin. All of these cells can be used in combinations.

Cuttlefish eyes are among the most developed in the animal kingdom. Scientists have speculated that the eyes of the cuttlefish are fully developed before they are born and begin to observe their surroundings while they are still in the egg.

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