Most people associate cuttlefish with domesticated budgies (the bird, not the male swimsuit). This is because budgies are given cuttlebone, a long ovulated white structure, to sharpen their beaks. This beautiful cuttlebone is an important feature of the cuttlefish; it controls their buoyancy while swimming in the ocean at various depths.
Cuttlefish can be found across the globe. They belong to a group of animals termed cephalopods, which also includes the octopus, squid, chambered nautilus and argonauts. Scientifically, cuttlefish belong to the Class Cephalopoda in the Phylum Mollusca. This means cuttlefish are invertebrates and have no backbone.
Cephalopods are considered amongst scientists to be the most intelligent out of all invertebrates; they learn quickly, are able to solve problems, communicate via complex visual communication and can quickly adapt to their local environment. Like chameleons on land, cuttlefish are experts at adapting to the colour and patterns of the environment around them.
Cuttlefish, as well as the octopus, contain special organs in their skin termed chromatophores which are little elastic bags filled with colour pigment. By expanding and contracting, chromatophores display a particular colour. They can be turned on and off which allows the cuttlefish to create a particular set of colours and patterns with its skin. Additionally, skin flaps, termed papillae, can be pushed or shaped to mimic their surroundings, for example, seaweed or coral. These colour and pattern changes are used for: mating and courting rituals, mate-guarding and camouflage to hide from predators.
Here are some more fascinating facts about cuttlefish:
Fact 1: Cuttlefish have very well developed eyes and acute vision. They are colour blind but respond to differences in light intensity rather than differences in wave length (which vertebrates, like humans, use to determine colour).
Fact 2: Cuttlefish are carnivores, that is, they eat meat. They are active nighttime predators feeding on fish, crustaceans, shellfish and worms.
Fact 3: During mating, the male passes packets of sperm to the female using its modified arm termed the hectocotylus. The females can immediately fertilise their eggs or are able to store the sperm in special receptacles inside their body for periods of time until they want to fertilise their eggs.
Fact 4: Females attach the fertilised eggs to the seafloor either on or under hard surfaces such as rocks. Young cuttlefish develop with no parental assistance and many hatchings are carried around in surface ocean currents over long distances.
Fact 5: Cuttlefish have 8 arms and 2 feeding tentacles. All arms have suckers along the length of the arm except for the feeding tentacles which have suckers only on the tip, termed clubs. The feeding tentacles can be pulled back into the mouth.
Fact 6: A cuttlefish’s mouth contains a hard beak, similar to a parrot’s beak. The beak is used to kill and paralyse the prey by injecting a poisonous saliva. The beak also breaks the prey into pieces and then it is further broken down with a row of very small sharp teeth.
Fact 7: When scared or irritated, cuttlefish squirt ink into the water column which can be shaped to be the same size as its body. This ink sac sits inside the body near the anus. Cuttlefish are also able to bury themselves under sand, with only the eyes remaining visible, when they want to hide.
Fact 8: Cuttlefish use their funnel and fins to swim. The fins extend out from its mantle (the back part of its body) enabling rapid or slow propulsion.
Many larger marine animals such as seals, whales and large fish eat cuttlefish, however, they are rarely caught in fisher nets. Perhaps this is indicative of their intelligence and being able to problem solve in difficult situations?