I think Cuttlefish are among one of the most unusual species found in our ocean. We luckily see them at most of our dives sites here in Tenerife, its always interesting to watch them change colour and pattern so rapidly depending on their mood and to become camouflaged to match their background. I have not yet witnessed them when they feel threatened, but they are known to release ink to try and confuse their predator.
They belong to the same family as squid and Octupus, in turn
they are among the most intelligent invertebrates and have one of the largest brain-to-body size ratios of all invertebrates.
They have a unique internal shell, known as the cuttlebone, which is gas filled and the cuttlefish use this to assist with their buoyancy control. Today, cuttlebones are commonly used as calcium-rich dietary supplements for caged birds, chinchillas, hermit crabs, reptiles and snails.
Cuttlefish eat small molluscs, crabs, shrimp, fish, octopodes, worms, and other cuttlefish. They use their camouflage to hunt and sneak up on their prey. They swim at the bottom, where shrimp and crabs are found and shoot out a jet of water to uncover the prey buried in the sand. Then when the prey tries to get away, the cuttlefish open their arms and shoot out two long feeding tentacles to grab them. On the end of each, a pad covered in suckers grabs and pulls prey toward its beak, where it gets paralyzed by venom and then eaten.
Cuttlefish are also known to rapidly change their colors to achieve an effect of hypnosis to stun their prey before catching and consumption.
Their predators include dolphins, sharks, fish, seals, seabirds, and other cuttlefish. The average life expectancy of a cuttlefish is about one to two years.
Male cuttlefish challenge one another for dominance and the best den during mating season. During this challenge, no direct contact is usually made. The animals threaten each other until one of them backs down and swims away. Eventually, the larger male cuttlefish mate with the females by grabbing them with their tentacles, turning the female so that the two animals are face-to-face, then using a specialized tentacle to insert sperm sacs into an opening near the female’s mouth. The male then guards the female until she lays the eggs a few hours later.
The most successful methods to acquire a mate is camouflage; smaller cuttlefish will use their camouflage abilities to disguise themselves as a female cuttlefish. Changing their body color, concealing their extra arms (males have four pairs, females only have three), and even pretending to be holding an egg sack, disguised males are able to swim past the larger guard male and mate with the female.
As I mentioned, they are very intelligent!