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The Clever Cuttlefish
Master of Camouflage even though Colour-Blind
The cuttlefish is a fascinating creature. This intelligent mollusc has almost incredible powers of mimicry. It can control the colour, patterning and texture of its skin to perfectly match its surroundings. And not just from above, the camouflage works from whichever angle it is observed. From birth, cuttlefish can display at least 13 type of body pattern, made up from over 30 different components. And all this whilst being colour-blind.
Cuttlefish Courtship
In addition to avoiding predators, pattern control is also used in courtship by male cuttlefish. This impresses females and warns off competitors. After mating the male will often defend the female while she lays clumps of eggs. These hatch in two to three months to reveal miniature cuttlefish. Females only breed once and die soon after laying.
Jet Propulsion
With its flattened body skirted each side with fins, the cuttlefish moves with a pretty rippling motion. Like the closely related octopus, it can also escape by powerful jet propulsion whilst simultaneously ejecting a cloud of black ink to distract its foe. This ink is called sepia and was once used by artists.
10 Arms and 3 Hearts
The cuttlefish's mouth is surrounded by eight arms. It also has two long extendable tentacles and is thus classified as a decapod (10 feet). Carnivorous, cuttlefish catch fast-moving prey like crustaceans and fish with their long tentacles. Two of their three hearts send blood to the gills, the other pumps blood around the body.
Bouyancy control in their bones
The Cuttlefish bone is filled with small chambers. They fill or release air from these chambers to control their buoyancy.
Of course, being an invertebrate the cuttlefish bone is not really a bone, more of an internal shell.
Clever Cuttlefish
A recent study showed that like some vertebrates, cuttlefish can exert self-control for over two minutes at a time.
Cuttlefish will wait for a better but delayed reward of their favourite food. In the tests, all cuttlefish liked live grass shrimps best, pieces of raw king prawn came next and Asian shore crab was the least preferred.
The cleverest cuttlefish, that learnt the most quickly, could wait for longer. Chimpanzees, dogs and grey parrots have been shown to employ strategies such as looking away, closing their eyes or distracting themselves with other objects while waiting for a better reward. Interestingly, cuttlefish were observed turning their body away from the immediately available prey item as well, as if to distract themselves when they needed to delay immediate gratification.
Animalia (Kingdom) > Mollusca (Phylum) > Cephalopoda (Class) > Coleoidea (Subclass) > Decapodiformes (Superorder) > Sepiida (Order)
Further Reading
10 Fascinating facts about the clever cuttlefish, SCUBA Travel
Alexandra K. Schnel et al Cuttlefish exert self-control in a delay of gratification task, The Royal Society, March 2021
"Chameleon of the sea" reveals its secrets, Harvard School of Engineering and Applied Sciences
Great British Marine Animals, by Paul Naylor
Leila F. Deravi, Andrew P. Magyar, et al The structure-function relationships of a natural nanoscale photonic device in cuttlefish chromatophores J R Soc Interface 2014 11: 20130942
NAOHIKO WATANUKI et al, Role of vision in behavior, visual field, and visual acuity of cuttlefish Sepia esculenta
Lydia M. Mäthger et al Color blindness and contrast perception in cuttlefish (Sepia officinalis) determined by a visual sensorimotor assay 2006
by Jill Studholme