Cuttlefish not only change their colour to match their surroundings. They have what appears to be a language of thousands of colours and gestures. Researchers studying cuttlefish in tanks find that they swim up to the side of the tank and make specific colour displays when certain researchers enter the room. This seems to indicate recognition and memory, the desire to communicate. Perhaps they are saying, "Ohayo!" or "Good Morning!" or "You again. Did your mother dress you? You are such a loser." No one knows. But it seems they are saying something.

Cuttlefish, octupi, and squid are common in Mediterranean and Asian diets. Dried cuttlefish are packaged as cheap snacks...

I have learned two very odd but interesting things about cuttlefish courtesy of the Discovery Channel.

1. The cuttlefish does not see as we humans do or even our friends canis familiaris. No, the cuttlefish sees bent light. "Now," you say, "what the hell use would seeing bent light be?" Not much, if you are you or me, but if your food consists of transparent shrimp, seeing bent light just might help you find dinner.
2. The other interesting thing about cuttlefish is their manner of catching/attacking said shrimp. The cuttlefish moves all but two of its tentacles up in front of itself, twisted in a strange pattern, such that it really does look from the front like a big mass of tangled seaweed. Now, since it's a cephalopod, it has a siphon propulsion system. This allows it to move forward slowly and silently, still looking like a tangled mass of seaweed. At this point it launches out its last two tentacles from within the others, and grabs the little shrimp with them, pulling it back to its beak with which it crushes and consumes it. Cool, huh?

for sensei, who is precious to me

The cuttlefish is the most interesting and beautiful animal on earth.

Kingdom Animalia
Phylum Mollusca
Class Cephalopoda
Subclass Coleoidea
Superorder Decapodiformes
Order Sepiida

The next time you buy a cuttlebone to fix to the side of your Budgie's cage, give it a good close look.

The cuttlefish is a small cephalopod similar to squid that inhabits the English Channel, the Mediterranean Sea, and the oceans along the west coast of Africa. Its mantle (body without arms) typically reaches a length of 20 to 30 centimeters. An oversized football.

Like other cephalopods, the cuttlefish keeps most of its organs in the squishy sack above the eyes. The mantle is fringed on each side with a short, thin fin that ripples like a flag. It has eight arms and two long tentacles, which retract completely into the body and extend as though spring-loaded to capture prey. It has a beak and shoots ink — in this case the useful pigment sepia — like an octopus or a squid. Quick movements are accomplished with jet power: expulsion of water through a siphon. It eats small crustaceans and fish and other cuttlefish.

The cuttlebone is the most well-known part of the cuttlefish. It's an internal shell made of calcium carbonate and acts like a swim bladder. The cuttlefish rises and sinks by injecting or removing gas from the bone. The cuttlebone prevents the creature from venturing into deep waters by imploding under pressure. It's rich in calcium and salt and makes a good supplement for a captive bird.

The cuttlefish has some of the most sophisticated eyes on the planet. They're similar to ours but the pupil runs the horizontal length of the eye and looks like a smooth W-curved ribbon — like a goat's eye only weirder. Stare down a cuttlefish without getting creeped out.

The cuttlefish has a short lifespan: a year or two. Mating cycles occur year-round, spiking in March and June. Cuttlefish have the male and female sexes we're used to: males deposit sperm with a hectocotylized arm, an arm specialized for mating. Eggs are large, about 6-9mm, and are stored in the female's oviduct until distribution in clumps on the sea floor. Typically the eggs are tinted with sepia to blend with the sand. After roughly two months the young hatch with a supply of yolk that serves them until they are able to secure prey. Cuttlefish hatchlings are much more highly developed than squid or octopi, so they're able to start taking down small crustaceans almost as soon as they hatch.

Now for the cool stuff.

The cuttlefish's blood is greenish blue, like an alien. The color results from the pigment hemocyanin used to carry oxygen. In red-blooded animals oxygen is carried by hemoglobin.

The cuttlefish is called the chameleon of the sea; this is an insult to the cuttlefish. The cuttlefish's color changes make the chameleon look like a failure. No gradual overshading over the course of several minutes here: these things do it instantly. When they're angry it looks like fireworks. Color changes are accomplished by small structures in the skin called chromatophores, leucophores and iridophores, tiny bags of ink that contract and expand to create color like pixels on a screen. Skin texture can be changed as well. They come in colors red, yellow, brown, and black. A layer of chromatophores is above a layer of iridophores; the iridophores are above a layer of leucophores. Each square millimeter of skin can contain 200 bags of pigment. The little bags are controlled by 6 to 20 muscle cells that squish and pull apart. Colors are used to hide from predators and to communicate with other cuttlefish. Basic color is a mottled black or brown.

Cuttlefish are kept as pets primarily in the UK. They're said to be very much like cats — they rest, pounce, and beg for food even when they're fat. Cuttlefish imported to the US as pets are typically the poor-traveling Sepia bandensis from Bali that arrive four inches long and have weeks to live.

Cuttlefish are demanding creatures, even for bare-bones maintenance. They require levels of salt water in very specific proportion to their body size and cannot handle abrupt changes in light. Their tanks need to be cleaned every time they ink. They don't coexist with other animals because they eat everything, including each other.

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XWiz adds that the cuttlebone is an essential source of calcium for the Giant African Land Snail, another strange animal that's sometimes kept in captivity. This one's illegal in the US, though.

Gritchka adds that cuttlebones are a common find on the beaches of Victoria; the North Atlantic distribution outlined above refers to the species S. Officinalis — the common cuttlefish.

Sources

Divernet
http://www.divernet.com/biolog/cuttle899.htm

Wikipedia
http://en.wikipedia.org/wiki/Cuttlefish

Marinebio dot org
http://www.marinebio.org/species.asp?id=540

King, Alison Jane. "The Common Cuttlefish."
www.nhm.ac.uk/hosted_sites/tcp/Soffic.htm

Abyss Scuba Diving
www.abyss.com.au/cuttle.html

Cut"tle (kut"t'l), Cut"tle*fish` (-f?sh`), n. [OE. codule, AS. cudele; akin to G. kuttelfish; cf. G. ktel, D. keutel, dirt from the guts, G. kuttel bowels, entrails. AS. cwip womb, Gith. qipus belly, womb.]

1. Zool.

A cephalopod of the genus Sepia, having an internal shell, large eyes, and ten arms furnished with denticulated suckers, by means of which it secures its prey. The name is sometimes applied to dibranchiate cephalopods generally.

It has an ink bag, opening into the siphon, from which, when pursued, it throws out a dark liquid that clouds the water, enabling it to escape observation.

2.

A foul-mouthed fellow.

"An you play the saucy cuttle me." Shak.

 

© Webster 1913.