One of our popular display specimens are common cuttlefish, Sepia officinalis, a member of the class Cephalopoda, which also includes octopuses and squids. We acquired a dozen specimens from the University of Texas at Galveston, where researchers culture cuttlefish for biomedical, physiological, pharmaceutical, and behavioral studies. Research using the common cuttlefish has also been done at Scripps Institution of Oceanography. Our ultimate goal for this display is to establish a cuttlefish propagation program.
Life as a CuttlefishThe common cuttlefish lives in coastal waters throughout the Mediterranean Sea and the eastern Atlantic from England to North Africa. They can tolerate water temperatures from 60° to 82° F, but prefer temperatures around 70° F. They are found in habitats ranging from sandy bottoms to algae beds to coral reefs. The common cuttlefish typically lives one to three years depending on factors such as water temperature and predation. They can grow to a length of 16 inches, but are more commonly about 10 inches long. Cuttlefish have eight arms and two tentacles which can shoot out quickly to capture prey. When approaching prey, the cuttlefish quite often assumes a stance in which it holds two of its arms up above its head.
Once the prey is grasped, the arms are used to direct it toward the mouth. The cuttlefish uses a parrotlike beak and a radula (scraping tongue) to tear prey apart. uttlefish eat small molluscs, crabs, shrimps, small fishes, and other cuttlefishes. Their main predators are sharks, larger fishes, and other cuttlefish. Due to their territorial behavior and tendency to consume each other, we try to keep a relatively large number of cuttlefish in our tank. This helps spread the competition out. We also feed our specimens daily, since a well-fed cuttlefish is a mellow cuttlefish.
Disguises and DefenseThe common cuttlefish can produce a fantastic repertoire of colors, patterns, and skin textures. They can rapidly change color, using mostly dark browns, light browns, and whites. They often display a strobelike pattern that actually moves throughout the length of the body. For social signaling, such as in courtship and while schooling, and for defense, cuttlefish can produce color patterns that contrast with their background. They can also camouflage themselves by matching and blending in with the hue, intensity, and even the texture of their habitat. When disturbed, cuttlefish can expel a dark brown ink. This is done to either confuse an intruder or prevent it from seeing the direction of escape. With a burst of water through its siphon, the cuttlefish can jet-propel itself to safety.
Spotting a CuttlefishCommon cuttlefish spend much time partially buried in bottom sand. Each morning we find patches of uncovered tank bottom where they have spent the night. They usually swim about only when they are hungry or investigating something in their territory. This may be a tank mate, a new toy, or an aquarium visitor on the other side of the glass. Shining objects like watches and rings usually draw the most attention. Cuttlefish are visually oriented and very curious. We provide them with toys because they need to be stimulated and entertained. It also helps to cut down on mutual agression. We often see them hovering close to the front glass of the tank, observing the people walking by. One might wonder who is really on display.
-Bob Burhans, Aquarium Curator