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Dietīlue-ringed-octopuses hunt during the day. Adults are usually less than 5 cm (1.97 in) long with arms to 7 cm (2.8 in) when extended. lunulata is about the size of a grape seed at birth and that of a golf ball at maturity. The body is often covered with papillae that give it a rough appearance. At such a time the, faint blue rings change to a brilliant iridescent blue that often seem to glow. Each ring has a dark blurred edge, containing some of the chromatophores that cause color changes when the animal is stressed. The center of each ring is usually a dark brown color. Up to 25 faint blue rings as large as 8 mm (0.3 in) in diameter cover the dorsal surface, mantle, and extend out over the arms. Their body background color at rest is usually tan to dark yellow. Greater blue-ringed octopuses have a soft sac-like body and eight sucker-covered arms. These octopus are bottom dwellers inhabiting sandy and silty areas in shallow coral reefs, tidepools, and clumps of algae at depths of 0-20 m (0-66 ft).They hide in rock crevices, inside empty seashells, and in discarded bottles and cans.
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Northern Australia to Japan including Papua New Guinea, Solomon Islands, and Indonesia as far west as Sri Lanka. Roy Caldwell, University of California Berkeley, for his review of this information. Information included in the Ocean Learning Center for use as a reference. SPECIES IN DETAIL Greater Blue-ringed OctopusĬLIMATE CHANGE: Not Applicable At the Aquarium