Friday, June 4, 2010
June 4, 2010 : Cuttlefish
Cuttlefish are marine animals of the order Sepiida belonging to the class Cephalopoda (which also includes squid, octopuses, and nautiluses). Despite their common name, cuttlefish are not fish but molluscs. Recent studies indicate that cuttlefish are among the most intelligent invertebrates. Additionally, it is noted that cuttlefish have one of the largest brain-to-body size ratios of all invertebrates.
The origin of the word cuttlefish can be found in the old English term cudele, itself derived in the 1400s from the Norwegian koddi (cushion, testicle) and the Middle German kudel (pouch), a literal description of the cephalopod's shape. The Greco-Roman world valued the cephalopod as a source of the unique brown pigment released from its siphon when alarmed. Hence, the word for it in Greek and Latin is sepia (later seppia in Italian).
Cuttlefish have an internal shell (the cuttlebone), large W-shaped pupils, and eight arms and two tentaclesprey. They generally range in size from 15 cm (5.9 in) to 25 cm (9.8 in), with the largest species, Sepia apama, reaching 50 cm (20 in) in mantle furnished with denticulated suckers, with which they secure their length and over 10.5 kg (23 lb) in weight.