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A cuttlefish with W-shaped pupils which may help them discern colors. All octopuses [25] and most cephalopods [26] [27] are considered to be color blind. Coleoid cephalopods (octopus, squid, cuttlefish) have a single photoreceptor type and lack the ability to determine color by comparing detected photon intensity across multiple spectral channels.
A veined octopus eating a crab.. Unlike most other molluscs, all cephalopods are active predators (with the possible exceptions of the bigfin squid and vampire squid).Their need to locate and capture their prey has likely been the driving evolutionary force behind the development of their intelligence.
Cephalopod limbs bear numerous suckers along their ventral surface as in octopus, squid and cuttlefish arms and in clusters at the ends of the tentacles (if present), as in squid and cuttlefish. [9] Each sucker is usually circular and bowl-like and has two distinct parts: an outer shallow cavity called an infundibulum and a central hollow ...
Cuttlefish ink was formerly an important dye, called sepia. To extract the sepia pigment from a cuttlefish (or squid), the ink sac is removed and dried then dissolved in a dilute alkali. The resulting solution is filtered to isolate the pigment, which is then precipitated with dilute hydrochloric acid. The isolated precipitate is the sepia pigment.
Coleoidea [1] [2] or Dibranchiata is one of the two subclasses of cephalopods containing all the various taxa popularly thought of as "soft-bodied" or "shell-less" (i.e. octopus, squid and cuttlefish).
Several types of cephalopods, most notably squid and octopuses, and potentially cuttlefish, have eyes that can distinguish the orientation of polarized light. This sensitivity is due to the orthogonal organization of neighboring photoreceptors. (Cephalopods have receptor cells called rhabdoms similar to those of other molluscs.)
An octopus (pl.: octopuses or octopodes [a]) is a soft-bodied, eight-limbed mollusc of the order Octopoda (/ ɒ k ˈ t ɒ p ə d ə /, ok-TOP-ə-də [3]).The order consists of some 300 species and is grouped within the class Cephalopoda with squids, cuttlefish, and nautiloids.
They allege that a giant octopus or a giant squid turned the boat upside down, but did not attack them afterwards, although a 12-week-old boy drowned. [ 33 ] In 2003, the crew of a yacht competing to win the round-the-world Jules Verne Trophy reported being attacked by a giant squid several hours after departing from Brittany , France.