Common Squid     Loligo opalescens



Looking like a fat ball point pens, Common Squid are occasionally seen around docks.  They usually come up to the dock lights at night in the fall and winter. Squid are closely related to octopus. Both are members of the Cephalopods or "Head-footed" animals.  They are both related to chitons, clams and snails, all of whom are called Mollusks.


Squid are fascinating animals that, like the octopus, have higher intelligence than other invertebrates and even a crude language.  Squid communicate with each other using visual signals based on flashing body color patterns. The patterns are made by the contraction or expansion of pigment-containing cells in the skin which are connected by nerves to the brain. The pigmented cells can be seen as dark brown dots on the squid in the photograph.  Sometimes communication can be seen between squid in schools that are drawn to dock lights. Like the octopus, squid can also use the pigmented cells to match the background of the bottom - particularly when they come into shallow water to spawn.


The large eyes allow the squid to operate in deep water during the day and track their prey when they rise from the depths at night to feed. Squid use their parrot-like beaks set between the arms to hold and tear apart prey.  In addition to the eight arms, squid have two tentacles that are longer and used to capture the small fish, shrimp or other small swimming animals upon which they feed. The tentacles have another function. During mating the male places his sperm, using a specialized part of the tentacle tip, in the mantle of the female. After several days she will fertilize her eggs, lay them on hard substrate, and then die. The second photograph is of a mass of squid eggs laid on a rock in shallow water (Photograph provided by Peggy Yates of Hartstene Island).


Squid swim slowly forward or backwards using the flap-like fins on the rear of their body.  In emergencies, when escape speed is important, they forcefully expel water from their mantle through a siphon under their head which acts as a jet propelling them backward.