NAME:  OCTOPUS

CLASS:  CEPHALOPODA

SUBCLASS:  COLEOIDEA

ORDER:  OCTOPODA

LOCATION:  DIFFERENT SPECIES ARE FOUND IN ALL THE OCEANS OF THE WORLD.  MANY SPECIES PREFER LIFE IN THE WARM SHALLOWS ALONG CORAL REEFS, WHILE OTHERS (GIANT PACIFIC) ARE FOUND AT DEPTHS OF UP TO 1500 FEET.

RECOGNITION FEATURES:  SOME SPECIES AS SMALL AS A TENNIS BALL, AND OTHERS UP TO 600 POUNDS (GIANT PACIFIC OCTOPUS). OCTOPUSES ARE KNOWN FOR THEIR STRANGE APPEARANCE AND EIGHT ARMS ATTACHED TO A HEAD/BODY.  THESE ANIMALS COME IN A VARIETY OF COLORS, FROM AN ALMOST NEON BLUE, TO ORANGES, AND REDS (MORE TYPICAL).

DETAILS:

Octopuses are certainly one of the more interesting and bizarre animals found in the seas.  The majority of the species of octopuses are invertebrates, with the only hard part of their anatomy being a beak used to kill and eat their prey.  An octopus' anatomy consists primarily of a head and eight arms.  The head has two eyes, one on each side of its head, which provide the animal with extremely good eyesight.  Octopuses do not have any ears, and are deaf.  The head is actually the entire body, and houses all the vital organs, including the octopus' three hearts, gills, and mouth.  The eight arms normally contain a series of suction cups which allow the animal to grasp and break open shellfish, and the bones of larger fish. Since octopuses normally do not have an internal skeleton (although there are a few species that do) they are well-suited to slip into narrow crevices to escape predators, and sometimes live in empty shells of mollusks. 

The reproductive life of octopuses is quite the tragic tale, and is the reason that these animals have such a short life span—typically just a few years.  After mating, males die within a few months, and females die after their eggs hatch, as they seem to have a one-track mind and fail to eat during the pregnancy, devoting all their attention to the eggs. 

Octopuses are considered extremely intelligent creatures, and seem to have developed long-term, as well as short-term memories.  Octopuses that are kept in captivity are known to escape, and if there are other fish tanks nearby, have been observed escaping one tank, moving to another—sometimes living out of the water for fairly long periods—and entering another tank full of fish.  Anecdotal evidence also exits of octopuses climbing aboard fishing vessels and entering the hold with the catch.

The defense system of the octopus is extremely well-developed and varied.  In addition to being able to crawl into narrow spaces, octopuses also can eject an ink cloud to distract would-be attackers.  Their skin possesses certain types of cells which are able to change color, providing the animal with a type of camouflage. Finally, like other animals, such as some types of lizards and worms, octopuses can detach an arm and escape.  

Octopuses means of locomotion are varied.  They are able to use their eight arms to crawl about on the sea floor, while at the same time, using their highly developed sense of touch to search for food.  These animals are also able to propel themselves through the water by shooting a jet of water from a mantle and siphon.  Finally, octopuses have been observed 'walking' on two of their arms, while using the others for camouflage.  The two species who are able to 'walk' like this are the octopus marginatus and the octopus aculeatus.