The octopuses are among the most intelligent and behaviourally of all invertebrates.
Octopuses didn't change since 500 millions of years. Strange animals with arms directly attached to the head they are called: Cephalopodes. At the beginning the Octopus was a Mollusk with shell. It is probably to escape from his prey that it slowly abandoned the heavy shell.
All cephalopods are soft bodied, with arms around a central mouth, highly developed, image forming eyes; and a tube-shaped organ called a funnel, or a siphon near the head.
Cephalopods have evolved a remarkable variety of modes to get from one place to another. Some swim using all their arms or web, some wave small fins along their body, and others can actually walk from place to place !
Octopus actually had shells similar to clams and snails,...
They have three hearts, nine brains and blue blood. Two hearts pump blood to the gills, while a third circulates it to the rest of the body. The nervous system includes a central brain and a large ganglion at the base of each arm which controls movement.
Octopuses are sea animals famous for their round bodies, bulging eyes, and eight long arms. They live in all the world's ocean but are especially abundant in warm, tropical waters.
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