The octopus inhabits the water along several coastal regions in temperate, subtropical and tropical areas, including alongside the western coast of Africa, the Gulf of Mexico and India. The creature is part of the mollusk family and is related to the squid. As an invertebrate, it has no skeletal structure.
Anatomical curiosities of the octopus include its possession of three hearts and blue blood. The heart that is mainly concerned with the blood circulation among the organs stops beating when the creature swims, which is why some scientists think that the octopus prefers to crawl along the ocean floor.
The tentacles of the octopus are unusual in that they hold claim to two-thirds of the creature's neurons. This enables the octopus to effectively multi-task, and it also explains how the tentacles continue to react even after separated from the rest of the body. Despite the fact that octopuses' brains are in their arms, some scientists have observed octopuses eating their own tentacles.
Perhaps more well-known is the octopus' defensive method of squirting ink at a predator. This ink is not only harmful to the pursuer, it can kill the octopus if it remains in its own ink. Some octopuses also possess poison harmful to humans.