1.They are very smart creatures." Octopuses, some 300 species of which inhabit tropical waters around the world, can change colors, squirt out poison, and exert a force greater than their own body weight. ... Mather has been studying octopuses for 35 years in an effort to gain insight into the evolution of intelligence.The giant Pacific octopus has three hearts, nine brains and blue blood, making reality stranger than fiction. A central brain controls the nervous system. In addition, there is a small brain in each of their eight arms — a cluster of nerve cells that biologists say controls movement. ... Two hearts pump blood to the gills.br br 2.The numbray or spottail sleeper ray is a species of electric ray in the family Narkidae. It may be found in shallow muddy estuaries or offshore depths. It is a weak swimmer that lies on the bottom, commonly buried.