Octopuses are soft-bodied invertebrates with eight limbs, each covered on the underside with sticky suction cups that they use for grasping. A sharp, parrot-like beak is located on the underside of the animal where the limbs converge.
An octopus’s body can assume many different shapes, allowing the octopus to camouflage itself, or fit within very narrow passageways. A structure called a siphon is used to both help the octopus breathe, and propel it forward by shooting jets of water.
The largest octopus species is the giant Pacific octopus, which can grow to have an arm span of nearly 15 feet, and weigh over 150 pounds in rare cases. Some claims indicate it may grow much larger, to 30 feet across. The smallest octopus species grows only about one inch long, and weighs less than one gram.
All octopuses possess venom, but few are dangerous to humans. The blue-ringed octopus, found in the Indo-Pacific Ocean, is one of the most toxic animals alive, and its venomous bite is very dangerous to humans.