The octopus group makes up around a third of the world’s cephalopod population, with around 300 species found in waters around the world. The octopus can be found in all the world’s oceans, with the octopus ranging in size from a few centimeters to a number of feet depending on the species. The octopus often has a sharp beak, and always has eight arms. Most species of octopus generally have arms with circular sucker pads on.