Octopus Respiration
Octopuses have a beak-like mouth that is located on the mantel cavity at the back of the bulbous head of the octopus which is surrounded by eight legs. The mouth is the mantle cavity's entryway that has gills inside it. This allows the octopus to breathe. The water enters the octopus' mouth and is passed through the gills to enter back into the water. As the water is pushed over the surface of the gills, oxygen is picked up by the blood in the capillaries of the gills. The blood in the octopus travels in the opposite direction in the gills than the direction that the water is traveling. This allows the octopus to gain maximum oxygen exchange per breathe.