Squids do not have lungs. Lungs do not really work under water. They have gills. Squid bodies are covered with a mantle, which is sort of like a tube sock.

How does a squid breathe?

Gills. Squid use oxygen from seawater for respiration. The seawater enters the mantle through the opening near the head, and passes over the gills. Oxygen diffuses from the water into the blood, and is transported to the gill (or branchial) hearts by a network of many blood vessels.

Why do squid have 3 hearts?

Octopuses have three hearts: one pumps blood around the body; the other two pump blood to the gills. … The three hearts help to compensate for this by pumping blood at higher pressure around the body to supply the octopuses’ active lifestyle.