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Curiosity Challenge: How Does an Octopus Breathe in Water?

Alexis, 6
Alexis, 6

Hi Alexis, awesome question. My name is Brian Helmuth, and I’m a marine biologist at Northeastern University’s Marine Science Center. I study the oceans to see how they are changing, and to find ways of protecting them. I don’t know about you, but my favorite character in Finding Dory is, all 8 arms down, Hank the octopus, who is able to move around outside of his tank and hide just about anywhere. There are real octopus who have escaped from their aquariums to eat fish in another tank next door, and then returned home after putting the lid back on the tank to hide what they have done!

There are real octopus who have escaped from their aquariums to eat fish in another tank next door, and then… Click To Tweet
Disney Gallery
Disney Gallery

But back to your question, like humans, octopus need to breathe oxygen to survive. But, unlike people, an octopus can be in air for only a few minutes. They much prefer to be in the water where they can breathe with their gills. In the picture below you can see an opening on the side of a Giant Pacific Octopus (did you know that they can get to be as long as a school bus?!).

Side view of the octopus gills
Side view of the octopus gills

This is where her gills are. By pumping water through this opening and over her gills she can get oxygen from the water, just as you get oxygen from air when you breathe through your mouth and nose. Like our lungs, gills in animals like fish and octopus are made of very thin layers of tissue that allow oxygen to enter in to the blood, where it is then pumped through your body by your heart. The difference is that our lungs work in air, but you would drown if they filled with water. The difference is that our lungs work in air, but you would drown if they filled with water. Click To Tweet The opposite happens in octopus- they are really good at taking oxygen out of water, but the gills are too flimsy to work in air. Oh, and Dory is right- octopus really do have three hearts- two move the blood from the gills and a third moves it to the octopus other organs. This third heart actually stops beating when the octopus swims, which is part of the reason why they would much rather crawl!


Brian Helmuth is a marine biologist at Northeastern University’s Marine Science Center

One Comment on “Curiosity Challenge: How Does an Octopus Breathe in Water?

  1. So in Finding Dory Hank would not be able to out of water that long only about 20 minutes at a time?

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