About

How do fish breathe underwater? Find out in this BrainPOP movie, as Tim and Moby give you the inside scoop on gills. You’ll learn what gills have in common with human lungs, and why not all aquatic animals have them. You’ll also discover that fish don’t actually breathe water, and learn what it is they’re really breathing. Plus, Tim will introduce you to diffusion, the physical property that makes gills work. Finally, you’ll find out why breathing underwater isn’t very efficient, and how something called “countercurrent exchange” makes extracting oxygen from water a little easier. As far as we humans are concerned, we’re just going to have to stick to holding our breath!