When you and I take a deep breath, we pull air into our lungs. That’s because humans are mammals. But fish aren’t mammals. They usually don’t breathe air. They usually don’t have lungs. That’s what I ...

Watching a fish glide through water gives the impression that it moves in a world foreign to ours. But if we need air to live, how do these animals manage to breathe beneath the surface, where our ...

All living organisms have to breathe, exchanging oxygen and carbon dioxide with the environment. How do fish do it without lungs? This viewer question comes from Zambia. Actors Who Permanently Damaged ...