Mammals Like Us! Click on a picture to see a bigger one. Whales are mammals because . . . They breathe air using their lungs. Did you notice the blowhole on top of the head? This is where air comes in and goes out. A whale can only breathe when its blowhole is above the surface. Could you breathe under water? (Fish, unlike mammals, use gills to take in air from the water.) Whales don't need to breathe as often as we do because they take in a huge amount of air. When they exhale the warm, moist air, you see the spout shoot straight up! Next   Facebook Pinterest Twitter © 1997 – 2019 Journey North. All rights reserved.