A hippo's mouth is huge, measuring about four feet (1.2 m) from top to bottom when open. That's big enough for a six-year-old kid to fit inside! These big mouths make a lot of noise. Hippos can produce a 115-decibel roar that's as loud as a train engine. They also make softer noises such as croaks, clicks, and bellows that are heard in the air and underwater at the same time - something no other mammal can do. These are just some of the interesting facts kids will discover about these noisy giants. Spectacular photos and clear, easy-to-read text will engage emergent readers as they discover where hippos live, how they stay safe, and the different ways they communicate with each other.