As you might know, everything on the inside of you is very important. Your bones keep you standing up so that you're not just a puddle of skin on the ground. Your stomach helps you eat food and be healthy. And so many other things that keep you alive. Same goes for animals. For every animal, there are a few parts on the inside that are extra important. For hippos, their stomach is unique and useful. After they eat food, the food travels to their stomach. Which is divided into 4 sections. Like humans, a hippo doesn't have an appendix. The appendix really has no purpose for humans though. A hippos skin is about 2 inches thick, which helps them to not get too hot or cold. It's a gray color. Their skin must be kept moist and not too dry because it might crack. Hippos can be very sensitive to heat from the sun.