While hippopotamuses and rhinoceroses may look similar, they are very different creatures. Hippos spend much of their time in slow-moving rivers. Rhinos, depending on their species, live in grasslands, floodplains, swamps or rain forests.

The word hippopotamus comes from a Greek word that means water or river horse. However, hippos may be more closely related to pigs, whales and dolphins than horses. Because they spend much of their time in the water, their eyes, ears and mouths are on the top of their heads. They also have a kind of built-in goggle that covers their eyes for protection and allows them to see underwater. Hippos can hold their breath for 5 minutes and can even sleep underwater because of a reflex that allows them to surface for a breath without waking.

There are five different species of rhino. Black and white rhinos live in Africa, Sumatran and Javan rhinos make their homes in Indonesia and Malaysia, and greater one-horned rhinos live in India and Nepal. All rhinos have one or two horns, poor sight, thick skin and excellent hearing. They also enjoy rolling in the mud. Their think skin serves as protection but can also be easily scarred. Mud and dust help protect them from insect bites and sunburn. Due to their poor eyesight, they often charge when startled.