Hippos mostly make sounds by grunting and bellowing, sounds which can be made on land or in water. They are the only animals that can do this!
Hippos can't swim or float, they mainly walk along the water bed and are never really seen in deep water.
The name hippopotamus derives from the meaning "river horse" in ancient Greek .
They secrete an oily red substance called "blood sweat" through the skin which is thought to act as sun cream, moisturiser and antibiotic.