Hippos are huge herbivores that can weigh up to 8, 000 pounds and measure up to 16 feet in length. They are native to sub-Saharan Africa and are the third largest land mammal after elephants and rhinos. Hippos spend most of their time in the water and feed on grasses and other aquatic plants. They are considered to be one of the most dangerous animals in Africa due to their aggressive nature and sharp teeth.