Hippos are large, semi-aquatic mammals native to sub-Saharan Africa, known for being highly social, territorial, and aggressive. They are herbivorous, with common hippos weighing up to five tons and pygmy hippos being smaller and living in West African rainforests. Their massive jaws and powerful bite make them one of Africa's most dangerous animals. Hippos are considered vital to their ecosystems, as they help create habitats and fertilize the water through their waste.