Hippos are very rotund animals and are the third largest living land mammals, after elephants and white rhinos, according to Animal Planet. They grow to between 10.8 and 16.5 feet (3.3 to 5 meters) long and up to 5.2 feet (1.6 m) tall at the shoulder. The average female weighs around 3,000 lbs. (1,400 kilograms), while males weigh 3,500 to 9,920 lbs. (1,600 to 4,500 kg), according to the San Diego Zoo.