The Hippopotamus is a free screensaver created by RateMyScreensaver.com containing 15 high quality photographs. Hippopotamus also sometimes called hippos, are gregarious, living in groups of up to 40 animals, called a pod, herd, school or bloat. A male hippopotamus is known as bull, a female as cow, and a baby as calf. A hippos lifespan is typically 40 to 50 years.