The Hippopotamus is a large mammal from swampy areas, lakes, and rivers south of the Sahara desert in Africa. It is semi-aquatic, spending much of its time in the water. Hippos can stay underwater for up to 6 minutes. Bull Hippos (adult males) often fight each other, using their enormous canine teeth as weapons. Hippo cows give birth in the water. Its gestation period is 8 month. Hippo have a life span of 40 years.