Hippopotamus' massive body with large head, wide mouth, and long teeth weighs 4,000-8,000 lbs. Although they resemble pigs, the name means "river horse." Native to African wetlands, Hippos play in water or mud during daytime and graze on land by moonlight. Baby hippos are born underwater and swim at birth. Female hippos may baby-sit other hippo babies. Believed to sweat blood, hippos actually secrete pinkish colored oil to cools them and to protect from illnesses.