Piranhas are oval-shaped fishes 25 to 60 cm (10 to 24 in) long. They have blunt heads and powerful jaws with sharp, wedge-shaped teeth that cut like razor sharp scissors. They use these teeth to cut the flesh from prey, mostly amphibians, birds, and mammals. Meat-eating piranhas live in large schools and are attracted by commotion and the scent of blood. Once aroused, they can quickly reduce a large mammal to a skeleton. Piranhas live in the Amazon River and other fresh water rivers of South America.