Bullfrog legs are a source of food for Southern United States and the Midwestern United States. People hunt bullfrogs at night near rivers. The bullfrogs' legs are cooked, while their backs are fried. In China, bullfrogs are sold alive for eating. However, they are later cooked dead with vegetables. In the state of California, people must have a license to catch bullfrogs for food. In schools, bullfrogs are dissected in biology classes. Usually, this is done in grammar school. The dissecting is a method for teaching students the anatomy of a bullfrog. The emperor newt is hunted in China for food. They are also used there for medicine. Burrowing frogs are able to hold water in their bladder, because of this indigenous Australians use them to drink water.