When I was young, my father and his friends would occasionally go to specific areas to capture snapping turtles for turtle and blood soup. They caught some very large snappers. When they would dress them out and clean them, the kids would take the hearts and put them in a glass of water, and it would keep beating for hours. Also, as mentioned above, a couple hours later, you could poke the severed head with a stick and the mouth would snap at the stick. As children, we got quite a kick out of that. I did not like the soup. Truly amazing, pre-historic creatures of survival.