I have experience with snappers of both species from handling and caring for them in other´s people colections. What you said about their behavior is rigth, however if something goes between their jaws... Zoos here have big AST on display, all have incomplete tails because they insist on keeping them together. I know a guy in spain that has a pond with several huge ones and all bear scars. Keeping them with inquisitive, less armored turtles such as sliders and softies is asking for disaster. Please put them apart asap.