Most fresh water turtles are nasty when cornered and will snap at you, not just snappers. They hurt when they bite as they have beaks with sharp ridges top and bottom in the place of teeth. However, as most cannot swallow unless submerged, they will literally die of hunger if left dry.
When I was little I remember being told that if a turtle bites you it will not let go until it thunders.
I found this to be untrue when my young son was bitten by a turtle. We put antibiotic ointment on the bite and from that day until this we still call it “turtle bite cream”.