Long story short, once it was on land it turned into a true monster. I eventually succeeded in lifting him off the ground by my fishing line, which was amazingly still intact.
I put four rounds of .380 Remington "Golden Sabre" hollow points in his head at point blank range, and they completely penetrated the length of the body and exited through the shell near his tail, with no apparent result.
We finally got a shovel and turned him over on his back. Six hours later, when my brother-in-law got home from work, he was still squirming around trying to flip himself.
“Six hours later, when my brother-in-law got home from work, he was still squirming around trying to flip himself.”
One of the more interesting labs in one of my neurozoology classes had us drill out the brains of turtles to study their swimming reflex. They’ll go for quite a long time if one is careful with the drill.
On another note, we were out catfishing when one of my buddies hauled up a VERY large snapper on his set line. It was so angry that even after the line was cut, it would move towards us, not the river. I’d believe the self-defense ploy if it was a snapper.