I see large turtles on my property on a regular basis. Most of the time after a heavy rain you will see a female hovering over a hole that she has dug in the soft ground dropping eggs (see picture). She then covers the eggs with mud never to return.
Our dog found one a little bigger than that
last year and decided to take a sniff. Faster then the eye could see, he found out exactly how they got their name. Nice size chunk off the tip.... he don't bother the turtles any more!
I was watching the whole thing from a distance trying to get his attention away from the turtle but he is a little thick headed sometimes. It was truly within a blink of an eye that he got nipped. I didn't even realize the turtle had done anything to him until I saw the blood gushing from his face. Amazing a cold blooded animal can move that fast!