Snapping turtles are on my list as part of a survival stew,much better than Rat!!.the lakes in Northern Minnesota are full of them and like this one finding them wandering around the woods between lakes is not unusual.
Hard to gauge scale but that snapper looks like a good sized one. Shell looks to be most of a foot long. About big enough to make a nice meal for two. Or take a finger, or three, if you don't watch out. Down here a lot of kids grow up surrounded by concrete and large snappers are an accident waiting to happen. Those smart enough to recognize the hissing and gaping jaws, big enough to fit a baseball in, as dangerous often don't realize exactly how far a snapper's neck can stretch. Easy to get a free manicure, all the way to the second knuckle. Another reason many country boys can't do math.
I don't know the official figure is but I estimate that their reach is pretty much the length of their shell measured from the head end of the shell. With head retracted people get fooled into coming too close. And once they bite they are quite stubborn about hanging on. Good way to loose a finger or three.
No great harm experimenting as long as you use a stick.
Another interesting effect is that snapping turtles are often inhabited by leeches. A friend killed a couple of snappers and went on fishing. He was horrified when he found a couple of leeches climbing up his leg and another half dozen making tracks toward him. He just about lost it.
Leeches lose interest in dead bodies so they went looking for a warm one. In the boat he was 'it'. Funny how some grow men get freaked out by leeches. Charge into NK with nothing but a can of peaches and a P-38 ... no problem. Leeches ... forget about it. Can't handle it. LOL.