I guess I should stand farther back

.
edit: Every page I can find with info on water moccasins gives info that doesn't fit any of those 3.
1) water moccasins swim such that they're on top of the water (see the picture linked
here).
2) slit-shaped pupils instead of round ones. Both 1 and 3 have circular pupils (you can't see it in the pic of 3, but i have more that make it obvious)
3) pitlike depressions behind the nostrils.
I don't see anything I'd describe that way (warning: big file).
4) they open their mouths when scared. none of the snakes did that.
5) the tails weren't short and stubby (see 1b and 1c)
6) the head wasn't angled at 45 degrees when it was on land
google results
interesting pdf