I'm thinking female judging from the distance of the opening to the shell, males seem much farther to me, and the width of the base. Turtle is 3.75". To small? Opinions?
Mike if I hadn't eaten in a week I'd still bet my lunch money on that tail belongs to a Male Northern Diamondback Terrapin.. even tho' it's less than 4". Look at the length of that tail!
Since words and a dollar might get you a cup of coffee.. I'll include comparison pics for you.
Less than 4" male -
4" Female -
Even tho' 4" or less is still small to really sex.. it makes it easier if you have two to compare. The female will show a larger/broader head also.
Not to mention.. 4" males are young mature males - 4" females are half grown/mature at best.