That's what we thought by the shell but the tail is so much shorter. They are the same age but one is way bigger. The bigger one try's to mount everything in the back yard. It drives me crazy.
They are both still immature, but my guess is that the top pic is a male. The bottom one like its leaning female, but do the two of them live together? The presence of a more dominant male will sometime suppress the appearance of secondary sexual characteristics in another male.
Either way it looks like you'll need to wait a little while longer to be sure.
The have the whole backyard to themselves. They do follow each other all over the yard and I find them sleeping right next to each other at night when I get them to Put them away for the night. The big one leads and the little one follows him wagging it's tail.
dont mind the grass sticking out I cleaned it off after I took the pic. The top one is the larger one they told me was a boy the bottom one we think girl