Last June, we saw a fairly large turtle in the courtyard at Martinique. My kids were afraid that it was going to get to the parking lot and not be able to make it back to the water, but a cm assured me that it is fairly common and bus drivers know to look out for them and to call someone to come and get them if they are in the parking lot or on the roads and get them safely back to water. A word of caution: don't try to touch them, they are snappers!
As for other wildlife, we saw rabbits every morning in the courtyard. Ducks were everywhere, especially near the food court where people would feed them. The guests were often surprised that they couldn't get rid of the ducks; it seems once you feed a duck you have a friend for life!
CBR is a beautiful resort. We'll be enjoying it again soon!