It is quite difficult to find male res nowadays. In my breeding group, gamay ra kaau ang percentage sa males as compared to females. males are distinguished by their wolverine claws (tag-as) and sometimes they tend to fall into the RES dark phase (2 of my RES males are dark phase), Males also tend to be smaller as only females reach a carapce length of 1 ft. plus. Dont rely on the tail length for sliders...they can be decieving and so with the male plastron notch. I wouldnt recommend these indicators...tooo tricky.