Girl or Boy?
The most common ways of checking the sex of a young gerbil is to either; 1) Turn the gerbil over and check the gap size between the genital organs of the gerbil. Female gerbils have a small gap between the two areas: Males have a much larger gap. 2) Although this is not always clear in childhood and adolescence, male gerbils have a fur covered bulge at the base of their tails, on their underside. This is their scrotal pouch. Females have smooth, round back ends. Males are generally larger than females in adulthood, in length, height and width. You can also sex a gerbil by looking at its underside when it is a blind, deaf baby. Look at his/her underside, and you will see either a thick line in the middle of the stomach (the scent marker) if it is a boy, or eight dots (four on the left side, four on the right), soon to be teats, if it is a girl. The only trouble with this method is that it is difficult to remember which gerbil it was that you identified as a male / female in infancy. On the left, we have a female and on the right we have a male.