The long-tailed grass lizard (Takydromus sexlineatus), known also as the Asian grass lizard and other names, is an unusual little critter with an elegant, long tail that may be as much as three times the length of the lizard's body. Because distinct external differences exist between boys and girls, sexing mature specimens isn’t difficult.
Look and Learn
A male long-tailed grass lizard has obvious genitalia that you can see if you'll turn the creature over and look. To do so, gently grasp the lizard’s body well away from the prehensile tail, which falls off easily, and turn your pet over to get a good look at the belly. Check for hemipenal bulges where the abdomen meets the tail. Female grass lizards lack these structures. Examine the one or two distinct bumps, or femoral pores, on the underside of each thigh near the base of the tail. The pores are darker in color on females than the surrounding tissue is in males. They’re much less visible in females, which have duller coloring overall.