Instructions
Set a feeding schedule to follow for at least one week. For example, feed your blue-tongue at 5 p.m. every day.
Take your lizard out of its cage about noon each day so you can watch it defecate.
Observe your pet while it defecates. In a skink as young as three months old you may see the male's hemipenes pop out while it defecates. The hemipenes are the male sex organs of a lizard. They are located on either side of the tail base and slightly under the tail.
Inspect the feces of the lizard to see if it left behind a sperm plug. If you have not seen the hemipenes, the sperm plug is another sure sign that you have a male blue-tongued skink. The sperm plug resembles a small ball of mucus with a thin tail or simply a strand of mucus. Although males may start to produce sperm plugs as early as six months of age, it is more likely to happen when the lizard is closer to 1 year old.
How to Tell If a Blue-Tongued Lizard Is Male or Female
Sexing lizards can be difficult, but according to Zach Griffith, an expert on blue-tongued lizards (also known as blue-tongue skinks), it's a matter of knowing what to look for. Although you could place two lizards, at least 1 year old, into a the cage to observe their behavior -- males fight, females ignore each other and at the right time of year two of opposite sexes may mate -- there are other things you can do to look determine the sex of your lizard. Griffith says the best way to determine the sex of your lizard is to watch it defecate.