How Do You Tell The Sex Of A Lizard After You Buy It?

You have to flip the lizard on it's back. To know it is male lizard, just see swelling at the base of the tail near the cloaca (anus). With time you can judge that, but it is also not necessary with all male lizards.

In general males have more heavy bodies than females and their heads are broad and necks are thicker.

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Lizard Sex

That depends on the species, Leopard Geckos and Bearded dragons look just above the anal slit and if it's a male you will see 2 predominate bumps which would be the testes of the male ,females are smooth.