I have lived with many iguanas over the years, but Stella, a green iguana, is the only one who constantly sticks her tongue out. I’m always afraid I’ll startle her and she’ll cut her tongue with her razor sharp teeth. Fortunately, that has never happened. Her tongue is intact.
So, why is her tongue always sticking out? She’s tasting or “smelling” the world around her. Iguanas don’t smell with their noses like people do. They “taste” the world. Scent particles in the air are collected on the tongue, then brought into the mouth. The particles are analyzed by special sensory cells for identification. These cells make up the Jacobson’s or vomeronasal organ. If you watch an iguana walking, you’ll see her flicking her tongue out. If something is particularly interesting, say a tasty bit of food, the tongue flicks back and forth a lot.
Another interesting thing about iguana tongues is that they are forked! Just like a snake’s tongue. You might also notice that the end of Stella’s tongue is darker. That’s because it is more enriched with blood. The better for tasting!