Squamates have enhanced their smell in a way humans could not even begin to fathom. Most animals use their nose to inhale and filter particles, but snakes and other reptiles have developed a special way to use this sense. Many people see a snake’s forked tongue moving in and out of it’s mouth, but never questioned why it would do such an odd thing. This action is the equivalent of a dog sniffing the air. Their tongues have become their noses, flicking out in order to gather particles in the air. Mainly they’re used to detect pheromones, chemical messengers that are emitted from most animals. The tongue will then return inside, pushing to the roof of the mouth where they enter two pits. These pits, known as the Jacobson’s Organ, are a specialized organ inside the mouth, on a palate. There are two, fairly spaced apart, which is why reptiles with extra-sensitive vomeronsal organs have tongues split in two. The bigger the split, the more the species uses their Jacobson’s organ. Many animals, such as lions and house cats, have vomeronsal organs, but do not use them in quite the same way a reptile would.
Photo credit: Snakelover61