Lizards

A type of reptile, most commonly small and four-legged. They're never referred to directly in Tolkien's tales, but we can be sure they existed in Middle-earth. When Smaug was pondering the mysterious arrival of an invisible Bilbo Baggins in his lair, he decided that the intruder was part of a plot by the Men of the Long Lake. The only alternative, he jokingly concluded, was that he, Smaug the Magnificent, was no more than a plain and simple lizard.