A fierce hunter, krayt dragons grow an average length of 147 feet (45 meters) and weight of 44,000lbs (20,000 kilograms). They could live to be 100 years old and could be found on the highest mountains of Tatooine. When summer mating season began, the howls of krayt dragons filled the canyons of Tatooine. Jedi Obi-Wan Kenobi mimicked the hunting cry of a krayt dragon when he scared the tusken raiders away from Luke Skywalker in A New Hope. Krayt dragons have a set of sharp teeth used for capturing prey, but relied on ingesting stones to grind the food through a series of gizzards into a digestible state. Food would be crushed by the stones tumbled inside the gizzards by stomach muscles, grinding food into pulp and turning boulders into smooth stones. The resulting stones, known as dragon pearls, are a valuable commodity among jewelers. The pearls could also be shaped and tuned by Jedi to be used as focusing crystals in their lightsabers.