The rancor is a huge bipedal reptomammalian creature from the Star Wars universe. These ferocious beasts were originally from the planet Dathomir, standing strong as that world's apex predator, but over time they would be introduced to other worlds such as Felucia and Carida. Commonly misconceived as being purely savage, rancors are actually semi-sentient, capable of learning certain complex tasks and passing that knowledge down to their young. Some rancors have even displayed an ability to read and write.
Warm-blooded rancors fell into the reptomammal category, along with other creatures such as the wampa. Rancors were attracted to other rancor mates by a smell, or a pheromone. While it is known that rancors did care for their young—usually born two at a time—they did not suckle and hatched from eggs like those of a reptile. The 3 meter tall hatchlings rode the mother, one dorsal, one ventral, until reaching maturity, though despite this nurturing nature, it was not entirely unheard of for a mother to eat her young.
Rancors walked on two relatively stubby legs, with longer forelimbs utilized for catching prey, though they also walked on all fours at times and had a short tail. A rancor's flat face was dominated by a large mouth full of razor sharp teeth. Although it had sharp teeth, it would often swallow smaller prey (such as humanoids) whole. The skin of a rancor was tough enough to deflect blaster bolts, making it an efficient killing machine—and an excellent source of leather for expensive vests and boots. At least on Dathomir, rancors had good night-vision, but their eyesight was not as sharp as a Human's in daylight. Rancors had a symbiotic relationship with gibbit birds, an avian species that would clean their teeth, an action that provided the birds with food and the rancors with a form of "dental hygiene."
A large variety of rancor subspecies exist on various planets which have been listed below.