Rancors were large semi-sentient reptilian carnivores native to the planet Dathomir.

Standing around five meters tall, with their long arms, immense jaws, and armored hides that could withstand blaster fire, they were formidable predators. A subspecies known as the jungle rancor populated the planet Felucia. Rage rancors were taller and had an even nastier temperament than an average rancor. Shadow rancors were notorious for their penchant for destruction, gaining their name from their black skin. The proper term for a group of rancors in Galactic Basic Standard was a crash of rancors.

Rancors responded to a social hierarchy where an alpha was dominant over other rancors unless defeated. Despite their extremely intimidating appearance, the creatures were inherently benign and were even domesticated by the Witches of Dathomir, but could be provoked over time into a violent nature. The dirty teeth of the rancor were cleaned by birds. Rancors would eat anything that they were capable of getting their hands on.

Rancors were often bred for fighting. However, when domesticated, they could be very loving to their owners.