The Rodians of planet Rodia are a species of green-skinned humanoids found throughout the galaxy. They have large, black eyes, tapir-like snouts, long flexible fingers terminating in suction cups, twin saucer-like sensory organs atop their heads, and a ridge of spines cresting their skulls. Rodians can be found among the Core World elite -- like Senator Onaconda Farr or Supreme Chancellor Palpatine's aide, Dar Wac -- to the lowest of the Outer Rim fringe -- like the bounty hunter Greedo.
Rodians evolved as hunters, killing much of the wildlife and predacious species on their planet to extinction. The Rodians grew restless with nothing to hunt, and turned to hunting each other in gladiatorial combat. One of the greatest of the Rodian Grand Protectors called an end to this self-slaughter around the time that Republic ships made contact with the species. The Grand Protector saw the expansion into the galaxy as an opportunity for the Rodians to hunt new species and targets.
As a result, many Rodians have taken to bounty hunting. Many take on contracts as part of grand games and contests, caring nothing for the concept of law enforcement. Rodian society awards bounty hunting in a wide variety of categories -- Longest Trail, Most Notorious Capture, Best Shot and more. Because some Rodians have taken to padding their hunts by allowing their quarries to commit further crimes, increasing their bounties, these aliens have a shady reputation. This, combined with the pungent pheremones that Rodians naturally exude, has fomented an increasingly common intolerence towards their kind.
Despite the Rodian thirst for violence and a history marked by interclan wars, the Rodians have a rich culture. Harido Kavila, a renowned Rodian Grand Protector, further attempted to steer the violent tendencies of the Rodian people into a more constructive direction by encouraging the production of drama. Rodian theater works are now among the most poignant, well-respected, and violent productions in the galaxy.
Costume Designer John Mollo's sketches for the three Rodians present in the Mos Eisley Cantina referred to them as "Martians." According to his sketches, the Rodian masks were at one time to fit a four-armed body, which would eventually be known as a Morseerian (his sketches call it a "Plutonian"). The heads were switched before filming.
Though the terms Rodian and Rodia were first developed for the Expanded Universe in a roleplaying sourcebook in 1989, the name stuck, and saw its way into production for the prequel trilogy.