From the Movies
The Nikto were a reptilian humanoid species from the planet Kintan in the Si'Klaata Cluster with many subspecies
They were all reptilian humanoids that were noted for their leathery skin with an average adult standing 1.8 meters tall. Somtimes these were covered in spikes and horns.
The species held a limited range of facial expressions that was because they lacked the necessary infrastructure. All Nikto had cold black obsidian eyes. These were sometimes covered by a protective membrane. This took the form of a thin transparent membrane protected their eyes underwater and during windstorms. As a result, they were noted for their "staring" eyes and a seemingly blank expression which led to many underestimating Nikto intelligence.
The Nikto species featured five distinct mutated sub-species due to a massive radiation from a dying nearby star M'dweshuu, which sped up the rate of mutation so that traits that normally took millions of years to occur instead took only thousands of years. The five sub-species inhabited different geographic areas of Kintan, developing unique adaptations to suit the different environments on the planet.
The varying appearance of the Nikto sub-species caused confusion amongst those who were unfamiliar with the Nikto, but all Nikto had certain similarities; leathery skin, sometimes covered with spikes or horns, as well as eyes that included a protective membrane to shield against Kintan's harsh environment. Lacking the musculature required for complex facial expressions, Nikto were often underestimated in assessments of their intelligence due to their 'staring' eyes and 'blank' expressions.
The mutation caused by the planet's radiation atmosphere were triggered in the race that resulted in five different subspecies that were each adapted to a specific environmental niche. These five reptilian species all displayed unique cosmetic features. While each subspecies of the Nikto was physically distinct and originated from different parts of Kintan, Nikto from different subspecies could easily interbreed. 93% of the offspring from such unions ended up with the characteristics of only one parent's race, with the rest combining the traits of two subspecies.
Behind the Scenes
The Nikto were designed by Creature Supervisor Phil Tippett, first as a maquette, and then as a slip-on mask for a number of background alien extras in Return of the Jedi. The Nikto character, like fellow characters Barada and Klaatu, were named after the 1951 science fiction classic, The Day the Earth Stood Still. In that film, Klaatu, the man from outer space, says the cryptic alien phrase, "Klaatu, Barada, Nikto" in order to control the giant robot, Gort.
During production, Nikto doubled as both a character and species name. It wasn't until later, through Expanded Universe publishing, that it was revealed that Nikto was the species, that Klaatu was a representative of a different Nikto sub-race, and that Barada was a Klatooinian.
The Nikto design was reused for Episodes I and II, this time with new masks. The hand design changed, though, perhaps suggesting yet another Nikto sub-race not yet accounted for.
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