It's not just iconic characters like Kirk, Spock, and Janeway that have made "Star Trek" one of the best science fiction franchises of all time. It's also its memorable alien races like the Klingons, ...

Some of the most famous alien races in all of science fiction originate in the "Star Trek" universe. From the violent, war-mongering Klingons to the silly, furry Tribbles, there are any number of ...

With tons of "Star Trek" alien races depicted over the decades, consistency is a tall order. And in the case of these aliens, major changes went unexplained.