Xantoran (Sanctuary)

The Xantorans are a sentient species native to the planet Xantor. The atmosphere on Xantor was extremely dense, so Xantorans evolved to survive under great pressures. This meant that Xantorans would decompress and die in low pressure environments. Thus, the few Xantorans that left Xantor wore special protective suits. Very few non-Xantorans ever saw a Xantoran without the suit on, though they were believed to look somewhat like Humans with a more sickly colored skin.