text: Vulcans , or sometimes Vulcanians , are a fictional extraterrestrial humanoid species in the Star Trek universe who evolved on the planet Vulcan , and are noted for their attempt to live by reason and logic with no interference from emotion .
simplified: Vulcans are a humanoid species in the fictional Star Trek universe who hail from the planet Vulcan , and are noted for their attempt to live by reason and logic with no interference from emotion .