Jirellans are bipedal humanoids, physiologically similar to humans, Garmillas, and other species that can trace their genetic ancestry to the ancient alien race called Aquarius. They are visibly distinguished by light gray skin and long pointed ears, and Jirel of all ages have gray hair. However, they are best known for their strong telepathic abilities. Jirel can project complete thoughts and emotions telepathically among themselves and to outsiders. They can also read the minds of those around them without their cooperation. Contact can be made with multiple individuals simultaneously and over extended periods, and can be used to create vivid, detailed, and believable hallucinations ("The Whisper of the Witch", "The Forever War", Space Battleship Yamato 2199: Odyssey of the Celestial Ark