The Andorians were a warp-capable humanoid species from the moon Andoria, capital of the Andorian Empire. In 2161, their homeworld became a founding member of the United Federation of Planets.
Most Andorians were blue-skinned with white or silver hair. An Andorian subspecies called the Aenar had white skin and, unlike blue Andorians, were blind and telepathic. Andorians and Aenar were genetically compatible and could produce offspring.
Andorians, with a higher metabolic rate than Terrans, were especially vulnerable to phase pulse infection; even minor phase injuries could prove fatal. However, they have demonstrated resistance to a wide range of environmental conditions. In a climate where the temperature is near the boiling point of water, an Andorian could still thrive, despite losing 10% of their body weight in two days.