The Taureans were a humanoid race that descended from a group of individuals who settled on planet Taurus II when their homeworld began to die.
On Taurus II, they built a temple and numerous other architectural wonders surrounding it. Unfortunately, what these settlers did not know, was that that Taurus II naturally drained humanoid energy.
 Taurean upon arrival  Taurean succumbed to planet's effects |
After living on Taurus II for some time, the female's bodies were able to adapt and develop a glandular secretion that enabled them to survive, functioning at an unusual psychokinesis level. These adaptations allowed them to manipulate certain areas of the males' brains, and influence their emotional senses. This ultimately drained the men, causing them to weaken and die.
The women learned that to survive, they must revitalize their bodies every 27.346 star years, making them eternal prisoners on Taurus II. Capable of neither aging, dying or bearing children.
Once all the men on their planet had died, they resorted to revitalized themselves by means of summoning male crewmembers of starships, from as far as twenty light years away, through the use of their opto-aud.
Beginning as early as 2119, they began luring starships from the Earth-Federation, as well as the Klingon and Romulan Empires. Once lured to the planet, the men were captured and force to wear Taurean headbands, which drain energy from humanoids.
Taurean females entertain the Enterprise landing party
In 2269, the USS Enterprise was investigating several disappearances within range of Taurus II when there fell victim to the Taurean summons.
After the Taurean women were defeated by Lieutenant Uhura and the female crew members of the Enterprise, Theela, leader of the Taurean women, agreed to destroy their opto-aud in exchange to be relocated from Taurus II, by a Federation starship crewed by women, to the first suitable planet. Once relocated, according to Dr. McCoy, the Taurean females would become "normal" once again only after a few months. (TAS: "The Lorelei Signal")