They are known to have shared a similar internal physiology with Vulcans and Romulans. These similarities, notably to Vulcans, included similar blood chemistries. Rigelians also shared a similar neurology to Vulcans and Romulans, as they too were susceptible to the neurological disease known as Tuvan Syndrome. (TOS: "Journey to Babel"; DS9: "Inter Arma Enim Silent Leges")
History and politics
Relationships with other species
Later that year, three Rigelians visiting Earth, who were working for the Klingons, attacked and kidnapped Dr. Phlox from the streets of San Francisco. They later transferred him via a Rigelian freighter to a Klingon ship. The Rigelian kidnappers and their ship were later destroyed. (ENT: "Affliction")
In 2154, a Rigellian scoutship fell victim to an attack by a Romulan drone ship which disguised itself as Earth starship Enterprise in order to destabilize the sector. Recognizing the vessel, the Trade Commission contacted Starfleet to demand compensation for the loss of their vessel and the arrest of Enterprise's commanding officer, Captain Jonathan Archer. (ENT: "United")
In early 2155, the Rigelians participated in talks discussing their wish to join as a possible member in the Coalition of Planets along with Humans, Tellarites, Andorians, Coridanites, and Vulcans. (ENT: "Demons", "Terra Prime") During the negotiations, six of the Earth universal translators experienced a "glitch" and started confusing the Rigelian language with Andorian. (ENT: "Demons")
Trade and commerce
During the mid-2260s, an experimental chemical stimulant designed to speed up reproduction and replacement of blood in the bodies of certain species was developed and successfully tested on Rigelian test subjects on the planet Rigel V. Although the side-effects included tremendous strain on the spleen and the liver, it was later discovered by Doctor Leonard McCoy to be a viable treatment for producing Vulcan T-negative blood. (TOS: "Journey to Babel")
The species name was spelled both as "Rigelian" and "Rigellian" in scripts, but in those few episodes in which they appear, the same make-up was used regardless of spelling. The name Rigellian was also given by behind the scene sources to a turtle-like species developed for a crowd scene in Star Trek: The Motion Picture.
The Rigelians are a playable species for the Federation in the game Star Trek Online.
- The Chelons, a species of tortoise-like reptiles native to Rigel III. These were the Rigellians from Star Trek: The Motion Picture.
- The Jelna, humanoids native to Rigel V. They had four sexes and were the first Rigelian species to achieve spaceflight. These were the Rigelians seen in Star Trek: Enterprise and Star Trek Online.
- The Zami, humanoids native to Rigel IV, but who had also colonized Rigel V. They resembled Humans with slightly pointed ears and had a biochemistry similar to Vulcans. These were the Rigelians mentioned in "Journey to Babel" and "Inter Arma Enim Silent Leges". The Kalar were a subspecies of Zami.
All Rigelian species were politically united and the Rigel system was considered to be a crowded and bustling population center in the novels, with its three native species and numerous colonists from other species.