History and Politics
The head governmental unit of the Tholians was the Tholian Assembly. During the mid-22nd century, the Vulcan High Command had only limited contact with the Assembly. It was, however, unknown at the time that they were involved as a faction in the Temporal Cold War. (ENT: "Future Tense")
First Contact with Earth
In 2152, making an unusual move, the Tholians traveled far beyond their territory; they actively sought to possess a 31st Century time-travel pod discovered by the Earth starship Enterprise. Four Tholian starships intercepted and disabled the Vulcan cruiser Tal'Kir, while it waited to rendezvous with Enterprise. They would, in turn, attack and defeat the Suliban fleet that was in pursuit of the arriving Earth ship. They would then successfully remove the pod from Enterprise's possession, only to have the pod return to its proper timeline moments later. (ENT: "Future Tense")
The Defiant Incident
In a mirror universe, in 2154, the Tholians detonated a tri-cobalt warhead inside the gravity well of a dead star. The explosion created an interphasic rift which acted as a doorway to an alternate universe. Due to its instability, the Tholians reasoned that it was too dangerous to send one of their own ships through, so they transmitted a distress call into the opening, hoping to lure a ship from the other side. (ENT: "In a Mirror, Darkly")
In 2268, the Federation starship USS Defiant would enter this region of space, annexed by the Tholians, in response to the mirror universe distress call. Three weeks later, the starship USS Enterprise would discover the Defiant trapped in a spatial interphase, only to observe the starship, and consequently landing party leader James T. Kirk, cross over into the mirror universe.
Shortly thereafter, two Tholian starships intercepted the Enterprise, demanding that it leave Tholian territory. At the request of First Officer Spock to be allowed to rescue Kirk from the Defiant, Tholian Commander Loskene allowed them a small timeframe, before they were required to withdraw. The Enterprise crew was unable to rescue Kirk in the time provided and the Tholians opened fire, damaging the Enterprise, and then attempted to trap it in their web. The Enterprise, however, was able to recover Kirk and would successfully escaped, before they fell victim to the web. (TOS: "The Tholian Web")
Unknown at the time, the Defiant had traveled back in time to the mirror universe, where, when fully clear of the interphase, it was towed by the Tholians to a small moon dry-dock in the Vintaak system, deep in Tholian space. There they employed several humanoids to gut the ship. (ENT: "In a Mirror, Darkly")
Jonathan Archer learned of the vessels presense in his universe. He commandeered the ISS Enterprise and flew it deep into Tholian space while cloaked to steal the Defiant. After sending a boarding party onboard the Defiant, the Tholians spun a tractor web around the Enterprise and destroyed it. The boarding party managed to activate the Defiant's systems, but not before the Tholians spun a tractor web over the entrance of the dry-dock. The Defiant then destroyed three Tholian ships and the moon's dry-dock, before escaping the system. (ENT: "In a Mirror, Darkly, Part II")
Contact with the Tholians over the next century would be sporadic. In 2353, the Tholians destroyed a Federation starbase. The only survivor of this attack was Kyle Riker, the father of Starfleet Commander William T. Riker. (TNG: "The Icarus Factor")
The frequency of Tholian attacks would remain sufficient enough for Starfleet to develop Tholian-based battle simulations. In 2355, during one such simulation, William T. Riker used a notable strategy to calculate a sensory blind spot on a Tholian vessel. (TNG: "Peak Performance")
They would remain a threat well into the 2360s, when it was anticipated by Klingon Special Emissary K'Ehleyr that if a Klingon Civil War were to break out in 2367, the Tholians might eventually be involved. This fear, however, did not come to light when the civil war broke out months later. (TNG: "Reunion")
Trade and Diplomacy
The Tholians conducted business with Bajoran trader Razka Karn in the early 2370s. They pursued him because of unscrupulous "business" practices so he took refuge in the Badlands. (DS9: "Indiscretion")
The Tholians maintained ambassadors with other powers throughout the Alpha Quadrant. In 2371, a Tholian ambassador visiting DS9 reported that someone broke into his quarters during the night and stole three cases of latinum. (DS9: "Defiant")
The following year, a Tholian observer was killed in the bombing of the Antwerp Conference on Earth by a Dominion infiltrator. (DS9: "Homefront") Despite this, the Tholians would sign a non-aggression pact with the Dominion the following year, prior to the outbreak of Dominion War, remaining neutral throughout the conflict. (DS9: "Call to Arms")
In 2379, Romulan Senator Tal'aura had an appointment with the Tholian ambassador to Romulus, conveniently causing her to leave the Senate chambers only moments before the assassination of the entire Senate. (Star Trek: Nemesis)
A living Tholian is approximately the same height as a human. It is principally a reddish color, in varying shades, and there is a suggestion of fluid or field motion within the body. Tholians have a hard carapace that is chiefly mineral. There are six thin legs that permit the being to move in any direction quickly; the legs are articulated with joints roughly corresponding to the knee and ankle of humanoid species. Each is terminated in a multi-toed foot. The legs attach at the base of the torso and are radially symmetric. There are two arms; each has joints analogous to the humanoid elbow and wrist, and each terminates in a multi-fingered hand. There is no neck; the term "head" may not apply. Tholians do have two glowing spots near the top of the torso. They orient these to face individuals with whom they interact, suggesting they are some sort of information gathering organ. Tholians have two sexes, but each individual has both sets of sexual organs. (ENT: "In a Mirror, Darkly")
- The presence of two distinct sexes means Tholians are not parthenogenetic, and probably that they cannot self-fertilize.
Tholians exist at high temperatures — in excess of 450 Kelvin (178°C, 350°F). They can tolerate lower temperatures briefly; if they are exposed to temperatures too low, their carapace will crack. This is evidently painful or distressing; a Tholian subjected to this temperature can be coerced to cooperate. In temperatures still lower, a Tholian will freeze solid and shatter. (ENT: "Future Tense", "In a Mirror, Darkly")
Tholians evidently have something analogous to biochemical processes. Phlox from the mirror universe was able to devise a sedative, however, this compound eventually lost effectiveness. (ENT: "In a Mirror, Darkly")
- This suggests that Tholians have an immune system capable of combating toxic hazards.
Tholians are naturally able to emit various forms of radiation, which they can modulate. They can communicate over short distances in this fashion. A Tholian imprisoned aboard the ISS Enterprise (NX-01) in 2155 was able to summon help via this method, forcing Phlox to kill it in order to silence it. (ENT: "In a Mirror, Darkly")
- Tholians communicate primarily through a series of clicks and chirps, similar to the language of Xindi-Insectoids.
- This seems to imply that Tholians could be infected by pathogens, indicating that they have a cellular structure of some kind.
Society and Culture
During several confrontations with the Federation, Tholian behavior could best be described as aggressive and territorial. They rarely advanced very far from their home system and would frequently annex surrounding systems outside of the Assembly, to further isolate their territory. Tholians are also renowned for their punctuality. (ENT: "Future Tense", "In a Mirror, Darkly"; TOS: "The Tholian Web"; DS9: "For the Cause")
Tholian weddings involve paying a dowry. Furthermore, Tholian silk is highly prized and is a difficult commodity to obtain. A Tholian ambassador owed Benjamin Sisko a favor and obtained silk for him. (DS9: "Defiant", "The Way of the Warrior")