(covers information from several alternate timelines)
|Sarek, a male Vulcan (2293)|
|T'Pau, a female Vulcan and Syrrannite (2154)|
The Vulcans or Vulcanians were a warp capable humanoid species from the planet Vulcan. They are widely known for their logical minds and stoic culture. In 2161, their homeworld became a founding member of the United Federation of Planets.
History and politics
- See also: Vulcan history
Commander Spock once theorized that Sargon's people may have colonized Vulcan some half a million years ago. Sargon believed that Humans and Vulcans might even be descendants of their early travelers. (TOS: "Return to Tomorrow")
With the discovery of ancient humanoid progenitors in the 24th century, most humanoid lifeforms in the known galaxy were found to have a "seed" genetic code guiding their evolution to the humanoid form. (TNG: "The Chase")
Culturally one of the most fascinating species in the Federation, the Vulcans were once an extremely violent and emotional people (even by Earth standards) who waged almost constant warfare on one another. (TOS: "Balance of Terror"; VOY: "Random Thoughts") Paranoia and homicidal rage were common. (ENT: "Impulse") They believed in a variety of gods, such as war, peace and death. (TNG: "Gambit, Part II") As their level of technology improved, the Vulcans eventually reached a point where their violent nature threatened species extinction. (ENT: "Awakening")
In an effort to avoid this fate, a Vulcan named Surak developed a new philosophy thereby igniting the Time of Awakening. Surak maintained that the root cause of all the problems on Vulcan lay in the uncontrolled outpouring of the people's emotions. His followers swore to live their lives by an ethical system devised by Surak and based purely on logical principles. Emotions were to be controlled and repressed. (TAS: "Yesteryear")
Although this new philosophy spread rapidly across Vulcan, a minority, many of whom were known as "those who march beneath the Raptor's wings", rejected Surak's ideals. A destructive war began including the use of atomic bombs and among the victims was Surak himself. (ENT: "The Forge", "Awakening")
Eventually, however, those who opposed logic left Vulcan and founded colonies elsewhere (TNG: "Gambit, Part I", "Gambit, Part II") – most notably on the planet Romulus, where they founded what eventually became the Romulan Star Empire. (TOS: "Balance of Terror", "The Enterprise Incident"; TNG: "Unification I", "Unification II") At some point in history, the Romulans and the Vulcans engaged in a hundred-year long war against one another. The war was instigated by the actions of a member of the Q Continuum. (VOY: "Death Wish")
Another group that rejected Surak's philosophy was known as the "V'tosh ka'tur" or "Vulcans without logic". The V'tosh ka'tur believed in controlling emotions by allowing themselves to actively experience them rather than suppressing them. Many of these also left Vulcan, and took up a nomadic existence. (ENT: "Fusion")
At least one planet studied by the Federation was inhabited by "proto-Vulcan humanoids" without warp technology or any direct ties to the Vulcans or the Romulans. The Mintakans possessed technology identified as Bronze Age, but their culture was described by Federation scientists as generally peaceful and highly logical, much like their Vulcan brethren. Eventually, an error during a Federation science mission led to the exposure of Mintakans to Federation technology and society, exempting them from the Prime Directive. (TNG: "Who Watches The Watchers")
The Vulcans conducted a series of survey missions to the Sol system, as early as 1957. (ENT: "Carbon Creek"). Vulcans were in fact one of the first species to develop warp drive, though a century passed between the first warp flight and the breaking of the warp 2 barrier. (ENT: "First Flight") T'Pol told Archer that Vulcans "don't share" Humans' "enthusiasm for space exploration," but a Syrrannite on Vulcan advised Archer that this may not be true. (ENT: "Fight or Flight", "The Forge")
The official First Contact between Vulcans and Humans came on April 5, 2063 when a Vulcan survey ship detected the warp flight of Zefram Cochrane's Phoenix. The Vulcans met with Cochrane at his launch site on the day following the flight. (Star Trek: First Contact)
The Vulcans eventually became Earth's "big brothers" in a way, advising Earth officials on how to proceed into the galaxy. The Vulcan High Command considered Humans volatile and similar to Vulcans before the Time of Awakening, and so attempted to slow down Humanity's move into the galaxy until the time was right. (ENT: "Broken Bow", "The Forge")
In contrast to their tradition of peaceful exploration, the Vulcans had a long history of border skirmishes with the neighboring Andorians. The Humans helped negotiate a peace between the two over the disputed Class D planetoid, known to the Vulcans as Paan Mokar. (ENT: "Cease Fire")
In the 22nd century, the Vulcan High Command, once in charge only of space exploration and planetary defense, gained much more control over civilian affairs. Under the High Command's leadership, Vulcan policy toward other planets became more aggressive and interventionist, using the ancient monastery at P'Jem to spy on Andorian activities. (ENT: "The Andorian Incident")
Vulcan also became less tolerant of political and philosophical challenges towards the High Command's operations, notably engaging in purges of the Syrrannite group, who claimed that Vulcan society was no longer following the teachings of Surak. These tensions came to a head in the crisis called the Vulcan Reformation, which resulted in the overthrow of the High Command (and its leader, V'Las, who was secretly allied with the Romulans) and a restructuring of the Vulcan government under the leadership of Kuvak and T'Pau. One of the first acts of the new government was to end the policy of holding back Human expansion into the galaxy. (ENT: "The Forge", "Awakening", "Kir'Shara")
By the 24th century, Vulcan remained one of the principal Federation members, and was deeply involved in all levels of that society. Their tradition of exploration continued; in the 24th century, a Vulcan ship was the first to make formal contact with a Gamma Quadrant civilization, upon encountering the Wadi. (DS9: "Move Along Home") They were at the forefront of exploration in the Gamma Quadrant, encountering the Rakhari and finding the remains of the Hur'q civilization. (DS9: "Vortex", "The Sword of Kahless")
Despite the enmity between the Federation and the Romulan Star Empire, some Vulcans attempted to forge a more cordial relationship with their cousins, ultimately hoping to reunify the two cultures. Many of these efforts met with little success. (TNG: "Unification I", "Unification II") In the wake of the Reman uprising, as well as the improved relations between the Romulans and the Federation after the Dominion War, it was unclear what the status of this movement was.
History turned out much differently for the Vulcans of the mirror universe. When the Vulcans made first contact with Earth of this universe in 2063, Zefram Cochrane shot the first Vulcan to publicly set foot on Terran soil, believing his vessel to be the vanguard of an intended invasion. The Terrans stormed the T'Plana-Hath and studied Vulcan technology. Eventually, the Terran Empire was able to conquer the Vulcans. (ENT: "In a Mirror, Darkly")
By the 2150s, Vulcans were considered slaves to Humans and not treated as equals. A number of Vulcans and Vulcan ships rebelled against the Terran Empire, but by 2267, their attempts seem to have been unsuccessful. By that time, however, it appeared that Vulcans, such as Spock, were treated with more respect and feared by some Terrans. (ENT: "In a Mirror, Darkly, Part II"; TOS: "Mirror, Mirror")
In an alternate reality, the planet Vulcan was destroyed by the Romulan Nero in 2258. Over six billion Vulcans were killed, with an estimated 10,000 survivors. After witnessing the atrocity, Spock noted in his log that the Vulcan species had become endangered. (Star Trek) Spock's prime reality counterpart founded a colony for the survivors, which by the following year had been settled and named New Vulcan. (Star Trek Into Darkness)
Externally, Vulcans were generally similar to Humans, the chief exceptions being the Vulcans' notably arched and up-swept eyebrows and distinguished external ear structure, the top of which tapered into a clearly defined point.
Most Vulcans had straight, glossy dark brown or, more commonly, black hair and pale skin with a very subtle greenish tinge, much as the skin of Humans of European descent had a very subtle reddish or pinkish tinge. However, some Vulcans, including Tuvok, had brown skin, tightly coiled black hair, and physiognomic features similar to those found in Humans of African descent.
Others shared physiognomic features similar to those found in Humans of East Asian descent. However, most Vulcans had a vaguely Eurasian appearance. (Star Trek: The Original Series; Star Trek III: The Search for Spock; Star Trek: Voyager)
Vulcans had body hair similar to Humans, and some males could be very hirsute. Vulcan males were also capable of growing facial hair (as evidenced by Sybok and both Spock and Soval in the mirror universe), but rarely did so. (TOS: "Mirror, Mirror"; Star Trek V: The Final Frontier; VOY: "Gravity"; ENT: "In a Mirror, Darkly, Part II"; Star Trek)
Vulcans possessed teeth that Humans did not have. These included anterior tricuspids, the presence of which implied that Vulcans also had posterior tricuspids. Vulcan teeth may have been chemically capped, as Human teeth may have been since the 20th century, in order to prevent decay. (ENT: "Dear Doctor")
In contrast to their external similarities, Vulcan internal anatomy differed radically from that of Humans. For instance, their heart was where a Human's liver would normally be, (TOS: "Mudd's Women", "A Private Little War") and beat several hundred times per minute. (TOS: "The Naked Time", "Journey to Babel") They also had no appendix. (TOS: "Operation -- Annihilate!")
Vulcan blood was copper-based and was copper- or rust-colored when deoxygenated in the veins and green when oxygenated in the arteries (although it is unclear if this transport mechanism was a hemocyanin as in Earth molluscs). Bruises and dermal abrasions took on a greenish color. (TOS: "The Naked Time", "Patterns of Force"; DS9: "Field of Fire"; VOY: "Repression"; ENT: "In a Mirror, Darkly, Part II"); (see also hemocyanin at Wikipedia)
Vulcans possessed a highly efficient respiratory system to extract the oxygen they needed from Vulcan's thin atmosphere. They were most comfortable in high temperatures, which was natural given the hot, arid climate of their homeworld. A Vulcan of advanced age may become more sensitive to lower temperatures. (TOS: "The Deadly Years"; ENT: "The Forge")
The Vulcan digestive tract was highly adaptable. Although alien foods, notably Human food, would occasionally disagree with a Vulcan, given time, their body could adapt to the alien food. (ENT: "Unexpected")
Vulcan hearing was very sensitive. (TOS: "Return to Tomorrow", "The Way to Eden"; ENT: "Singularity") Vulcan females possessed a heightened sense of smell. (ENT: "Broken Bow", "The Andorian Incident")
Having evolved on a planet which was mostly desert, Vulcans developed ways of surviving in desert conditions. For example, they could survive for several days without water and had inner eyelids which protected their eyes. (TOS: "Operation -- Annihilate!"; ENT: "Strange New World", "The Forge")
Vulcans had a superior metabolism to Humans. Caffeine and sapotoxins had little effect on them. (ENT: "Breaking the Ice") They were also capable of surviving for long durations without food or sleep. Under stress, Vulcans could do without sleep for weeks. (TOS: "The Paradise Syndrome") Tuvok once claimed that as a Vulcan he was capable of going without sleep for two weeks, (VOY: "Muse") although shortly after making this claim he was observed to fall asleep in the command chair after having gone a little over ten days without sleep.
Perhaps the most interesting aspect of the Vulcan physiology was the brain. The Vulcan brain was described as "a puzzle, wrapped inside an enigma, housed inside a cranium." (VOY: "Riddles") This had some basis in fact, as the Vulcan brain was composed of many layers.
It was in direct control of most of the bodily functions, acting as a control unit for many organs. Despite this, a Vulcan body from which the brain had been removed was capable of functioning and even walking around (albeit in a zombie-like state) with a portable life support system. (TOS: "Spock's Brain")
Unlike most humanoid species, traumatic memories were not only psychologically disturbing to Vulcans, but had physical consequences as well. The Vulcan brain, in reordering neural pathways, could literally lobotomize itself. (VOY: "Flashback")
Vulcans learned to gain conscious control of many of these functions, allowing them to regulate their bodies to a high degree by simple will power. When injured a Vulcan could go into a trance-like state, using this ability to concentrate all of his or her energy onto repairing the injury. (TOS: "A Private Little War")
This trance could be self-induced and gave the physical appearance of near-death. It was similar, in principle, to Vulcan neuropressure techniques which could be used to relax the mind and body. (TOS: "By Any Other Name"; VOY: "Riddles"; ENT: "The Xindi")
The substance trellium-D acted as a neurotoxin to Vulcans, destroying the neural pathways which controlled their emotions. Treatment had to be provided quickly after exposure, otherwise the damage was irreversible. (ENT: "Impulse")
The most famous aspect of the Vulcan brain was the inherent telepathic abilities, such as the Vulcan mind meld. Vulcans were natural touch-telepaths. Though considerable training was required to utilize this ability to the fullest (this would be performing the fal-tor-pan), simpler contacts did not require any concentration, training or even conscious knowledge of the act. (VOY: "Blood Fever")
Stronger minds were capable of non-contact telepathic projection and scanning, usually over short distances, (TOS: "The Devil in the Dark", "The Omega Glory"; VOY: "Random Thoughts", "Prey") but sometimes even over interstellar distances. (TOS: "The Immunity Syndrome"; Star Trek: The Motion Picture)
Another psionic ability of the Vulcan race was the telepathic suggestion or compulsion, consciously performed by Spock, (TOS: "A Taste of Armageddon", "The Omega Glory") Sybok, (Star Trek V: The Final Frontier) Tuvok, (VOY: "Repression") and T'Pol, (ENT: "In a Mirror, Darkly") and unconsciously performed by Sarek. (TNG: "Sarek")
Besides the Trill, who achieved this through the zhian'tara ritual, Vulcans were the only other known humanoid race capable of performing a synaptic pattern displacement, or the transfer of one individual's consciousness into another. Similar feats were also performed by the people of Sargon's planet, Janice Lester, Dr. Ira Graves, Rao Vantika, and Tieran, though they used technology instead of psionic abilities to achieve it. (TOS: "Return to Tomorrow", "Turnabout Intruder"; Star Trek III: The Search for Spock; TNG: "The Schizoid Man"; VOY: "Warlord"; DS9: "The Passenger", "Facets")
Approximately every seven years, adult Vulcans had to endure pon farr, the Vulcan mating period. It was marked by intense emotions and primal urges (known as plak tow, or "blood fever") that could kill the Vulcan if not satisfied. Physiological symptoms included elevated dopamine levels and fever. For such an orderly society of quiet sobriety, the madness which accompanied the outbreak of pon farr was an unavoidable evil. (ENT: "Bounty", "In a Mirror, Darkly"; TOS: "Amok Time"; VOY: "Blood Fever")
There are several diseases that the Vulcan species suffers from which include:
For an intensely logical race, the Vulcans did have spiritual beliefs. Though little is known about the details, their religious system was polytheistic. They also believed in the katra, the soul and consciousness of a person, which could be transferred psionically prior to death. (TAS: "Yesteryear"; Star Trek II: The Wrath of Khan; Star Trek III: The Search for Spock; TNG: "Gambit, Part I"; ENT: "The Forge", "Awakening")
Vulcans were generally non-violent, but logic dictated that combat was sometimes necessary. Vulcans could and did use weapons and practiced martial arts called tal-shaya and Suus Mahna. Most later Vulcans were vegetarians. (TOS: "Journey to Babel")
Vulcans were known for their high degree of honesty. They were extremely reluctant to tell a lie, and indeed it was said that "Vulcans could not lie". However, they would do so for what they perceived as logical reasons, though they rarely referred to their dishonesty as "lying." (TOS: "The Enterprise Incident"; Star Trek II: The Wrath of Khan; Star Trek VI: The Undiscovered Country) On at least one occasion, Spock lied without any apparent logical reason (and, in fact, for a reason apparently consisting of nothing more than humor), when he claimed to not have seen Kirk's last orders to himself and Doctor McCoy. (TOS: "The Tholian Web") However, this may, in fact, have been a result of those orders themselves, as Kirk had, in the orders, instructed Spock to follow McCoy's lead on intuitive and emotional matters, and McCoy had just refused to admit to seeing the orders.
Development of a Vulcan's life of logic began at a young age. Vulcan parents utilized learning tools, such as pleenoks, to train their infants in primary logic. (VOY: "Human Error") Vulcan children then learned to detach themselves from their emotions at an early age.
Despite this early training in logic, Vulcan children in nursery school were allowed to dance. These dances were reminiscent of the dances of the Orion slave girl, just not as well coordinated. (TOS: "Whom Gods Destroy")
As parents, Vulcans never shielded their children from the truth. Doing so only hindered their ability to cope with inevitable difficulties. A Vulcan parent's attachment to their children could not be described as an emotion. They were part of the parent's identity and the parent was incomplete without them. (VOY: "Innocence")
Vulcans sometimes had mates chosen for them by their parents at the age of seven. The mates were joined in a ceremony that linked them telepathically in a manner that was "less than a marriage, more than a betrothal". When the two came of age and underwent the pon farr, the link compelled them to follow through with full marital rituals, which cemented their relationship. (TOS: "Amok Time"; ENT: "Breaking the Ice")
If, for whatever reason, the female did not wish to go through with the marriage, then the ceremony of koon-ut-kal-if-fee ("marriage or challenge") was invoked. The male fought for the right to keep his mate against a challenger of her choosing. The female became the property of the male who won the contest, unless he chose to release her. The koon-ut-kal-if-fee was a fight to the death. (TOS: "Amok Time")
Contrary to stereotype, Vulcans did possess emotions; indeed, Vulcan emotions were far more intense, violent, and passionate than those of many other species, including even Humans. (TNG: "Sarek") It was this passionate, explosive emotionality that Vulcans blamed for the vicious cycle of wars which nearly devastated their planet. As such, they focused their mental energies on mastering them.
The essence of their logical society was in arriving at the truth through logical process. Emotions were illogical, thus making them impure, and deterrent to truth. Vulcans were born with the same emotions that afflicted their violent ancestors, but continual mental conditioning generally gave them the impassivity they sought. (TAS: "Yesteryear")
Though not all could arrive at the ultimate pure logical state, the exacting process of mental control gave Vulcans enough to conform to the ideals of Vulcan society. The ultimate level of logical thought was achieved through the attainment of kolinahr, which was said to purge them of all remaining emotions. (Star Trek: The Motion Picture)
Vulcans believed knowledge to be the best defense against unknown dangers, and pursued it with the intellect and logic that made them some of the finest scholars in the Federation.
Vulcans considered death to be the completion of a journey. Therefore, they did not fear it happening; however the loss of one's katra was to be avoided if possible, since the katra lived on beyond the physical death. (Star Trek III: The Search for Spock)
Although Vulcans were highly integrated into the Federation, in the 23rd century, some Vulcans viewed service in Starfleet to be less prestigious than attending the Vulcan Science Academy. (TOS: "Journey to Babel") Furthermore, among all the Federation members whose people served in Starfleet, Vulcans were the only ones to be accommodated with starships that had all-Vulcan crews, such as the USS Intrepid and the USS T'Kumbra. (TOS: "The Immunity Syndrome"; DS9: "Take Me Out to the Holosuite")
Culture and tradition
- Vulcans were fermenting wines, notably Vulcan port, during the 21st century. (DS9: "The Maquis, Part I")
- Although was not always so, most Vulcans were vegetarians. They also did not touch food with their hands unless wearing special gloves. (ENT: "Broken Bow", "Home")
- Guests in a Vulcan household were expected to rise before sunrise to prepare the morning meal. (ENT: "Home") Plomeek broth was considered a traditional Vulcan breakfast. (ENT: "Unexpected")
- Vulcans played a game known as kal-toh. (VOY: "The Omega Directive")
- What little is known about Vulcan religious beliefs indicates that beginning prior to the "Time of the Awakening" they were polytheistic. Surak's teachings became the primary focus of Vulcan spirituality/mysticism, but as late as the 23rd century it was still not unheard of to find Vulcans honoring the traditional gods. There are, however, no demons in Vulcan literature. (TAS: "Yesteryear"; TNG: "Gambit, Part I"; VOY: "Heroes and Demons")
- Many Vulcan females had names beginning with "T'P" (T'Pol, T'Pring, T'Pau, T'Pel, T'Pan), but not all (Valeris, Sakonna, Saavik, Selar); many males have names beginning with "S" (Spock, Sarek, Sybok, Surak, Stonn, Soval), again though there was variation (Tuvok, Lojal, Vorik, Taurik, Koss).
- Vulcan history
- Vulcan philosophy
- Vulcan language
- Vulcan salute
- Vulcan mating rituals
- Vulcan mythology
Science and technology
- "Broken Bow"
- "The Andorian Incident"
- "Breaking the Ice"
- "Shadows of P'Jem"
- "Fallen Hero"
- "Shockwave, Part II"
- "Carbon Creek"
- "Dead Stop"
- "The Seventh"
- "Cease Fire"
- "First Flight"
- "The Expanse"
- "The Forge"
- "In a Mirror, Darkly"
- "In a Mirror, Darkly, Part II"
- "Terra Prime"
- TOS films:
- "Encounter at Farpoint"
- "The Last Outpost"
- "Coming of Age"
- "The Outrageous Okona"
- "The Schizoid Man"
- "A Matter Of Honor"
- "The Dauphin"
- "Shades of Gray" (footage from "The Dauphin")
- "The Ensigns of Command"
- "Yesterday's Enterprise"
- "Captain's Holiday"
- "Ménage à Troi"
- "Ensign Ro"
- "Unification I"
- "Unification II"
- "The First Duty"
- "Imaginary Friend"
- "Gambit, Part I"
- "Gambit, Part II"
- "Lower Decks"
- "Preemptive Strike"
- TNG films:
- "The Nagus"
- "The Forsaken"
- "The Maquis, Part I"
- "The Maquis, Part II"
- "Through the Looking Glass"
- "The Visitor"
- "Bar Association"
- "Rules of Engagement"
- "Shattered Mirror"
- "For the Cause"
- "Broken Link"
- "Behind the Lines"
- "Favor the Bold"
- "Image in the Sand"
- "Take Me Out to the Holosuite"
- "Prodigal Daughter"
- "The Emperor's New Cloak"
- "Field of Fire"
- "Persistence of Vision" (illusion only)
- "Fair Trade"
- "Alter Ego"
- "Blood Fever"
- "Darkling" (hologram only)
- "Day of Honor"
- "Extreme Risk"
- "In the Flesh" (Species 8472 posing as Vulcan)
- "Bliss" (illusion only)
- "Body and Soul" (hologram only)
- "Flesh and Blood" (hologram only)
- "Renaissance Man"
^ The term "Vulcanian" has been described as an "Obsolete term meaning a native of the planet Vulcan. The term "Vulcan" has come to mean both the planet and the native of same." (Star Trek Concordance, p. 248) The origin of the term from a production standpoint dates to 1966, when NBC prepared a twelve-page booklet, entitled "Advance Information on 1966-67 Programming: Star Trek," which described the series' regular crewmembers. The description of Spock mentions that his father was a native of "Vulcanis," and his people were known as the "Vulcanians." (The Star Trek Compendium, p. 25) As a result of early "growing pains" in the writing staff, the term "Vulcanian" was used sporadically (and sometimes interchangeably) during the first season, where it was heard in "Mudd's Women", "Court Martial", "A Taste of Armageddon", "This Side of Paradise", and "Errand of Mercy". The Bajorans suffered similar "growing pains" when they were briefly known as the "Bajora" during their early appearances. The name "Vulcan" itself, in reference to the people, was first heard in "The Naked Time". See also: Vulcanian expedition and Vulcanian Scientific Legion of Honor.
In a story idea that the Star Trek: Deep Space Nine writers had that eventually became the two-parter "Homefront" and "Paradise Lost", the Vulcans were to withdraw from the Federation. The cause of this schism was to be their concern that the Federation was becoming too concerned of the Changeling infiltration at the cost of civil liberties. Starfleet was to assume incorrectly that the Founders had infiltrated Vulcan society. (Star Trek: Deep Space Nine Companion)
In the unproduced animated series Star Trek: Final Frontier, set in the far future, the Vulcans left the Federation at some point in the 25th century to discuss reunification with the Romulans.
For Star Trek Into Darkness, Vulcan ear prosthetics, in encapsulated silicone, were created by makeup artist David Snyder. A few changes were made to the Vulcan ears when compared to those from the previous film, Star Trek, on which Snyder had also worked. David LeRoy Anderson, the Makeup Department Head for Into Darkness, explained, "Our modifications were strictly mechanical, based on Dave's desire to make the application a little easier. Dave did a clay press of the existing sculpt and remodeled the ears to help mass-produce the pieces, and that gave us great edges." The ears were applied by Snyder, using a cotton swab, and (at least in the case of Zachary Quinto as Spock) a tiny amount of acetone. (Cinefex, No. 134, p. 77)
According to Star Fleet Medical Reference Manual (published in 1977 by "Star Fleet Productions, Inc."):
- Males height = 2.0 meters (6'6")
- Males weight = 70 kilograms (154.3 lbs)
- Females height = 1.7 meters (5'6")
- Females weight = 50 kilograms (110.2 lbs)
- Body temperature = 32.78°C (91°F)
- Heart rate = 242 bpm
- Blood pressure = 80/40
Vulcan blood vessels are more dilated than Humans. The larger blood vessels are the reason Vulcan blood pressure is lower. The dilated blood vessels and fast heart rate also play a key role in regulating Vulcan body temperature. A standard 91°F body temperature is maintained by the internal cooling mechanism of fast blood circulation. (Star Fleet Medical Reference Manual)
Vulcans do not have sweat glands, and cannot rely on evaporation as a means of cooling their bodies in the harsh heat of their planet's desert climate. Expelling heat through radiation is insufficient. Vulcans evolved an internal cooling mechanism. With an average body temperature of 91°F, the high blood flow circulates cool blood throughout their body. (Star Fleet Medical Reference Manual) This systematic means of cooling gives credence to McCoy's comment "that green ice water you call blood". (TOS: "The Paradise Syndrome")