Vulcan

Physiology

The Vulcans (rare: "Vulcanians") were a humanoidspecies widely known for their logical minds and stoic culture. Hailing from the planet Vulcan, the Vulcans were instrumentally responsible for the founding of the United Federation of Planets.

Genetically, Vulcans and Humans were similar enough that they could produce offspring without any problems.

Externally, Vulcans were generally similar to Humans, the chief exceptions being the Vulcans' notably arched and upswept 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 ofEuropean 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 ofEast Asian descent. However, most Vulcans had a vaguely Eurasian appearance.

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.

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 be chemically capped, as Human teeth may be since the 20th century, in order to prevent decay.

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, and beat several hundred times per minute. They also had no appendix.

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.

Vulcan body chemistry used little, if any, sodium chloride compared to that of Humans.

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. 

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.

Vulcan hearing was very sensitive. Vulcan females possessed a heightened sense of smell.

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. 

Vulcans had a superior metabolism to Humans. Caffeine and sapotoxins had little effect on them. They were also capable of surviving for long durations without food or sleep. Under stress, Vulcans could do without sleep for weeks. Tuvok once claimed that as a Vulcan he was capable of going without sleep for two weeks, although shortly after making this claim he was observed to fall asleep in the command chair after having gone a little over 10 days without sleep.

Vulcans were on average three times physically stronger than Humans, and had considerably faster reflexes. 

Vulcans were very sensitive to nitrous oxide gas, which rapidly rendered them unconscious.

Vulcans typically had a lifespan of two hundred years or more.

Illness and Diseases known to species:

Bendii syndrome
Illness which sometimes affects Vulcans over the age of 200. It causes a total loss of emotional control, which can be telepathically projected onto others.

Neurochemical imbalance
Neurochemical Imbalance26 A serious condition which arises in Vulcans during Pon Farr.

Pa'nar syndrome
Vulcan disease spread through mind melds. It was very similar to thymic sclerosis. It was incurable in 2152 and caused degradation of the synaptic pathways and affected the endocrine and immune systems.

T'lokan schism
The breakdown of mental synapses in Vulcans caused by surfacing of repressed memories.

Thymic sclerosis
A nonfatal Denobulan illness whose pathology is quite similar to Vulcan Pa'nar syndrome.

Tuvan syndrome
A disease which affects both Romulans and Vulcans.