As the title suggests what is the nature of the Vulcan Romulan divide?

Is it biological, are the Romulans biologically distinct enough to be considered a different species ?

For example would a medic treating injuries in war time need to check if the patient was from Romulus or Vulcan in order to provide adequate care ?

Or is it political with the only thing separating them is their differing philosophies ?


Initially a political issue which drove the two groups apart (whether to adopt the teachings of Surak, based in logic and reason) or to continue the more warlike nature of the Vulcan species. Those who rejected Surak would leave their world and become the Romulans.

  • When Surak's reforms of embracing logical principles and rejecting emotions spread rapidly across Vulcan in the 4th century, a minority rejected Surak's ideals. Those who marched beneath the banner of the raptor, which became the symbol of the Romulan Star Empire, departed Vulcan in the 4th century.

  • Later, some of their descendants established settlements on the planets Calder II, Dessica II, Draken IV, Yadalla Prime, and Barradas III. An ancient offshoot civilization, called the Debrune, at one time existed on Barradas III, but it had died out by the 24th century. (ENT: "Kir'Shara"; TNG: "Gambit, Part I")

  • Being Romulan is as much a political identity as a physiological identity. The Romulans also lack the rigid mental disciplines common to their Vulcan cousins. These mental conditionings can affect the Vulcan physiology, particularly their brains in a number of ways.

  • 2,000+ years of differentiation between the two groups, as well as living on different planets and exposure to different ecosystems has lead to the two groups having similar overall biological capacities but distinctions due to their time apart.

  • Both groups are still able to reproduce with each other without technological support.

  • Yes, there are some differences between the two groups that would require a medic to take their species variation into consideration when treating them. A lack of knowledge about the Vulcan healing trance for example might be dangerous to a medic skilled in Romulan physiology but lacking in training for Vulcan physiology.

  • 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")

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    This is non-canon, but according to Vulcan's Soul, Remans are also descended from Vulcans. They were telepathic Vulcans who refused to give up their abilities and were enslaved by the non-telepathic Romulans. This is consistent with canonical portrayal of Romulans never using any telepathic abilities while the Remans do. Additionally, the original timeline doesn't show Romulans as being significantly stronger than Humans, so that's another physiological difference. – Lèse majesté Aug 26 '13 at 1:58
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    "Both groups are still able to reproduce with each other" isn't a particularly strong statement in the Star Trek universe, where we know Cardassans have reproduced with Bajorans -- and humans with Klingons and Betazoids and Romulans and others. – Plutor Aug 26 '13 at 12:32
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    Without technological support. Most hybridization requires some level of genetic or technological support to be effective. The Romulans and Vulcans are so closely related no such technology is needed. – Thaddeus Howze Aug 26 '13 at 16:06
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    The Cardassian/Bajoran hybrid we know of (Ziyal) had no technological support (since she was unintentional). Most of the rest are unclear at best. – Plutor Aug 26 '13 at 16:31
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    That we know of. I don't ever remember them talking about how or why Ziyal managed to be born considering the vast differences between the Cardassian and Bajoran genome. Unless there is more genetic compatibility between the two groups than we are told about... – Thaddeus Howze Aug 26 '13 at 17:03

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