Star Trek: 10 Things We Now Know About The Breen

Even in the 32nd century, there can't be much, if anything, under 'Breen' in Doctor McCoy's revised… revised, revised, revised… 'Comparative Alien Physiology' textbook. After all, Captain Michael Burnham was surprised to learn L'ak's origins, and no one else in Starfleet (or otherwise) had pointed out that he was a Breen earlier!

What we do know about Breen biology from the 24th century is patchy at best. From Data's "not empathically detectable," we found out from Doctor Bashir (the real one, not the changeling one) in In Purgatory's Shadow that the Breen (or, at least, "that Breen" in the prison barracks) had "no blood".

In the 32nd, when impaled in Mirrors, L'ak did appear to bleed, however. If that's the case, perhaps the Breen only do that when they are in solid form? To exist in that solid state seems almost shameful for a Breen, and presumably they have to remove their helmet/suit first? Furthermore, Burnham's "blood bounty" might simply have been a loose translation or turn-of-phrase. 

However, in Erigah, as L'ak takes a turn for the worse, the medic working with Doctor Culber says, "O2 saturation levels are still dropping." In humans, anyway, that requires blood. At one point in the episode, Primarch Ruhn does also clearly state that, "The only payment for a blood bounty is blood." 

More generally in Erigah, we got to learn quite a bit more, and yet at the same time cryptically little, about Breen physiology. Culber admitted the Federation's ignorance on the matter as much. We do now know that Breen metabolism is reactive to tricordrazine! More hopped up than McCoy hopping through the Guardian of Forever, L'ak eventually succumbed to an 'accidental' massive overdose of the stuff.

One of the most enduring points about Breen biology is their apparent need for 'refrigeration suits'. As mentioned earlier, Ira Steven Behr's original rationale for the species was that they wore costumes because they lived in the cold. "If anyone knows how to keep things cold, it's the Breen," Captain Sisko would then say in For the Uniform. That relative certainty was upended, however, by one little Vorta in The Changing Face of Evil:

Weyoun: I'm sure you've read the intelligence reports that say that their homeworld is a frozen wasteland. Well, it's not. The climate on their planet is quite comfortable.

Damar: Then why do they wear refrigeration suits?

Weyoun: They won't say. […] They're full of surprises.

That, they most definitely are! From Erigah, we have gotten the beginnings of an answer to the Breen's cold conundrum. In it, Doctor Culber, having done a "deep dive into Dominion War era medical research," discovered "some evidence that the Breen are capable of somatic cell regeneration in extreme cold." Culber also located a "Breen refrigeration unit" in storage, thus confirming the Breen do use refrigeration units, and planned to use it to convert one of the biobeds into a "low temperature ICU unit." 

Technically, all that allows for both Sisko and Weyoun to be correct (*shudder*) — the Breen don't have to be cold, but they can benefit greatly from the cold. Indeed, before the tricordrazine, L'ak's condition began to improve thanks to the chilly treatment. In Culber's words, "Sub-zero gasses promote a strong immune response unique to the Breen." That, in part, resolves that. But, whatever the purpose of the "vital [and damaged] organ" that appeared on Culber's scan of L'ak's chest in Erigah — seen again during the Breen medic's intervention — is anyone's guess!