The Evolution of Klingon Foreheads
by Bernd Schneider and Jörg Hillebrand
TOS Klingons are often said to look just like humans, only with beards and thick brown make-up. Actually it seems to be correct that the TOS Klingons who were clearly visible were all played by white actors. But looking at Kras, Krell, Kor, Koloth, Kang and the others (see below for more examples), only half of them seem to wear dark make-up like Krell, Kang and most of Kang's crew. It is also noteworthy that most Klingons are racially indifferent, while some others like Kor and the commander in "Elaan of Troyius" were given a distinct Asian appearance.
Kang, Koloth, Kor
The three Klingons who had appeared in TOS were all given ridged foreheads when they returned in DS9: "Blood Oath", played by the same actors Michael Ansara, William Campbell and John Colicos, respectively. So at some point between 2268 and 2371 they must have undergone a surgery or genetic therapy to restore their foreheads.
Kor appeared again in DS9: "The Sword of Kahless" and "Once More Unto the Breach", with largely the same make-up as in "Blood Oath".
We have never seen the actual historical Kahless. But we may take for granted that the representation of Kahless created by the Excalbians in TOS: "The Savage Curtain" and the Kahless clone from TNG: "Rightful Heir" are supposed to be the very same person. It is striking that not only the TOS Kahless has lost his forehead crest, his skin is also much darker than that of his TNG counterpart, exceptionally dark by TOS standards. On the other hand, both may be explained with crude records the Excalbians may have drawn from the Enterprise database about the Klingons. The picture of Kahless at the Boreth Monastery shows him with ridges, anticipating the look of the Klingons that would be established for the 22nd century in Enterprise. The same goes for the Kahless shrine and Worf's statue of Kahless and Morath that can be seen in a number of TNG episodes.
It is remarkable that the forehead of the cloned TNG Kahless is jagged like hardly any other, especially if we consider that the clone was created to be not very old (young enough to lead the Empire). Moreover Kortar, another Klingon mythological figure, sports a very similar forehead as Kahless. We may understand this as a sign that, irrespective of the ultimate solution shown in ENT: "Divergence", the average height of the ridges has already decreased since the ancient times of Kahless.
It is noteworthy that all of the first ridged Klingons who briefly appeared in "Star Trek: The Motion Picture" had very narrow and tall ridges with some sort of a spine structure, like the battlecruiser commander played by Mark Lenard. In the later movies the foreheads were conceded more variety. "Star Trek V" and even more obviously "Star Trek VI" are special cases because here the foreheads must have been more or less deliberately toned down.
"Star Trek VI" Klingons
While there are make-up variations between all of the TOS movies, several Klingons in "Star Trek: The Undiscovered Country" stand out because they have comparably low ridges. The actual reason was that some actors like Christopher Plummer (Chang) did not want to wear thick make-up. In the light of the new development in "Affliction" and "Divergence" these Klingons could be the missing link. Curiously Colonel Worf, who defended Kirk and McCoy on the trial, had one of the least pronounced foreheads of all. He is quite obviously supposed to be Worf's grandfather or great-grandfather. So Worf may have a personal motive to remain silent about the Klingon metamorphosis, knowing that his own family was affected too.
It can be noticed that, like already in the movies "Star Trek III" and "Star Trek IV", there is some variety of Klingon forehead patterns in TNG, and all of them are quite pronounced. Some foreheads seem to reappear, which may have to do with masks being re-used. Only very few Klingons really stand out like K'mpec with his very unusual pattern.
The make-up of Klingons in TNG, DS9, Voyager and Enterprise remains consistent in its basic pattern and the range of variations (even though we may have expected to see TOS Klingons at the beginning of ENT).
The very first Klingon woman (and one of only two in all of TOS) was Mara in TOS: "Day of the Dove". Her look complies with that of the Klingon men of the time. The actress is wearing dark make-up like at least some of the men and like her husband Kang. Only her eye make-up that is clearly not meant to be a natural adornment is remarkable in retrospect. We certainly would not expect "modern" Klingon women to wear such a make-up. Valkris from "Star Trek: The Search for Spock" has comparably slight ridges, as has Vixis from "Star Trek: The Final Frontier". The ridges of Azetbur from "Star Trek: The Undiscovered Country" are not even recognizable from a distance. Her father Gorkon has a more pronounced crest, which may have to do with his age, but also with the fact that women generally have subtler ridges. This subtlety is what all Klingon women have in common so far.
In TNG, DS9 and Voyager, on the other hand, a clear trend is established to have Klingon women who have tall ridges just like the men. The sisters Lursa and B'etor are the most noticeable examples for this new "ugliness". Their ridges are also similar to those of their brother Duras and nephew Toral (below).
One Klingon woman that Riker, with Q's powers, created for Worf in TNG: "Hide and Q", is remarkable because her forehead crest is partially covered by hair. Although it is a standard Klingon forehead appliance, she looks a bit like a Kobliad or a Karemma. In the holodeck simulation of TNG: "Future Imperfect" there is one extra with what looks like a rather cheap Klingon mask with a large ridge. From the dialogue we can safely conclude that she is meant to be Klingon, and the costumer's notes for the episode confirm that.
K'Ehleyr looks much like we would imagine a half human, half Klingon woman. She has an overall smoother forehead than full Klingon women of the TNG era, yet considerably more pronounced than the full Klingon women from the TOS Movie era. Quite contrary to K'Ehleyr, like Worf we wouldn't notice that Ba'el from TNG: "Birthright" was half Romulan until we saw her pointed ears. Her forehead ridges are very pronounced. The central ridge has an unusual spine pattern like that of her (fully Klingon) mother Gi'ral. Yet, the lateral bones are much less protruding on Ba'el's head. Moreover, Ba'el has a smaller crest forming a "V" which is at least remotely reminiscent of the Romulan look. Klingon-human hybrids over several generations, of which all must be descendants of Worf, could be seen in DS9: "Children of Time". Owing to the dilution of their Klingon genes these people have only slightly protruding bones and single spikes (a bit like Naomi Wildman) instead of a ridge.
The most prominent Klingon-human hybrid is B'Elanna Torres. Her ridges are lower than those of K'Ehleyr. A curiosity is the full-Klingon B'Elanna that appeared in VOY: "Faces". Her look complies with the look of other Klingon women since TNG, justifying why the mixed-race character B'Elanna was given very fine ridges. B'Elanna's mother Miral is obviously wearing the same full-Klingon make-up in VOY: "Barge of the Dead". It is no surprise that in VOY: "Endgame" Miral Paris (after it was revealed that she as a quarter-Klingon would still have many Klingon features in VOY: "Lineage") has essentially the same ridges as her mother B'Elanna. They may be somewhat subtler on Miral though.
Worf's forehead ridges changed throughout the seven seasons of TNG. The lateral bones of his forehead prosthetics were raised, and the wrinkles were toned down. Most visibly the transversal rib-like wrinkles were flattened out for the second season. Later on in the series the previously rather thin central ridge was widened and modified to exhibit more peaks and wrinkles. The changes are overall slight enough to be interpreted as a part of Worf's natural aging process. The make-up was not returned to the initial version of the first season for the flashbacks in TNG: "All Good Things" though.
It is also worth mentioning that Worf's ancestor from "Star Trek: The Undiscovered Country" has essentially the same structure of the forehead bones, only much smoother. This is only one more sign that we are looking at a transitional state of the Klingon look.
Alexander grows up very quickly, at least by human standards. He seems to have inherited the ridges mainly from his father Worf. We first see Alexander in TNG: "Reunion". For later appearances the make-up may have been revised very slightly. It is possible that the edges were sharpened. In DS9: "The Way of the Warrior" there is a photo of Worf with Alexander, but this is probably just a photomanipulation. Alexander, now almost grown up, reappears in DS9: "Sons and Daughters" with basically the already established look. Considering that Alexander was played by no less than four different actors, the subtle changes to his forehead are of minor significance anyway. Finally, we can see an adult Alexander from the future in TNG: "Firstborn", disguised as K'mtar. This Alexander has Worf's characteristic crest once again.
The Duras family
Duras's forehead is quite distinctive because of the structured bulge around the central ridge. His sisters B'etor and Lursa (see above) sport the same look. Toral inherited the bulge too. He first appeared in TNG: "Redemption" where Worf spared his life. Here Toral's forehead ridges are similar to those of his aunts and his father, with pronounced lateral bones, but not quite as jagged. When we see him again in DS9: "The Sword of Kahless", his central ridge seems to have grown in the few years since the TNG episode. He is played by a different actor too (TNG: J.D. Cullum, DS9: Rick Pasqualone). Actually, Toral's look in the DS9 episode is practically the same as his father's. It is not surprising that the 22nd century Duras, Son of Toral (so it's just too obvious that he must be an ancestor) has the very same appearance. Note the shape that looks like an inverted heart above the eyebrows of all three Klingons. They are identical, a sign that the mask has been re-used without changes.
DS9: "Trials and Tribble-ations"
The look of Arne Darvin is as consistent as it can be, considering that the actor Charlie Brill is the same in DS9: "Trials and Tribble-ations" as already in TOS: "The Trouble with Tribbles". All other Klingons that appear in the DS9 episode are of the smooth type too. The shots comprising Kang, Korax and the others were inserted without changing anything about their appearance. Moreover, new Klingons with smooth foreheads were filmed for scenes in the bar.
ENT: "Divergence" and "Affliction"
For the first time since TOS (with the exception of the newly created Klingons in DS9: "Trials and Tribble-ations") we can see Klingons with flat foreheads. Their look is consistent with TOS. Moreover, Antaak, who made the transformation from smooth to ridged in just one episode, is living proof for the theory that Kang, Koloth and Kor have undergone the reverse procedure.
Ancient and mythical Klingons
Here are some depictions of ancient Klingons besides Kahless and Kortar. The monster to which Worf mutated doesn't have to be closely related to the Klingon species considering that Barclay was turned into a spider by the same retrovirus. Likewise, Fek'lhr (Ardra who created the holographic image must have taken it from a commonly available database) is not necessarily a scientifically correct representation of early Klingons, but may be just a mythological figure. The same could apply to the Klingon appearance of "God" in "Star Trek V", although this one looks much like a "normal" Klingon. The statues in the Hall of Warriors look like modern Klingons too. They don't have to be very old though, and we would be rather surprised anyway if we saw any Klingons with flat foreheads (representing an era that Klingons remain silent about).
Klingons were originally meant to appear in "Star Trek (2009)" (they were holding Nero prisoner on Rura Penthe), but the footage was cut from the movie. All Klingons in this footage are wearing helmets with a ribbed pattern similar to the forehead ridges of 22nd or 24th century Klingons. This does not mean that they necessarily have those ridges underneath the helmets. The helmets could just as well have been designed to be reminiscent of the lost forehead ridges. Anyway, the same helmets appear on screen in "Star Trek Into Darkness". One Klingon eventually takes off his helmet, revealing his forehead ridges with a unique pattern. This one Klingon may be an exception, but there wasn't a single exception among dozens of Klingons we could see in TOS.
Classic Klingons in new Trek
Star Trek Picard so far avoided the topic of how Klingons should look like, except for the use of stock footage, in which Worf was not subjected to a Discovery-style reboot.
Lower Decks, on the other hand, frequently shows Klingons, and exclusively the authentic TMP-style make-up.
On a final note, there is so much variation in the look of the Klingons that it may be possible to mistake them for a different humanoid race (or mistake another race for Klingons) if we were to assess only the looks of their foreheads. The Akritirians from the Delta Quadrant, for instance, look a lot like several of the Klingon variations shown on this page. In this light the Klingon Forehead Problem is further alleviated. It only appears to be grave because the Klingons are a frequently recurring race.
Another point of interest is that all members of a Klingon family share a common ridge pattern. This pattern even remains the same over a number of generations (Duras), and it seems to have survived the mutation too (Worf). Although unintentional, these subtle hints support the obvious explanation for the forehead mutation in the Enterprise episodes "Affliction" and "Divergence".
The existence of a variety of Klingon forehead patterns could be attributed to sexual selection. If similar foreheads are a sign of relatedness, then Klingons may be predisposed to sexual attraction to different patterns, just like human teenagers seek sexual contacts that are preferably not like their brother or sister. So it may boil down to a matter of incest avoidance.
Thanks to Matt Rudawsky for spotting some mislabeled pics, to Barryg for the note about forehead variety being a natural means of incest avoidance and to Colin W. Warde for a note about the Klingon woman in "Future Imperfect".