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Trills / Dax


In my opinion, the Trills are one of the more fascinating aliens that Star Trek has ever invented, and in many ways the character of Dax is one of the more complex and interesting that we have seen. The purpose of this article is twofold - to discuss the Trills in general, and the interesting quandaries that they have presented us with, and to explore and summarise the history of the Dax character.

For those who don't know, the Trill are a "joined species". That is, they are composed of two very distinct races who have somehow managed to physically join themselves to one another and operate as a single being.

The Host

Trill were first seen in the TNG episode "The Host", where an Ambassador named Odan was attempting to negotiate a peace treaty between two political factions of an alien race. His father had negotiated a treaty between the same groups many years before, and it was felt that Odan might have influence because of this.

Odan had a built up forehead, something that is common to most aliens in Trek, but was otherwise essentially Human in appearance.

inline image

During the course of the episode it seemed that Odan had some form of illness - at one point a large swelling appeared on his stomach, and he used some kind of device to make it go down. Later he refused to go through a transporter, claiming that he found the idea of being disintegrated unpleasant much as McCoy had claimed a century or so earlier. When an emergency threatened, however, Odan claimed that using the transporter would kill him. Fortunately Riker is able to save the day without using a transporter.

Once the injured Odan was back aboard the Enterprise-D, Crusher scanned him and discovered what looked like a large parasite within him. She planned to remove it, but Odan prevented her - he declared that the parasite was actually a symbiont joined to the Humanoid host body, and that it was the symbiont which had the memories and personality. When Odan's body died Crusher lasered a cut in his chest and removed the symbiont, but it could not survive outside of a host for any length of time. A replacement host was still some time away, so Riker volunteered to host the symbiont until a new Trill host could reach them.

Once the host was implanted within Riker, his own personality was completely submerged by Odan. Although his metabolism was being damaged by the symbiont, Riker was able to maintain it until the new host arrived. This one was a female, who introduced herself to Crusher before the procedure. Once in place, Odan went on his way and the episode ended.

References made by Odan to the Trill as a "joined species" indicate that this joining is very much the norm, although this is somewhat speculative.

You have to wonder just what the hosts get out of this arrangement. These aren't animals, after all, they are thinking, sentient beings - the way that the replacement host greeted Crusher prior to the implantation proves that. Yet after joining the host's personality is completely submerged - it is the symbiont which does all the thinking, talking, moves the body around, etc. We don't know if the host's mind is blank during the joined life - if so, then joining is effectively death for the host. On the other hand, to still be aware of what was going on around you but to be unable to do or say anything about it would be a fate almost as bad as death. Perhaps worst of all is the possibility that the host is aware of its own existence but deprived of sensory input - this would make joining the ultimate in sensory deprivation for the host, who would surely go insane in short order.

Yet the hosts apparently volunteer for this life of living hell or worse - certainly Odan's final replacement showed no obvious signs of coercion. We can only speculate that there is some extremely heavy cultural push for hosts to offer themselves up to their captors.

Let's summarise the important points of the Trill as seen in "The Host" :

Deep Space Nine

Trills were next seen in Deep Space Nine, when Jadzia Dax arrived as one of the main characters. The first and most obvious change from TNG was in appearance; Jadzia had none of the built up forehead that Odan had possessed, but she did have some skin markings; a series of spots which went from her forehead down the side of her face and down her neck. Jadzia once famously confirmed that the spots go "all the way down"... We've since seen this pattern repeated on all Trill.

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The first episode also established another fact about Jadzia, virtually in the opening dialogue :

Sisko : "He's a little young for you, isn't he?"
Jadzia : "He's twenty seven, I'm twenty eight."
Sisko : "Three hundred twenty eight, maybe. Did you tell him about that slug inside you?"
Jadzia : "Yes Benjamin, he knows I'm a Trill. He finds it fascinating, he's never met a joined species before"

This confirms that the Trill still have a Humanoid host and wormlike symbiont, and gives us an age range for symbionts - Jadzia's is some three hundred years old.

One of the early DS9 episodes, "Dax", focuses almost entirely on the question of Trill identity. An alien named Ilon Tandro attempts to remove Dax from the station so that she can be tried for crimes supposedly committed by Curzon Dax, the previous host of the Dax symbiont. Sisko argues that Jadzia Dax cannot be held accountable for Curzon Dax's actions because each time a symbiont is moved to a new host, the personalities of both host and symbiont blend to create a new person. This is distinctly different from the type of joining presented in "The Host".

Throughout Deep Space Nine Jadzia uses the transporter frequently, and without any apparent health problems. Again, this is different to the TNG version in which Trill could not be transported.

We see symbionts being transferred between hosts several times during DS9. The first occurs in an Orb-induced flashback Jadzia experiences during "Emissary". She sees the operation in which the Dax symbiont was transferred from Curzon to herself. There is no cutting involved - rather, the trill is removed from a pouch-like aperture in the stomach. It's possible that Jadzia was not imagining an accurate scene here, since these "Orb experiences" are known for presenting things somewhat other than accurately.

However, we see an actual transfer in the episode " Invasive Procedures", and again Jadzia seems to have some kind of stomach pouch. This is another change from "The Host", in which Odan's stomach had to be cut open with a laser.

Another idea which crops up in several DS9 episodes is the fact that most Trill are not actually joined at all; the episode "Equilibrium" we learn that only one in one thousand Trill are joined. This is widely claimed to be because few Hosts are compatible with the joining process, but in fact this is a lie told by the government and in truth nearly half of all Trill are compatible. The one in a thousand lie is told because the government feared that if the truth were known, symbionts would become highly sought after commodities to be bought and sold.

For comparison with our earlier summary, then :


I can see only three ways to approach the Trill problem :

Option 1 : More than one Trill species

First, we could assume that there are two species called the Trill, and that both just happen to be joined species. Perhaps one is called the "Tryl" and the others are called "Trill". On the plus side this would completely explain all of all the differences between the two versions of the Trill. On the minus side - two species, with identical-sounding names, who just happen to both comprise humanoid hosts that join to slug-like symbionts? You have to believe some wacky stuff to be really into Star Trek, but that pushes credibility a little far for me!

Option 2 : More than one race

Secondly, we could assume that there are two (or more) distinct races of Trill host. If you put a Trill from TNG next to a Trill from DS9 they do look somewhat different, but not really much more so than an Asian Human and a Caucasian Human. And Humans are not all that varied compared to some species - consider a Chihuahua next to a St. Bernard!

For convenience, I will call the Trill as seen in TNG "Alphas" and those seen in DS9 "Betas". The differences are then explained as being peculiarities of the two races.

So we can say that transporters are fatal to the Alpha hosts, but not to the Betas or the symbionts. We could even say that the problem was unique to Odan - we saw in TNG's "The Schizoid Man" that using the transporter causes a degree of shock to the body's systems and that very ill people cannot use it because of this reason. It's not at all clear if Odan's inability to use it was intended to be a general peculiarity of the Trill species, or if Odan himself was sick enough that he personally could not use it. Either way this explanation can explain away the problem.

We can also assume that the pouch is a peculiarity to the Alpha hosts, and that the joining process is somewhat different - the Alphas apparently have weak minds, or some chemical difference in the brain or something, which means that their personality is submerged by the symbionts. The Betas, on the other hand, seem to suffer from no such problems.

The apparent difference in the number of Trill joined cannot really be explained by this theory. We just have to assume that the joined Trill are regard as such a vital aspect of Trill culture that the whole species calls itself joined even though the vast majority are not.

If we do go with this option, we need to explain why so few of the Alpha hosts are ever seen. I would suggest that they make up a very small percentage of the population - 10% or less.

Option 3 : It's just a TV show, stupid!

Of course there is the old fallback position - mistakes are just that, and anybody who has the time and effort to spare to put a lot of thought into this kind of thing really needs to go out and get a life. I mean, if we aren't careful people will go creating huge websites about this kind of stuff, and where would it all end? I tend towards Option 2, and that is the assumption I went with whilst writing the Trill species entry on this site.

Jadzia Dax

So much for the species; let's talk about Jadzia!

Jadzia has had eleven joinings with ten distinct hosts for periods ranging from decades to hours. In the episode "Facets" Jadzia carries out a procedure that transfers the personality of each past host into one of her friends so that she can talk to them and learn more about them. It's an excellent source of information on the past life of Dax, the kind of episode we overly-fanatical types love! In order, then :

LelaA gentle, somewhat motherly type, Lela was a politician.
TobinVery shy and introverted, Tobin was a genius mathematician who created a very clever proof of Fermat's last theorem. Much of Jadzia's scientific knowledge comes from Tobin.
EmonyEmony was a gymnast. She would often stand on her head to help her think. Emony once met and had sex with Doctor McCoy, some time before he became a doctor.
AudridAudrid we don't know much about.
ToriasTorias was a test pilot. Daring and brave, he was killed in a shuttle accident only six months after being joined.
JoranJoran was joined after Torias, but proved to be mentally unstable and murdered at least one person. The symbiont was removed and the memories of the ordeal suppressed by the Symbiosis commission to cover up knowledge of how easy it is to join a symbiont to an unsuitable host.
CurzonCurzon was a diplomat who appears to have mostly dealt with Klingons. He was something of a mentor to Ben Sisko, and was renowned as a hell raiser.
JadziaJadzia was, obviously, the character we saw through most of DS9. Beautiful, fearless and intelligent - what a combination!
VeradVerad stole the Dax symbiont from Jadzia in "Invasive Procedures" and implanted it within himself. Sisko was able to recapture Verad within a few hours.
JadziaNaturally, after Verad was captured Jadzia regained the symbiont. She retained all of Verad's memories afterwards. Jadzia was killed by Dukat in "Tears of the Prophets".
EzriAfter Jadzia's death, the symbiont itself was on the way back to Trill when medical problems meant that it had to be implanted immediately. Ezri was the only available host, and so had to take the symbiont completely unprepared. It was a rather daunting experience for her.

We have some fairly good dates regarding the Dax hosts, but there is also some total conjecture. We know from "Emissary" that Dax was roughly 328 years old, though Sisko was apparently being somewhat approximate there. In the season 6 episode "You Are Cordially Invited", we get a more solid age for Dax when Sisko claims that she is "three hundred fifty six years old".

We don't actually know for certain what this age refers to - is the "birth year" the year the symbiont was born, the year of the first joining, or some other year altogether? But we can make a good guess, as you will see later.

I'll work backward through the hosts, since dates tend to get more questionable as we go further back. The last host is the simplest, and most concrete - we know for certain that Ezri was joined in the break between Deep Space Nine seasons six and seven, which means it happened right around the end of 2374 or the very beginning of 2375. She was still joined at the end of 2375, when the series ended.

Jadzia's second joining with the symbiont occurred in the episode "Invasive Procedures", after it was recovered from Verad. The episode was set in season 2, i.e. 2370. She remained joined until the pagh-wraith possessed Dukat killed her on Deep Space Nine in late 2374, leading to Ezri's joining shortly afterwards.

As mentioned, Verad stole the symbiont from Dax in "Invasive procedures". He only possessed it for a matter of hours before Sisko recaptured him and Bashir returned the symbiont to its rightful owner, Jadzia.

Jadzia's first joining happened very shortly before the pilot episode of Deep Space Nine - Ben Sisko was still trying to get used to seeing his old friend Curzon in a female body when she first came aboard during "The Emissary". The episode "Equilibrium" gives a more solid timeframe :

Sisko : "It's funny... it's been almost four years since Curzon died, and I still miss the old man."

This is a season 3 episode which takes place in 2371, so Curzon died sometime around 2367 and 2368. Since season one of Seep Space Nine takes place in 2369, the date of 2368 looks pretty concrete for Curzon's death.

Jadzia's joining occurred whilst Curzon was still alive according to her Orb experience, so if this image was accurate then her joining would have happened in the same year of 2368 , after about eighty five years of joining. This means that most of his hell raising with Ben Sisko occurred whilst he was well into his seventies or more!

The timeline for Curzon's immediate predecessors, is very tight. Originally Jadzia believed that the Dax symbiont had passed from straight from Torias to Curzon, but in the episode "Equilibrium" Sisko discovers that something more sinister happened. He gives us a specific date when confronting Dr. Renhol :

Renhol : "Commander I don't know what you're talking about."
Sisko : "I'm talking about the fact that eighty six years ago the symbiosis commission mistakenly gave the Dax symbiont to Joran Belar."

Sisko and Bashir go on to reveal that Joran was a violent psychopath who had rejected the Dax symbiont :

Bashir : "According to our information, he was joined to the Dax symbiont for six months."

So, since the episode is set in 2371 we know that the Joran host was joined in 2285. The rejection and following transfer to Curzon must have followed in either 2285 or 2286. Curzon was therefore joined for a total of eighty three years.

Before Joran, the host was Torias. This joining was a short one - according to "Rejoined" Torias was only joined for about six months before the shuttle accident which killed him. So Torias would have been joined in 2284, six months before the joining to Joran.

Assuming that no great time passes between the death of one host and the succession of another, Audrid would have died in 2284. In "Babel" Dax said she had not been female for some eighty years. Since Audrid was the last female host, this would give a date of 2289 for Audrid's death. This is contradicted by both "Equilibrium" and "Rejoined". In addition, "Blood Oath" establishes that Curzon Dax was already an important Federation diplomat in 2289, which is unlikely if he had only just been joined. It therefore seems that the "eighty years" figure is somewhat rounded, and the bulk of the evidence points to the 2284 date.

As far as Emony is concerned, we have only one certain date - in "Trials and Tribble-ations" Jadzia says that Emony met Doctor McCoy whilst he was young. She said that she had thought at the time that he would become a Doctor as he "had the hands of a surgeon". This implies that he was not actually a Doctor at the time, nor even in medical school. We know from "Encounter at Farpoint" that McCoy was 137 years old in 2364, giving him a birth date of 2227. Presuming he entered medical school at age 18 in 2245, Emony must have met him sometime around 2244.

Given that Emony was carrying a symbiont when she met McCoy, she is unlikely to have been much younger than 20 or so. And since the two slept together, she was unlikely to be greatly older than him - there's no real limit, but fifteen years or so would probably be a sensible maximum. This means that Emony would have been joined sometime between 2230 and 2244, probably tending towards the latter date.

If we assume that Emony was joined in 2230, then the first two hosts, Lela and Tobin, between them have to cover the period from 2018 through 2230 - about 106 joined years each.

This seems excessive, bearing in mind that Curzon only lasted about 85 years after being joined. We could assume that Curzon's hard living led to premature ageing and death, but this seems unlikely and in any case it isn't really necessary. We have seen that symbionts live in underground liquid pools without any host, so we can push forward the date of the joining to Lela by assuming that the symbionts live for some decades in these pools before their first joining. If we put the first joining at 2060, then Lela and Tobin would have 85 joined years each.

So we have :

DaxThe symbiont was born in 2018. This would assume that Sisko's statement that Dax was 356 in 2374.
LelaJoining date uncertain - possibly around 2060. Death date uncertain, possibly around 2145.
TobinJoining date uncertain, possibly around 2145. Death date uncertain, but probably around 2230 - 2244.
EmonyWas, err, 'compatible' with teenaged McCoy around 2245. Probably joined sometime around 2230 - 2244. Death date uncertain, but sometime between 2245 and 2284.
AudridJoining date is uncertain, but between 2245 and 2284. Died 2284.
ToriasJoined 2284, died after six months in 2284 or 2285.
JoranJoined 2284 or 2285, stayed joined for about six months before being removed in 2285.
CurzonJoined in 2285, died in 2367.
JadziaJoined 2367; unjoined briefly in 2370 before being returned.
VeradJoined in 2370, for just a few hours.
JadziaAfter being rejoined in 2370, remained with the symbiont until her death in 2374.
EzriJoined 2374, remained joined at the series end in 2375.

So there we have it, a somewhat complete and moderately accurate timeline for the life of one of Deep Space Nine's more convoluted characters!

Colour key

Canon source Backstage source Novel source DITL speculation

© Graham & Ian Kennedy Page views : 61,817 Last updated : 16 Jan 2021