Who are the Trill in ‘Star Trek?’

Space, the final frontier, is unsurprisingly filled with a tons of alien species in the world of Star Trek. From newly introduced species like the Lanthanites to the fluffiest of trouble-making Tribbles, the expansive arrays of cultures found in space set the stage for the amazing stories told throughout the series.

The Trill can be counted among the more complex and confusing of those species, especially because the word “Trill” itself can refer to several different things in the universe. So it’s time to simplify the Trill once and for all so everyone can understand who and what they are.

Trill: Star Trek‘s humanoid species

On the planet Trill — because that won’t make things even more confusing — live a humanoid species called Trill. They are distinct from humans due to the stripes of small brown spots that span from their foreheads all the way down to their toes on either side of their bodies.

However, the spots aren’t the only major difference from humans. Trills as a species were the only humanoids capable of hosting the Trill symbiont which also lives on their planet without it resulting in their death for many years. These two species did not interact until a major environmental event forced the two to join so that they could survive.

Not all Trill are compatible with taking on the Trill symbiont and there is a long selection process among those even capable of deciding who is given the honor of doing so. Once combined with a Trill symbiont, having it removed will result in the quick deterioration and death for the Trill in question. Combining with the Trill symbiont allows the two to share their memories while having two distinct brainwaves. It is considered a high honor among the species to take on a Trill symbiont.

The Trill symbiont

The Trill symbiont (and yes, that is the correct word, not symbiote), also live on the planet Trill within the Caves of Mak’ala. They live in milky water within the caves where they communicate through electrical impulses within the water. This is where they presumably live and make baby symbionts before eventually joining with their humanoid hosts.

Unlike the Trill that host them, the Trill symbiont can live for hundreds of years. This allows it to keep memories from multiple past lives and have a vast array of achievements over time. This also allows the symbiont to experience life as different genders as the body of the Trill who is their host is not always the same gender as the previous host.

Can a human host a Trill symbiont?

In the episode “Forget Me Not” in Star Trek: Discovery, a new procedure has been created to safely combine humans with a Trill symbiont so as not to result in death, as would happen previously. This isn’t something done often, however, and is extremely disapproved of by the Trill, even to the point of violent reactions. Especially with how few Trill get to combine with Trill symbionts in the first place, it is understandable there may be a lot of jealousy that a human could get the honor instead.