The Jaridians are large and muscular beings with a vaguely reptilian appearance. Unlike the androgynous Taelons with whom they share a biological ancestor, the Jaridians have two sexes, with both males and females engaging in combat.
Though not frequently seen on screen, the Jaridians still exhibit an active shaqarava, an energy-channelling organ that has been dormant in Taelons for thousands, if not millions of years. This indicates that the Jaridians likely split from the Taelon species some time after the Kimera interfered with their species' evolution. This split likely occurred at least since the beginning of the Taelon-Jaridian war, eight million years ago.
When the Taelons and Jaridians split apart, both species lost important elements of the physiological make-up. The Jaridians, while able to reproduce freely and rapidly, have tragically shortened lifespans. Upon death, Jaridians combust: this may be a problem caused by an inability to control the energies of the shaqarava. Another theory is that when the split between the two races occurred, the Taelons stole much of the Jaridians' core energy to lengthen their lifespans. This lack of core energy causes the Jaridians to have much shorter lifespans.
Only one Jaridian birth is shown through the series, which involves a (mostly) human woman giving birth to a hybrid human-Jaridian child. In this birth, the Jaridian father uses his shaqarava. The child is born in a flash of light, appearing outside the womb.
Jaridians retain an undetermined measure of the "core energy" that makes up Taelon physiology. While they do not seem to be energy-based beings like the Taelons, it still exists within them.
Society and culture 
The Taelons describe the Jaridians as being a bloodthirsty race, but this is only a very basic description of a sworn enemy. While most of the Jaridians seen are certainly aggressive, and often employ violence as an expedient solution to a problem, they will not hesitate to use a non-violent method if it will achieve their goals. They are also shown to care deeply about their family and race. Almost all of the Jaridians seen in the series are part of the Jaridian military, and so are not necessarily representative of the race as a whole.
Jaridians, like the Taelons, are said to not kill each other, and view the way with which humans kill each other in wars and in crimes as horrific.
The Jaridian government is referred to as an Imperium. Given that the Jaridian race has waged a successful interstellar war with the Taelons, it seems likely that the Imperium is, at least by the time of the series, a well-organized government. The general impression created is that the Imperium is an aggressive organization lacking compassion, as it is shown that the Jaridians have destroyed outright many worlds that have allied, wittingly or otherwise, with the Taelons, in accordance with the Jaridian desire to wipe all trace of the Taelons from the existence.
There is a peace movement within Jaridian culture, a representative of which appears in the episode "The Summit" in season 4. It is mentioned in that episode that some members of the Jaridians have cooperated with Taelons to find a solution to their biological problems at undisclosed times in the past. The impression is made that cooperation dates back at least several centuries.
The surface of the Jaridian homeworld is briefly seen in the third season, it appears to be quite rocky, with cities or possibly industrial complexes visible in the background. As the Taelons, Jaridians and Atavus (in the final season) each refer to their homeworlds, yet each are supposedly evolved from the same ancestors, it is possible that any or none of these planets could be the original homeworld of the divergent species.
Jaridia's fate is not conclusively known: in season 5, Renee Palmer states that the planet imploded, but there is no known means by which she could have found this out. The Jaridian species themselves are said to be facing death en-masse from their biological problems, but this would seem insufficient to cause such a cataclysmic event.
The position of Jaridia is not known for certain either: the planet is said to be in the Tau Ceti system. This is a real star that is relatively close to Earth (just under 12 light-years) in the consetellation Cetus. In the penultimate episode of Season 4, the character Liam Kincaid refers to the location as "a double star in the constellation Cetus". This is confusing, as though this would seem to refer to the real-world Tau Ceti, in reality, Tau Ceti is not a double star.
Given that Jaridian forces have travelled several million light-years to other galaxies, but have yet to come into close contact with Earth, this casts doubt on the idea that the Tau Ceti mentioned can be the Jaridian homeworld. Debate among some fans nevertheless remains quite heated on the subject, linking in with the debate over the FTL capabilities of the Jaridians. In the real world, Tau Ceti would be unlikely to provide an environment suitable for the formation of a stable rocky planet.
Jaridian technology is crystalline in appearance and highly adaptive. The Jaridians deploy probes to gather information, but also as offensive weapons, as probes have consistently shown themselves to be capable of withstanding heavy fire.
Jaridian starships come in a variety of designs, the most powerful of which appears to be the Sokara-class cruiser. These ships have armaments powerful enough to destroy the surface of entire planets. There are several of these vessels in service.
The Jaridian fleet does not possess interdimensional technology, and are significantly slower than Taelon craft. There is some debate as to whether or not the Jaridians have the capacity to travel faster than the speed of light at all, though many fans believe that, even over the course of millions of years of warfare, the Jaridians would require some FTL capacity. In the final episode of the fourth season, a Jaridian cruiser may be travelling faster than light, but is not in an interdimensional pathway.