A comprehensive study of the vorcha was recently completed by the salarian STG, and its non-classified findings have been published for the viewing of scholarly communities throughout the galaxy.
Biology:
It has been speculated that using the vorcha's adaptability can have both economic benefits for the rest of the galaxy and humanitarian benefits for the race itself. Tests run by top-level salarian geneticists indicate that infant and pre-born vorcha have a near blank-slate like quality which is not found in any other known sentient life-form. The vorcha equivalent of DNA codes for basic geno-and-phenotypic qualities only, and their non-differentiated cells begin low-level specialization to outside stimulus almost immediately after birth. Thus, as most vorcha are exposed to violence adapt to it from infancy, their bodies rapidly develop to handle the physical and mental strains necessary to cope with living in their culture.
It has therefore been postulated that removing a vorcha from this environment and raising them in a controlled lifestyle could possibly induce adaptation that would result in an individual that is far more capable of coping with normal galactic society. Stimulating certain areas of the brain may enable a vorcha to grasp concepts and ideas previously thought beyond their reach due to their short life-span. In this way, the perceived stupidity of the race may be "curable". However, such an endeavour would be a serious undertaking, as there are over a billion registered vorcha throughout the galaxy, and an estimated population of almost double that. No humanitarian organization has the wherewithal to even attempt such an undertaking, and there are far more pressing concerns in the galaxy than saving such a marginal race, who most consider scavengers.
Vorcha reproduce sexually, meaning that a male's sperm must fertilize a female's eggs in order to produce offspring. Male vorcha have more pronounced cranial horns than females do, and are generally taller and thicker at the waist. When a vorcha is sexually aroused, their reddish blood flows to the cranial horns, coloring them a reddish-orange color and indicating that they are ready to mate. Male vorcha possess a phallus, which is always erect but is stored internally in the body for heat regulation. It can be extended at will, and is covered in short, pointed spines all along its length. Vorcha semen, when ejaculated, is a black-colored liquid, which quickly congeals due to the absence of the vorcha-equivalent of testosterone. The sperm-like cells remain alive in this sponge-like substance for two months, living inside the female long enough for her to release a fertile egg and conceive. Thus, nearly all vorcha mating rituals end in a pregnancy, which usually lasts just over two months.
Vorcha give live birth to their children, and have one only offspring per birth. Excess semen that remains in the female vorcha's womb-analogue is broken down by a new hormone introduced upon a successful pregnancy. The resulting substance is used as nutrients for the new embryo as it grows. A vorcha child has teeth upon birth, allowing it to chew solid food. Vorcha have a rapid growth cycle, and typically reach maturity by their first year of age. There is very little to differentiate a vorcha that is one year old from one that is ten, twelve, or, even seventeen, biologically speaking. It is possible to do so through examination of the amount of scar-tissue found on a vorcha's body, but that has more to do with their culture than any naturally-occurring part of their lifecycle. Towards the end of their eighteenth year, the vorcha biology begins to deteriorate very rapidly. By the time they are nineteen, most vorcha are sickly and very weak. As this would put them at a distinct disadvantage in their society, most vorcha do not live past twenty. Either they killed, they starve after being left behind by their tribe, or they simply wither away and die naturally.
Vorcha women are somewhat smaller than their male counterparts. On average they are several inches shorter, and thinner in the waist and arms as well. For this reason, female vorcha are not used as warriors, because they are usually born at a 3:1 ratio with their male counterparts. Most of the time the female's smaller size is a disadvantage during vorcha mating rituals, when they are often expected to fight off the males in order to test their strength and force of will.
History:
What records remain on the vorcha's homeworld of Renval are scattered, filled with bias, and are therefore extremely contradictory. Even so, a few impartial facts can be gleaned from the rubbish. Vorcha society peaked around 500 BCE, and was the equivalent of early 18th century Earth at its zenith. Independent nation states eventually solidified their rule over large parts of the planet, and technology had advanced to basic industrial production, which was primarily used for military purposes. Rudimentary firearms had made their entrance onto the world stage, though they made little impact in the constant warfare on the planet. The vorcha's massive increase in population, a result of somewhat improved medical knowledge, better transportation, and the ability to mass-produce food and other equipment brought on by industrialization, failed to elicit a stabilizing effect on global politics, and instead made the fighting over the ever-decreasing resources of the planet all the more fervent. This was the status-quo for roughly 200 years. Eventually, the vorcha nation-states collapsed under the weight of their own populations, which they could no longer feed or support, and the fighting became more localized. What technological advances there had been were lost in the resulting chaos, and vorcha society grew more isolated and clannish with each generation.
This persisted until the advent of a batarian exploratory probe which made landfall in 145 probe was promptly dismantled and scavenged by the vorcha that found it, but the batarian scout frigate which landed in search of it was greeted with more caution. After ascertaining a fairly accurate understanding of the situation on the planet, the batarians left after just three days, intending to ignore the vorcha entirely. However, nine vorcha had stowed away on their vessel. And that was how this curious, violent race was introduced to the wider galaxy.
Over the next several centuries, the vorcha population in the galaxy slowly grew. Relatively easy-to-access resources, combined with their adaptability and physical hardiness, as well as an explosive birth rate meant there few places the vorcha could not live, and thus breed once they had arrived. Early vorcha "colonies" include Wrill, Garvug, and the Omega space station. Vorcha emigration was greatly aided by Ganar Wrang and his new Blood Pack, whose frequent visits to their homeworld since early 2165 have transported hundreds of thousands of vorcha from Renval. This has catapulted the vorcha race from a fringe nuisance to an almost integral part of the galaxy's underworld. Initial contact with the Alliance was made in 2178, by which point the total vorcha population was estimated to have been well over one billion. Since then the vorcha have continued to insinuate themselves into the seedier parts of the galactic stage. Whether the rest of the races want to admit it or not, the vorcha are here to stay.
Notable Vorcha Clans:
Stone Claws: This clan somehow managed to maintain control of one of the original nation states for over 140 years, living on the then-fertile northern plains of Renval. Given the short-lived nature of the vorcha, and the transience of their politics, this is quite an impressive feat.
Rock Bones*: This vorcha clan is believed to be responsible for the advances in vorcha technology that led to their peak level of industrialization. Most of the weapons that have been unearthed by salarian archeologists bear the same sigil, which all can be roughly translated to "bones of rocks."
Blood Pack: Perhaps one of the most well known mercenary companies in the galaxy, the Blood Pack can trace its origins back to a small, previously-unknown vorcha gang on Omega. The gang's only advantage was being in the right place at the right time to be noticed by one Ganar Wrang, who promptly took control by killing their leader. The rest is history.
Gore Killers*: This particular vorcha gang has little to be proud of, except perhaps for its endurance. According to several different sources, these vorcha have lost almost every major fight they've ever been in, and have been "wiped out" at least five times. And yet, for whatever reason, the name continues to spring up among the tens of thousands of vorcha on Omega.
Krogan Tribes**: The krogan clans which have "domesticated" vorcha raise them in a very unique method. At birth, a vorcha is chosen for either a life of labor, administration, or warfare. The vorcha destined for combat roles are raised in a way more in keeping with their culture, with the best examples often sent as tribute to the Blood Pack. The labor vorcha are given tools instead of weapons, and are sent out as basic workmen throughout krogan territories. Though many krogan deny this, these vorcha are little better than slaves. They can mine, build roads, or even do basic electrical work if they're particularly smart. The administrative vorcha run the the day-to-day lives of vorcha that live under the krogan rule. They are taught reading, mathematics, and how to use VIs and other modern computing technology. The krogan don't necessarily see these vorcha as smarter than the others, viewing them instead as performing a different sort of "basic service" that they can't be bothered to do themselves.
*-Note the creativity with which the vorcha name themselves
**-Krogan tribes are a collective of formerly independent vorcha who have been conquered by one or multiple krogan clans and put to work for them.
Culture:
Vorcha culture has been relatively unchanged since their appearance in the galaxy almost eight decades ago. Their lifestyle, like their biology, is incredibly adaptive. Emphasis is placed on the survival of the group as opposed to the individual, and outside influences are usually met with extreme hostility. It is an unspoken imperative that tribal culture must be preserved across generations. This is probably due to the short lifespan of individual vorcha. It seems to be completely up to the tribe leader's preferences how large the tribe can become. Some grow into the hundreds, or potentially thousands, while others split apart into separate groups after reaching fifty members. Some vorcha tribes will claw each other apart for a morsel of food, and others will distribute sustenance equally among themselves. Still other tribes may favor the leader and women while time are lean. If a vorcha does not like his leader's decisions, he can feel free to strike out on his own and start a new clan or tribe, or try and take leadership by force from the current tribal leader. Doing so may open up the tribe to instability and infighting, so this is only done by "alpha" vorcha, or those who are seen as particularly strong, clever, or charismatic by their brethren.
Vorcha children are raised communally by the tribe. It is an almost universal practice of a tribe to take the children of their defeated enemies, and raise them along with their own, regardless of what is done to the rest of the tribe. A vorcha child is seen as a potential resource first, and as a mouth to feed second. Even when times are lean, the tribe's children come first, because they are seen as the future of the tribe itself, most likely due to an individual's short lifespan. Killing a child is a grievous offense for most vorcha, as is allowing one to die due to neglect. Males are raised to be the protectors of the tribe, those who gather resources and fight their enemies. Women are kept safe, and are treated as being almost as valuable as the tribe's children, for it is they who produce the offspring. It is they who are responsible for raising the children, providing their food and teaching them how to speak, walk, and fight like a vorcha should.
Vorcha outside of tribes or clans are seen as little better than animals, and perhaps that is an accurate designation. So-called "feral" vorcha do exist in the deepest, most decrepit parts of places like Omega, where the light of civilization rarely shines. Little is known or understood about this particular brand of vorcha, other than they do not seek to join their comrades in comparably civilized society, and will attack any other life-form on sight, possibly to eat them.
Inter-tribal relations are entirely hostile. Vorcha tribes and clans have almost no diplomatic hierarchy of any kind. The singular solution to any conflict between tribes is to eliminate, dominate, absorb, or otherwise do away with the unwanted competition. This solution is upheld by nearly all vorcha, regardless of the size, strength, or resources of both their tribe and any of their enemies. Dealing with enemy tribes is again handled at the discretion of the tribal leader. A popular solution is to just kill enough of the enemy to force them to surrender or leave. Others include complete annihilation to make an example to other potential enemy tribes, but that is reserved for the more forward-thinking vorcha. An unusual, though quite effective, method is to wipe out the opposing tribe's leadership and then offer a chance for the remaining vorcha to be absorbed by the victors. Vorcha are usually subservient to their tribal leaders unless they wish to openly declare a bid for leadership, so there is little to fear from sedition or treason from the new additions.
Vorcha-alien relations are almost as hostile as those between opposing vorcha tribes. Vorcha are extremely communal and xenophobic, and as such are wary of alien influences at the best of times. They are normally only willing to even open themselves to an alien's presence when there is something in it for them: food, weapons, or territory. Vorcha gangs on Omega and elsewhere have been known to negotiate with other local gangs for all manner of resources, but this was usually done by the leadership, who are often considered to be the most "advanced" of the vorcha's species. The rest of the tribe is kept isolated from these outside influences, which could have a destabilizing effect on the leader's authority. A notable exception to the vorcha's closed-in pack mentality is the Blood Pack, which sees vorcha fighting and working and dying alongside krogan and, more recently, other galactic species. However, this is most likely due to the fact that the Blood Pack was originally a vorcha gang, and as such still maintains vestiges of that sort of tribal structure, even though it is currently led by krogan. It is speculated that the vorcha see the krogan as suitably "vorcha-esque," and view the Blood Pack as an acceptable replacement for the traditional vorcha tribal culture. Or, as the krogan see it, the vorcha could simply be slaves, useful as little more than cannon fodder and target practice, with opinions and thoughts that really don't matter. But again, no krogan would actually admit this publically.
During their peak, several of the nation states attempted to introduce deities that promised salvation for the planet if all of their enemies were destroyed. However, this was most likely a political ploy attempting to unify those nations against their neighbors, and not any sort of legitimate attempt to find salvation or solve society's woes. In fact, most sources from the time period indicate different religious establishments being directly controlled by the government. It is unknown how successful these "gods" were at gathering followers. Currently, vorcha seem to worship the very ground that they walk on. Not out of a sense of superiority for their species, but because they believe the world around them possesses a certain type of intelligence, which aids their bodies in adapting favorable traits. Some tribes contain a shaman, whose job it is to determine which adaptations are favorable, and how to best bestow them upon the entire tribe. Most vorcha in the Blood Pack still maintain this belief system some form, and will consequently refuse to clean themselves for at least one day (equivalent to about 19 Earth hours) after landing on a new planet.
Vorcha mating rituals are much like the rest of their culture: dependent on violence, but varying slightly from tribe to tribe. However, the basics remain the same. A male vorcha must fight off all competing males, and then fight the hardest battle against the female herself. Regardless of whether the female vorcha actually wants to mate or not, it is an understood norm of vorcha society that she must test the strength of the male by fighting him. If he is weak, he is not worthy of progeny. A tribe may or may not observe the mating take place, and there may or may not be religious significance placed upon the act as well. This would depend on the lineage of both vorcha, and the authority of the tribe's spiritual leader.
Noted Co-Conspirators: Pandu, Lazy Ush, Katana Angel, Dusty Robinson, Biscuitman (by accident), the most Enigmatic of Strangers, Schmidty, Tali's Biggest Fan, Mr. Feline Fanciness III