Navareans (N. primus) are the most common and widespread species of humanoid in the galaxy. They are characterised by their unique physiological and anatomical features, which have been adapted to a wide range of environments across the galaxy. Navareans possess a high degree of genetic diversity, which is reflected in the variance of physical appearances, skin tones, and abilities within the species. This diversity is a result of their long history of space exploration and settlement on various planets, leading to isolated populations that have adapted to their specific environments.
Navareans, similar to other humanoid sapient species, are highly social and commonly form a densely interconnected network of social structures and civilisations. Due to the fragmented structure of Navarean society, a wide variety of values, social norms, traditions and conventions underpin interactions of Navareans, which are not always compatible with each other.
It is commonly believed that Navarean life was seeded on all five major Navarean planets independently of each other. However, due to the host of differenced between Navareans and other sapient species, it is believed that Navarean life was seeded by a different precursor comet. The Navarean precursor comet is called PC-1.
Some xenobiologists use the term "Navareans" to describe all members of the genus Navareo, but it's commonly understood to mean Navareo primus, the only surviving species. The other, now extinct, members of the genus are called archaic Navareans, and the term "modern Navarean" is used specifically for N. primus to set them apart. Anatomically modern Navareans appeared roughly 100,000 years ago on Navareo I, II and IV, evolving from N. precessor, a related species. As they migrated onto other areas of their planets and Navareo III and V, they replaced and interbred with local archaic Navarean populations. The extinction of these archaic Navareans, including Neanderthals, is attributed to various factors such as competition, violence or interbreeding with N. primus.
The primary difference between the humanoids of the PC-3 (Eris, Sol) and PC-1 (Navareo) evolutionary paths is the internal structure of their organisms: Whereas Tallisites (H. sapiens tallis) and Humans (H. sapiens terra) have a simple cardiovascular system supplying the body with oxygen using hemoglobin as an iron-based oxygen transport protein, the Navarean cardiovascular system runs at much lower pressure using two smaller hearts in both sides of the body. This also makes the Navarean body run at much lower temperatures and much lower overall power, requiring less calorie intake and less oxygen. The oxygen transport protein in Navareans is hemerythrin, which contrary to its PC-3 analogue hemoglobin not only causes oxygenated blood to appear purple, but also operate a quarter of the oxygen saturation efficiency.
Navareans are highly resistant to radiation damage in their DNA and mutations. The star Navareo has an unusually high output of ionising radiation, which coincides well with the higher radiation resistance a triple-helix DNA causes in Navareans. It is unknown whether or not these two things are causal.
Scientists still debate as to the origin of Navarean life. The predominant theory is that of precursor comets, large celestial objects that carry organic compounds known as evolution starters, being responsible for the beginnings of organic like on these homeworlds. This theory is partially proven and disproven simultaneously by the existence of the Tallis-Terra link.
According to radiometric dating estimation and other evidence, the Navarean Chain (the name for the collection of five planets within the habitable zone of the star Navareo) formed over 6.2 billion standard years ago. Within the first billion years of the Navarean Chain's history, atmospheres and protective atmospheric layers did not exist and were generated approximately 1.3 billion years after the planet's creation by the introduction of organic compounds and certain alphabacteria. These organisms are able to provide oxygenation through a process similar to photosynthesis, which over the course of several million years provided the worlds in the chain with a habitable atmosphere.
Despite having an appearance very close to that of H. tallis, Navareans have very different physiology. Chief among them is their dual-redundant vascular system comprising two sets of circulatory networks. The system allows for each half of the body to function independently, providing a greater capacity for maintaining the health and wellbeing of individual organs. Additionally, special valves in the extremities enable blood flow from either circulatory system, ensuring adequate oxygen and nutritional supply.
The brain and skin are shared by both vascular systems, with a diverter valve in the brain that can effortlessly alternate between the different circulatory networks. This adaptation provides increased resistance and adaptability for Navareans under various circumstances.
In the Navarean torso, redundant organs provide an added layer of resilience and functionality. These duplicate organs essentially act as a backup for their counterparts, ensuring that if one organ fails, the other can take over its functions. This contributes to the Navareans' longevity and remarkable ability to recuperate from injuries.
Under normal circumstances, the active vascular system alternates two to three times a year. This periodic changeover, which takes on average about 10 days, is vital as it ensures that both systems remain in optimal condition. During the transition, the Navareans may experience fatigue and lethargy, but the resulting benefits ensure a healthier and more robust organism.
When damage to an organ or several organs reaches a critical threshold, the vascular system that contains the affected organ enters a mode of autotherapy, and the other vascular system becomes active. The changeover allows the damaged organ to be repaired or quarantined and broken down without imposing additional stress on the rest of the body.
One of the primary purposes of changing the systems is to contain infections and prevent them from spreading to other organs via the bloodstream. The immune system can then focus its efforts on healing the affected organs in the inactive system while the active system continues to support basic bodily functions. This separation protects the entire organism from succumbing to infection.
In the case of a damaged organ whose function is vital for the organism's survival (e.g., digestion, respiration), the vascular system containing that organ enters a permanent state of hibernation, allowing the other system to compensate for the loss of the essential functions. This adaptation provides Navareans with an increased chance of survival even when facing potentially fatal organ failure. Researchers are exploring the possibilities of organ transplantation as a method for repairing or replacing organs in permanent hibernation.