Navareans (N. primus) are the only sapient species on the Navarean worlds, and as such are the primary intelligent species in the Navareo Empire. Navareans are classes as planetary animals characterised by their humanoid stature which is visually remarkably similar to their evolutionary analogue in the PC-3 evotrail.

The primary difference between the humanoids of the PC-3 (Eris, Sol) and PC-1 (Navareo) evotrails is the internal structure of their organisms: Whereas Tallisites (T. primus) and Humans (H. sapiens) 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. In fact, 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, since experimentation with the PC-1 evostrain suggests otherwise.

Chronology

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-Earth 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 years provided the worlds in the chain with a habitable atmosphere.

Anatomy

The Navarean anatomy is a unique and complex structure that allows Navareans to withstand various environmental conditions while maintaining their efficient biological functions. Among the key features of their anatomy are the dual vascular system, redundant organs, and a sophisticated immune system that utilises calcification as a defence mechanism.

Dual Vascular System

A fascinating aspect of Navarean anatomy is their dual 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 design contributes to the Navareans' renowned longevity and remarkable ability to recuperate from injuries.

The process of changing between the dual vascular systems is an essential aspect of Navarean anatomy for several reasons. Without this changeover, the overall health and resilience of the Navareans might be compromised.

Periodic Changeover

Under normal circumstances, the active vascular system alternates two to three times a year. This periodic changeover, which takes about a week, 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.

Repairing Damaged Organs

When damage to an organ or several organs reaches a critical threshold, the vascular system that contains the affected organ enters the REPAIR mode, 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.

Prevention of Infection Spread

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.

Compensating for Lost Function

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 REST mode, 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.

As the understanding of the Navarean anatomy and its dual vascular system advances, researchers are exploring the possibilities of organ transplantation as a method for repairing or replacing organs in permanent REST mode. This area of research holds promise for improving the quality of life and longevity of Navareans afflicted with organ failure.

Compatibility of Donor Organs

In order to conduct successful transplantation, the compatibility of donor organs with the recipient's system must be assessed. Studies have been initiated to determine tissue typing methods specific to Navareans, along with the development of immunosuppressive medications that could reduce organ rejection while maintaining their unique calcification-based immune response.

Artificial Organs

Another research avenue involves the creation of biomechanical or bioprinted organs. These artificial organs could be designed to function seamlessly within the Navarean anatomy, lessening the need for a perfect donor-recipient match and potentially alleviating the scarcity of available organs for transplantation.

Integration with Inactive Vascular System

Further investigation is needed to understand the intricacies of the Navarean anatomy when a transplanted organ is connected to an inactive vascular system. Researchers aim to devise ways to effectively integrate the new organ into the existing vascular network and stimulate it to exit permanent REST mode. Restoring the dynamic balance of the dual vascular systems will be crucial for a successful transplant procedure.

Ethical Considerations

Organ transplantation research in Navareans must address various ethical issues, such as the origin of donor organs, informed consent, and potential social consequences. In-depth ethical discussions and guidelines will be necessary to ensure that transplantation procedures respect the Navarean culture, while advancing medical knowledge and practice.

In conclusion, the prospect of organ transplantation to repair or replace organs in permanent REST mode in Navareans presents a promising area of research. Exploring compatibility, artificial organ development, and integration with the inactive vascular system, alongside addressing ethical considerations, may lead to significant breakthroughs in Navarean healthcare and further improve their unique anatomy's resilience and adaptability.

Immune System and Calcification

Navareans have a sophisticated immune system that utilises a process similar to calcification to isolate and combat infections or diseases. This unique biological response enables Navareans to rapidly recover from diverse health issues while preventing the spread of infections to other parts of their bodies.