Rathian Ecology

Disclaimer: This is merely a plausible explanation for the monster(s) in this article, and should not be considered canon.

In-Game Information
Rathian is the female version of the Rathalos. It shares many characteristics with its male counterpart, although Rathian tends to patrol its territory on the ground. Its tail spikes are filled with poison.

Taxonomy
A true wyvern, Rathian display all the trademark characteristics: large wings, forelegs only, and a long tail. Its build is slightly stockier than a Rathalos' and its profile is less aerodynamic due to its spiked barbs. Rathian may grow slightly larger than Rathalos because of its terrestrial nature.

Habitat Range
Rathian can survive in almost any territory as long as temperatures are right for rearing young and food supplies are plentiful. However, they prefer areas with good nesting sites and easy to navigate terrain. Mountaintops and caves serve as excellent nesting sites.

Ecological Niche
An Alpha Predator, Rathian is the nestmate of Rathalos, and together, the two actively patrol large territories from both land and air. After giving birth, Rathian and Rathalos, like most predatory raptors (which they seem to resemble), will take turns caring for and feeding their young, swapping parental duties after their mate has returned. However, a Rathian is more likely to devote more of its time to rearing the chicks than her male counterpart. A very plausible reason for this is due to the fact that Rathian have slightly slower metabolism than Rathalos, since walking takes far less exertion than flying. This trait allows them more time to conserve energy and divert attention to the feeding and protecting of their young rather than themselves. Particularly favored food for Rathian would be Velociprey or Jaggi, as the lean, protein-rich muscles of these creatures and relatively weak skin are easy for young to digest and yield high nutritional value. The young of Rathian and Rathalos apparently do not sport neither the dark red scale colouration nor a deep green scale colouration that distinguishes each hatchling into being a Rathalos or a Rathian respectively when it reaches full maturity. Instead, hatchlings initially have a grayish, dull scale colouration, thus their true gender at this age can only be determined by checking the reproductive organs. Hatchlings are taught how to run, hunt and catch prey like Kelbi by the Rathian, and later, when the hatchlings have developed wing muscles, they are taught how to glide and hover by the Rathalos. Once the adololescents' hunting skills have been perfected, they should have already developed the scale colouration unique to their gender, and finally leave the nest to forge solitary lives until maturity, to start a family of their own.

Biological Adaptations
Rathian has a poisonous tail, but lacks the poisonous claws of the male wyvern. It instead has developed poisonous barbs resembling coarse black hair that deter most attackers. The roar of a Rathian is just as fierce as Rathalos' and its land-based maneuverability is even greater. Rathian has the ability to perform backflips to knock a foe out of its way while simultaneously poisoning them. Rathian's dark green coloration serves to camouflage the creature so it may more efficiently hunt prey.

Behavior
Rathian is very territorial, choosing to patrol from ground more than its male counterpart. It will become very aggressive to potential threats, especially when it is taking care of its young. As seen in certain quests, Rathian will pursue any hunter seen carrying one of her eggs, and seems to have a sixth sense about pinpointing their location. Rathians, like many wyverns, show maternal instinct by caring for and raising their young for a period of several years before they are old enough to fend for themselves. Rathian also form a lasting bond with their mate, being one of the few wyvern species to show cooperation and monogamy between adults.