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Welcome to the very first blog of this series! I'm sure your very interested in what this blog includes. I decided to dedicate the first blog to the most well-known monster in the franchise, Rathalos, and his female counterpart, Rathian plus their subspecies because of their symbolism in MH. Now, then let's begin.


Rathalos and Rathian are part of the Flying Wyvern class with three subspecies: The Old World subspecies (living in the areas around Kokoto Village, Dundorma, Minegarde Town, Jumbo Village, Mezeporta Square and Pokke Village), the New World subspecies (inhabiting areas around Moga Village, Loc Lac City, Yukumo Village and Port Tanzia) and the Val Habar Subspecies (inhabiting areas around Val Habar, Harth, Cheeko Sands and Cathar). The Val Habar subspecies isn't completely confirmed though, so it's still unclear if it is a subspecies or not.

Each of the subspecies has the same genetic mutations that result in the Azure Rathalos/Pink Rathian and Silver Rathalos/Gold Rathian. Although so different they aren't subspecies (even though they are called that by the guild and in Japanese) but gene mutations (similar to the black panther, which is only a melanistic leopard or jaguar, and albinistic animals) that affect the coloration of their scales. It also seems as if the mutated genes affect both genders but the gender-exclusive genes they cooperate with develope the different colors. So both the Azure and the Pink morph are created by the same mutation.


Rathalos and Rathian are a species of bipedal wyverns that have rough, spiny scales covering their bodies. The form of these scales depends on the subspecies. Old World Raths have bolder, more edged scales than New World Rathalos which look a bit smoother. A relatively big head with pointy teeth sits at the end of a rather long neck. Raths are visual monsters that rely on their excellent eyesight as they attack prey from above. This also results in a relatively large brain. Several plates, bigger than normal scales, grow on the back spine which ends in a long, flexible tail with the characteristic spiked club at the end. The tail evolved as counterweight to its body and head, and helps steering while flying, on the ground it is a weapon to strike assailants down. The legs and feet are very strong as they need to lift the weight of its prey to their nest.

Interestingly this species has two forms of polymorphism, for once the sexual dimorphism and second the dichromatism (two forms with different coloration) for both genders. The term polymorphism only applies to sympatric living animals/monsters which means in the Misty Peaks is a case of trichromatism (three forms) for Rathian because all three "subspecies" (more precisely: morphs) live in the same area.

The differences between the males and females are visible at the head. While Rathalos have seemingly broader faces because of the bigger scales on the side of their head, Rathians don't have them but a spike on the chin. This spike is used for piercing smaller prey to feed them to the youngs. Unlike Rathalos Rathians grow on their upper back a fur of needle-like hair. The club on the tail also differs depending on the gender. While Rathalos have big spikes at the side of the club and one big one at the end, the tail of Rathian grow several thin, spiky scales at the end and the other scales are rough. But the sexual dimorphism is most apparent with the coloration. Rathians have a overall green body with darker underside and a brown pattern on its wing skins. In opposite to that Rathalos are mostly red with black markings on the back while the belly is a consistently dark grey color. The effect of the mutations replaces the prominent coloration with completely different colors. Specifically Pink Rathians are bright pink where the regular Rathians show green, the even rarer Gold Rathian shines in a glistening golden color. On the male side the black patterns stay the same while the Azure Rathalos has a sky blue coloration rather than red and the Silver Rathalos is bright silver in these areas.

This leaves us with the question: Why this difference in color? And why exactly these colors? The second question is easier to answer but has a follow-up question that includes the individual quantity of each morph. Rathalos has this red-black coloration for two reasons: 1. Camouflage in its main habitat, the volcanic belt. 2. Intimidating other monsters that come too close to the nest which is built in areas with vast plains in more temperate climate zones. The volcanoes are much more dangerous, through its coloration it can stall fights with perilous opponents. In the areas it breeds the monsters are less dangerous and it is better to scare them away, so the red and black pattern works like a warning sign for other predators. Rathians green color can be explained by the same patterns but it adapted to the forests and jungles they inhabit. While Rathalos roam around flying through vast areas it still applies as they prefer volcanic areas. That explains the normal coloration of the Raths but what about the mutations? And can it also explain the difference in the numbers between the three morphs? The answer is partly. The Red Rathalos and Green Rathian morph are the most spread followed by the Azure and Pink morph and the rarest is the Silver and Gold morph. While Azure Rathalos are seen in the volcanic belts, their preferred habitat are areas with water bodies where the sky blue coloration isn't as prominent. That means the azure morph has a similar situation as the normal Rathalos but has an advantage. It isn't as visible in the sky as the red variant and has a bigger chance for getting prey. Then why are they less frequent than the regular Rathalos? I guess that the reason is the female counterpart of the Azure Rathalos. Unlike the normal Rathian the pink coloration stands out in any area it inhabits. That gives Pink Rathian a much worse condition and probably cancels out the advantage Azure Rathalos has over the Red morph.

Now, to get back to the other question: Why does Rathians color differ from their male counterparts? We know many animals that don't have this sexual dichromatism, like wolves, cats, bears etc. This kind of polymorphism often occurs with birds (1.). The color of an animal can either provide camouflage or give the owner an intimidating appearance. But that doesn't only apply to other individuals of one species with the same gender or enemies but also individuals of the other sex. And this situation which one individual chooses its potential partner by look is called sexual selection. The choosing is almost always done by the female while the male tries to seduce her with his beautiful coloration. The brighter the colors the better the chance to be the lucky one who can breed. Let's apply this knowledge at the case of Rathian and Rathalos. Because the regular Rathalos is the more colorful counterpart, I believe Rathian is the one who chooses her partner. The color contrast, brightness and other signs can show the female how healthy the Rathalos is. These parameters are worse if the judged male is starved, injured or ill. With this knowledge the Rathian can analyze how reliable the Rathalos is like if he can hunt prey well to help feed the youngs and similar. This evolutionary pressure leads to more colorful males. But Rathalos is a special case. While in the mating area it is colorful it uses this coloration for camouflage in its normal habitat. So rather than more colorful the female probably judges the camouflage ability of the males that at the same time provides intimidating features for other monsters near the nest.

Anatomical peculiarities

Significant characteristics of the Raths are their flame sacs, multiple sacs that store a burnable fluid. This fluid inflames at contact with air which happens in the throat of the Wyvern. This means every time a Rath uses its fire breathing ability it causes burn injuries in the throat area. But there are no consequential damage as the mucous membrane heals fast. Rathian seems to have a stronger fire power compared to Rathalos. This may be a consequence of the more terrestrial life style in opposite to the males. This species has strong and wide wings and is known for its flying abilities. Especially the males are good and frequent flyers, for that known as the King of the Skies.

A very interesting matter is the venom Raths produce. While the poison gland leads to the tail and to the back hair of the female, Rathalos inject the venom with his talons. This again is the result of the different life styles the different sexes lead. While Rathalos attack from above with their claws rather their tails or teeth, Rathian uses the tail more often while close to the ground and the hair on the back protects it from attacks coming from above. But how is it possible that one species has two different ways of excreting poison depending on the sex? I believe the toxic gland has canals that lead to both tail/back hair and talons but the (sexual) hormones causes one way to wither or only one way to develop. For location of the poison gland an autopsy would be helpful but that's out of question. But as two ways go to a destination close to the spine I think it may be located close to the spinal column. But this is just a guess.


Rathalos and Rathian are top predators in most areas they live in but are in competition with many other predators owning this status (especially in the volcanic belt). To the relationship with other monsters later more. Raths are very territorial having vast territories they harshly defend from other members of their species and other threats. The wide matrix of movement that is possible with their flying abilities and the need for high amounts of food due to their size suggest a big territory of several hectares. It's unknown if Rathalos and Rathians are as aggressive in their habitats other than the nesting ground as inside but the territorial behavior is visible there as well. Known nests that are used regularly are located on the Deserted Island, at the Forest and Hills and the Ancestral Steppe]. The Raths have a distinguished sexual role allocation when nisting. While the female looks after the youngs the Rathalos patrols the surroundings in search for threats. This can be seen aligned to their terrestrial and aerial living style respectively.

In search for prey Raths roam around the area in air. Attacks usually ensue from the air with impact of the claws in the body of the prey. Rathalos can inject poison with this but it seems to be more of a mechanism to fight back enemies rather than used for taking down prey like the non-toxic strike of the Rathian implies which attains the same outcome. They sleep in secluded areas far from threats and if another predator appears against the odds the camouflage helps deceiving their eyes.

Rathalos and Rathian are often referred as monogameous creatures but there is no known evidence that shows this clearly. But there are signs that suggest the correctness of this statement nevertheless. First of all as both parents help raising the youngs a bond of trust between Rathalos and Rathian is indispensable. This bond of trust needs to be as strong as it gets because if one of the parents leaves the partner behind the raising of the babies is in great danger. Because the bond is that strong searching for another partner every mating season is very inefficient. Monogameous bonds achieve even higher trust as the partners can count on each other every mating season. Also the relationship of both male and female seems to be very intimate even after mating. They help each other if one faces a peril and are worried about the well-being of the other partner. Such strong bonds cannot be gained with each individual in a short time and it can be assumed the same partners get together in mating season. It's apparent that Rathalos and Rathian only stay together in mating season and live on their own outside of this time. This actually is a good indication for monogamy in this species (2.).

It's unknown how Raths react to other individuals of their species and what is the social structure between them. For my part, I assume a similar system to carrion crows (3.) meaning pairs of them occupy a limited amount of territories and breed while other pairs fight for a territory with the owners. This field of behavior demands more exploration. Same goes for the mating itself but I guess there won't be released much information about this. The average amount of eggs layed seem to be about 3-4 as seen in the ecological video. The incubation time for the eggs are not known. The females feed the youngs which are early able to eat flesh with small bits of meat pierced on their chin spike. It's unknown at which age the small Raths learn flying and when they finally leave the nest.

Niche in the ecosystem

Raths are carnivorous and top predators in any area they live in but are surpassed by some other monsters. Both male and female hunt alone. Preferred prey are Aptonoths and Kelbis in almost all areas and Slagtoths in moist forests (Rathians) and the volcanic belt (Rathalos) as well as Gargwa in some areas. For Old World Rathians potential prey are Velociprey/Velocidrome and relatives, Mosswine, Bullfango/Bulldrome, Conga/Congalala and Yian Kut-Ku as well as young or injured indiviuals of other monsters of the forests, and Cephalos and maybe even Cephadrome in the desert. The males of the same subspecies may additionally subsists on Apceros and young or injured individuals of other monsters in the volcanic areas. The New World Rathian preys on Jaggi/Jaggia/Great Jaggi and relatives, Ludroth, maybe even Royal Ludroth, Arzuros etc. The male counterpart may hunt upon Rhenoplos, Volvidon, Uroktor etc. The Val Habar subspecies devours a mix of both other subspecies as well as Tetsucabra, Kecha Wacha etc. For the Azure morph the prey spectrum moves closer to the Rathian's one. Silver Rathalos and Gold Rathian have a much smaller diversity of monsters they hunt as they live much more secluded.

Foot notes

  1. Amotz Zahavi has created an interesting theory about why birds evolved almost obtrusive colorations and unusually big tail feathers and such, known as the "handicap principle". While betraying would be better for the individual that is in the lower tiers and would probably neber be chosen by the females pretending it is much more healthy than it actual is in time females will evolve ways to see through these deceits. So honesty's the only way. The handicap principle now explains why it led to bright colors and long appendages in spite of the fact that those would give them a disadvantage as predators can more easily recognize them. Let's look at the peacock as an example. To show that it is better than another peacock on the same level of health it evolved longer tail feathers (of course not intentively). This is like a call meaning "Look, I'm here even though I have this handicap! I'm healthier than others!". Additionally not so healthy males don't have enough nutrients and energy to even grow their tails that big so it is pretty easy to see for the females which of them is healthy.
  2. Wandering albatrosses have a similar system between males and females and it's monogameous. Interestingly the first time the male impresses a female with its dances it doesn't lead to mating but another later mating season is their first time to nest. The first dance seems to be a test of trust. If the male doesn't hold out the whole ceremony it won't get together with the female. Other than in mating season wandering albatrosses normally never come to land only soaring over the sea. This life style seems to need a solid relationship as they mate only in two years intervals and searching for a new partner every time is too time and energy consuming.
  3. Carrion crows have a very interesting social system. In mating season two castes are present, one that breeds, another that doesn't breed. The nests are limited so the "breeders" need to protect their territory so they are able to breed while the other caste tries to take over one of the nests. This leads to an additional regulation of chicks. Ironically this is the reason why shooting these crows by hunters doesn't regulate but help the populations as hunters mostly shoot non-breeding individuals what results to less pressure on the breeding population and more surviving youngs. This mass shooting, to add even more irony to it, happens to help singing birds population which is also the order to which crows and ravens actually belong. It's not rare that young crows (mostly former children) help a pair with the brood care of a breeding pair. This helps them grow experience for later when they have their own youngs.