Kingdom: Animalia
Phylum: Chordata
Infraphylum: Gnathostomata
Superclass: Tetrapoda
Clade: Amniota
Clade: Diapsida
Clade: Sauropsida
Clade: Sauria
Clade: Archosauria
Clade: Avemetatarsalia
Clade: Dinosauria
Clade: Saurischia
Clade: Theropoda
Clade: Viverna
Superfamily: Gymnopteronoidea
Family: Caelincolidae
Tribe: Caelincolini
Genus: Mandibulaformia
Species: M. terribilis

Binomial Name

Mandibulaformia terribilis

Subspecies

Common rath, M. t. terribilis
Metallic rath, M. t. aurantia
Resplendent rath, M. t. resplendens

COMMON RATH

INTRODUCTION

The rath (Mandibulaformia terribilis) is one of three extant species in the genus Mandibulaformia and a member of the family Caelincolidae. The widely-used term common rath collectively denotes the genetic variations and phenotypic discrepancies documented between "Old World" and "New World" raths found on the five major continents. With some males exceeding 4.1 metric tons and a length of over 17 meters, it's one of the largest flying wyverns after the gravios, diablos (Aspiceros bicornis), and gureadomosu. The rath is one of the most widely-dispersed land species following humans and wyverians. Their range encompasses most tropical, subtropical, and temperate biomes at max elevations of 2000 meters, with average rainfall in certain climates oscillating between 21 to 170 inches annually. The rath is a least concerned species, due to extensive management from the International Hunters' Guild in regulating the number of individuals that can be killed or captured per year.

In the wild, the rathian /ˈræ.θi.ən/ has an average lifespan of 39 to 47 years, her longevity greater than that of the rathalos /ˈræ.θʌ.loʊs/ at a range of 35 to 42 years. They are typically seen in forested midland ecosystems, although habitation has been observed in deserts, highlands, and volcanoes. Raths are typically solitary wyverns when unmated, and only shift their lifestyle to cooperative hunting during and after the mating season. Prenuptial hunts — much like the ruts seen in even-toed ungulates (such as the kelbi) — are a part of the sexual selection process by which a rathian chooses a potential mate amongst various candidates (barring other selection factors). Raths are apex and keystone predators, although scavenging on carrion is estimated to contribute up to 35% of their diet. Direct attacks on human, wyverian, and lynian settlements are rare, and raths will seldom prey upon and consume them should they encroach their territory. Raths are predominantly diurnal, although nocturnal behavior is not unheard of.

Due to its widespread presence on nearly every continent, the rath is an easily-recognized animal symbol in many cultures. Depictions of raths date back to the earliest traces of civilization, with paintings of them seen on cave walls, masonry, and pottery. More telling is the presence of primitive weapons constructed from talons, claws, and spines, and armor fashioned from rath scales and plates, found at archeological digs. In ancient societies it was hailed as an omen of destruction, and its portentous reputation is alive and flourishing today. In many countries raths are hunted not only for equipment, but as parts of exotic dishes, with their ribs and loins in high demand in markets worldwide. Raths have been kept in menageries since before the formation of the Guild. Domestication and selective breeding of a related rath ancestor 40,000 years ago gave rise to the halk (Raptor domesticus).

ETYMOLOGY

The rath's name is thought to come from a phonetic spelling of the Old English wrāth meaning "rage," or the archaic wroth, "angry." The suffixes -ian and -alos are species-specific bound morphemes denoting the sex of the individual.

TAXONOMY AND EVOLUTION

The rath's closest living relatives include species in the genus Mandibulaformia: the black rath (M. obscura) and the crystal rath (M. alba), in addition to flying animals in the genera Aspiceros, Raptor, Barbarus, Selacharena, Metacarpium, Redimiculum, Squamasanguinans, and Plesichthys.

Subspecies

Today, 3 subspecies of rath are formally recognized, distinguished by scale coloration, size, and distribution (despite overlap of subspecies' ranges).

The common rath (M. t. terribilis) is the nominate rath subspecies, and shares its vernacular name with the species. Out of all three, the common rath is the most frequently encountered by people, due to it having a larger population than the other two subspecies and a greater geographic distribution across the globe. They thrive wherever there is prey, and have been known to colonize remote mountaintops and islands. The only places common raths are not endemic to is north of the Akra Strait, the Furahiya Mountains in northern Goldora, and the northeastern tundra of Fonlon. Temperature is the primary limiting factor for their migration.

The resplendent rath (M. t. resplendens) is a subspecies commonly found at the Misty Peaks, although its distribution encompasses much of the common rath's. The exact time of genetic divergence remains unclear, as do the selection factors behind its sexually dimorphic pigmentation. A lack of geographic isolation indicates that genetic mutation (not vicariance) resulted in this strain of rath, and that M. t. resplendens is simply a color morph. Yet a lack of inbreeding between M. t. terribilis and M. t. resplendens suggests that in spite of these minor phenotypic differences, each subspecies has its own shared mate recognition system.

The metallic rath (M. t. aurantia) is a subspecies with a much more narrow distribution, rarely seen outside subtropical swamps and jungles, sometimes roosting in abandoned human infrastructure at high elevations. They are named for the metallic sheen and splendor of their gold- (rathian) and silver- (rathalos) colored scales. Little is known about the behavior and biology of this subspecies, given its elusiveness.

CHARACTERISTICS

Physical description

The rath's upper jaw features nares on a keratinized sheath called a partial or receding rhampotheca, a reduced and vestigial epidermal layer that might have once formed a complete rostrum in early theropod ancestors. The overall body is covered in backswept keeled scales, with large, keratin spines jutting down the length of its back and ending on its flattened, club-shaped thagomizer. The sides of its jaws support a bony outgrowth (the "mandibles") attached above the mandibular notch. Its face is framed by prominent spines and facial crests, with two arrow-shaped ear-analogues. The wings sport keratinized spines along the radius, with unique patterns on the underside of the patagium. Rathalos coloration ranges from scarlet to merlot on its dorsal side, with paler beige scales. Rathians display either basil or olive green dorsal scales with a slightly duller hazelnut underbelly. Its feet are pamprodactyl.

All raths display dramatic sexual dimorphism; the rathian features more prominent needle-like spines on her collar, arm bones, and tail. These hollow spines connect to venom glands loaded with a potent necrotoxin. The rathian also possesses a single jutting "chinstrap" spine. The patterns on her wings consist of repeating eyespots. The rathalos has larger, more sickle-shaped "mandibles" above his jaws with distinct barbs. Rathalos tend to be slightly larger in size, with larger wings characterized by swirling flame-like patterns.

The rath ranges in length from 1653 centimeters to 1714 centimeters, although larger specimens have been recorded. An adult rath stands at 19 feet, with a wingspan of over 44 feet.

Mandibles

For decades, the nature of these mandibular accessories eluded biologists. While they superficially resemble the eponymous structures found on certain arthropods, they had no discernible function in prey-capture or mechanical digestion. They are, in fact, an ossified protrusion of the jaw. This feature, unique to the genus Mandibulaformia — for which the raths are named, mandibula "jaw" and formia "like" — may be used as an intimidation display against rival conspecifics, by flaring and flexing these appendages during confrontations. On rathalos the appendages are enlarged, with a distinct sickle-shape and several barbs; sexual selection by rathians suggests that they prefer males with the largest, most barbed mandibles. The size, color, and shape of the mandibles are associated with genetic precondition, sexual maturity, and testosterone production.

Flight

The bones of raths are pneumatized with criss-crossing trusses for structural strength. Respiratory air sacs often form air pockets within the semi-hollow bones of the rath's skeleton (a feature seen in flying wyverns and other theropods as well). Its many-jointed wings allow for flexible movement, compared to the rigid structure and paddle board-flaps of avian wings which limit their range of motion. Raths can achieve greater lift on the down stroke, during which the air vortex — which generates much of the lift in flapping-wing flight — closely tracks the animals' wingtips. In the upstroke, the vortex appears to come from the wrist joint. The articulation of the wings lends to the theory that rath flight, akin to the flight of chiropterans, is slightly more efficient than the flight of its avian relatives. Another specialized feature for flight is its posterior air sacs, which allow for unidirectional flow of air through its lungs via pressure changes. Its large keeled sternum creates a place of anchorage for the pectoralis, providing the all-important downstroke in powered flight.

At higher elevations the rath relies primarily on thermal soaring. Its preference for dry, warmer climates supports the idea that this predator takes advantage of hot updrafts to keep itself aloft, given the potential of being impeded by its own size and weight.

Fire-breathing

Close examinations of dentition and rath foraging behavior have shown an obligatory, partially omnivorous diet. Ingestion of cellulose is necessary in order to gain methane from microbial fermentation, the bacteria of which reside in the rath's gut. Rather than dispel the methane through biological processes such as eructation, the byproduct waste gas is housed in a specialized bladder-like organ called a flame sac. The conflagrant tube connects the contents of the flame sac to an opening above the pharynx. A membranous flap of skin at the aperture called the pyrostatic valve controls gas expulsion, allowing the rath to modulate the rate at which it releases methane. Highly-modified venom glands at the front of the upper jaw produce a hypergolic chemical that, upon contact with the reservoirs of stored methane, ignite. When muscles squeeze the glands, the venom is ejected in a forceful spray from the forward-facing holes on the fangs. This method of venom expulsion (and ignition) is what creates the stereotypical "fireball" effect that raths are known for.

Fire-breathing is a homoplastic trait acquired independently and multiple times by various species throughout the fossil record. It is an adaptation shared by members of the clade Viverna, in addition to other theropod groups, leviathans, and species found in the group Draconia.

BEHAVIOR

When not engaged in hunting, raths will spend about 12 hours per day to patrolling their territory. They are routinely active in the morning and late evening, with afternoons devoted to sunbathing. Thermoregulation in ectotherms such as the rath is achieved by radiating their wings on open, exposed areas, typically high rock faces where they build their eyries.

Intraspecific interactions

Raths are independent and reclusive animals, whose behavior toward conspecifics is modified according to circumstance. Outside of the breeding season, raths will challenge any intruders that they find inside the borders of their territory. Boundary indicators usually involve the rath scorching or charring visible rocky surfaces along the perimeter of its territory. On average, rath territories are 150 square miles. The culprits behind territorial confrontations are almost always nomadic adolescents that have not yet staked out areas of their own, and either accidentally stray within the border or are caught attempting to steal prey. Intruders are sometimes given the opportunity to flee if hunting hasn't been instigated. The resident rath will engage in ritualized aggression, via vocalizations (roars, bellows, hisses), flapping and wing pattern exhibition, scoring the earth with its claws, or a unique display known as fire gurgling, in which the rath will release just enough methane to cause small tendrils of fire to crackle and ooze out of its jaws. If the interloper is caught hunting, the resident rath will unleash a volley of fireballs from afar. If ranged attacks fail and the intruder doesn't retreat, it will attempt to fly over its opponent and rake them with its talons, or envenom them with the spines on its tail.

Raths reach sexual maturity at four years of age. During the breeding season, unpaired males will venture into the territories of rathians and engage in courtship displays to try and impress the female. If successful, the rathian will receive her new mate and form a monogamous pair that cohabits the same territory.

Rathians and rathalos will often coordinate their hunts, the rathian attacking from the ground while the rathalos strikes from overhead. Social behavior between a mated pair includes snout rubbing and synchronous sunbathing.

Hunting and diet

Raths prefer to hunt over scavenge, although they will readily feed on carrion should they stumble across it, deceased by either natural means (disease, age) or killed by another predator. Prey-theft is a common practice in opportunistic raths that are willing to raid from the kills of other predators, typically vipracanids (colloquially known as "dog-wyverns"). Raths generally subsist on ungulates including kelbis (Vernusecula maculata), erupes (Ovis alpina), burukkus (Bison longicaudatus), mosswines (Pachycephalochoiros phytosumbios), and bulldromes (Ossispina taurus); ornithischians such as aptonoths (Parasaurolophus cristatus), apceros (Ankylosaurus therianopla), rhenoplos (Monceratops petroides), and slagtoths; and theropods such as velocipreys (Dromos caeruleus), genpreys (Dromos dicornus), iopreys (Dromos rubinus), jaggis (Magnaraptor ebrius), and wroggis (Magnaraptor paluster). Raths that inhabit coastal areas or rainforests with brackish rivers will sometimes prey upon adolescent ludroths (Harpaga spp.) if the opportunity presents itself. Predatory attacks on humans, wyverians, and felynes are infrequent but not unheard of. The rath has a bite force of 1,400 PSI.

At least fifteen main hunting techniques have been documented, with many individual variations and the ability in most mature raths to readily vary back and forth between methods. Hunting strategies are largely influenced by the following factors: prey type, environment, the presence of a mate, and the presence of eggs/chicks. In regions with a high density of foliage (Schrade, Arcolis), raths rely less on fire-breathing for prey-capture, instead reserving fire-breathing for territorial exhibitions and fighting off intruders or potential hypercarnivorous predators. This moderation in their behavior is possibly done to avoid burning their source of starch and cellulose needed for microbial methanogenesis. In the Dede and Sekumaeya Deserts, and the Latio Volcanic Belt, however, raths have been observed doing the opposite. This discrepancy and the potential correlation between environment and fire-usage is still being researched.

Raths that live in xeric climates have a profound impact on fire regimes. The resulting fire ecology has shaped plant adaptations, and given rise to pyriscent species that release their seeds after fires (like the lodgepole pine), and resprouter species that can rapidly regrow after fires by activating dormant vegetative buds (like the eucalyptus).

When hunting by itself, a rath will rely on stealth tactics such as sudden swoops or dives from directly overhead, usually on a tailwind; this method is commonly known as the "high soar with glide attack." Another solitary hunting tactic is the "low flight with sustained grip attack," in which a rath will attempt to pierce vital organs, or cause shock via a crushing grip to bone and cartilage. When hunting in pairs, the raths will risk taking larger prey or assaulting herds. In the latter case, raths will initiate the hunt by circling overhead to instill panic. In the midst of the pandemonium, it becomes easier to discern the juvenile, old, or weak members of the herd from above. From there the rathian lands and attempts to isolate the target, distracting it with lunges as the rathalos flies in from behind. In turns the pair will slash and bite at their quarry until it's brought down; should the target prove too resilient for an immediate takedown, the rathalos and rathian will switch tactics and try to envenom it with the spines on their feet and tails. After envenomation, the raths will follow at a distance until their prey succumbs to a combination of the toxin and its wounds.

With smaller animals such as kelbis and juvenile vipracanids, raths will either land atop and proceed to asphyxiate their prey; or they will lodge their talons in the animal, fly a short distance with it, and drop them from a height. The drag-and-drop tactic is more commonly employed when a rath is hunting prey on cliffs and can easily pull the target over the edge with minimal exertion.

When a mated pair is brooding or raising chicks, raths will hunt in turns, never leaving the nest unguarded and at risk from ovivores. Raths supplement their diet with roughage, eating the fruits and leaves of various herbaceous and woody angiosperms. Digestion takes on average six hours, allowing raths to make use of large quantities of meat in a relatively short amount of time.

Enemies and competitors

Raths occupy the same ecological niche as other flying wyverns such as the seregios (Redimiculum echinatum), espinas (Barbarus punctus), berukyurosu (Fengzheng gaoyadian), and gurenzeburu (Barbarus campestris), and they compete for prey with pseudowyverns including the nargacuga (Xyrafiptera spp.) and tigrexes (Abinferno spp.). Raths will try to chase competitors out of their territory rather than let a potential rival of another species establish itself. Confrontations end when the intruder has been suitably injured and retreats. Conflict only goes so far as to intimidate or maim an opponent, with direct mortality virtually unheard of (although death from infected wounds isn't uncommon). Some studies have found the reverse, with raths largely ignoring other flying wyverns occupying adjacent or similar areas, possibly due to factors such as prey abundance.

Raths typically ignore vipracanids unless the raths are on a kill or are being harassed by the vipracanids, while the latter tend to visibly react to the presence of raths whether there is food or not. Raths will actively prey upon immature vipracanids or attempt to steal kills from a pack. On the Moga Archipelago, the reverse is sometimes seen, with the alpha jaggis (or great jaggi) coordinating attacks in order to force a rath off its kill. Other times jaggis will patiently wait from a distance of 5–13 meters until the rath finishes and leaves, but they're also bold enough to try and feed alongside the rath as well.

The deviljho (Daemon vorax), abiorugu (Heliosaurus ridens), seregios, and astalos are some of the only sympatric species that pose a high risk to raths. While a pair of raths may be able to injure a deviljho from the air with ranged fire-breathing, on the ground they're slower and not as agile, easily overwhelmed by the deviljho's pin attacks and lunges. The much-swifter deviljho can overtake a rath on the ground before it can become airborne and exert enough force with its jaws to tear off its wings or crush its trachea. When a deviljho is sighted wandering into a rath's territory, the rath will typically retreat to higher terrain where the deviljho has trouble traversing and wait for the danger to pass.

Attacks on people

People are not typically considered prey items by the common rath, although examination of defecated remains has revealed bones from human and wyverian victims. Studies by Guild biologists corroborate with eyewitness accounts from hunters, showing that 85% of the time, when a rath successfully killed a hunter, it didn't consume the body or take it back to its eyrie. The fact that most rath-hunter encounters are usually the result of provocation from the hunter (whether encroaching its territory, transporting eggs from its nest, or instigating it in combat) reaffirms the idea that raths aren't motivated by predatory intent, and fatalities are a result of territorial dispute and protection of offspring. Centuries of hunting raths has resulted in local populations acclimating to the presence of humans. Learned-fear aversion has helped condition raths to avoid human settlements and any interactions that would result in conflict.

Attacks on hunters are seen year-round with a peak in the breeding season, when increased hormone levels in the raths trigger aggression. The victims are usually burned from long-range fire attacks before the rath moves in, either to envenom them with its spines or to pin them under its talons while repeatedly biting the face. The rath's olfaction — while considerably weaker than its vision and audition — is still sensitive enough that having fecal matter thrown at its face will cause it to recoil, giving the hunter a chance to break free and escape.

Reproduction and life cycle

Most raths reach sexually maturity at six years of age. In the spring months, the rathian goes into a period of heat. Rathalos will enter the territory of the rathian and perform various acrobatic dives outside the rathian's eyrie, incorporating fire-breathing into the display as well. Rathians tend to select mates with the most vivid red scales and largest mandibular accessories. If the rathian takes interest in the courtship displays presented by her suitor, she will fly out to greet the rathalos. The final phase in the selection process at this point begins with the commencement of the prenuptial hunt. Together, the pair will stake out and kill prey within the rathian's territory, typically an animal no bigger than an aptonoth or a mature jaggi. The hunt is theorized to be an assessment of not only the rathalos, but of the pair's compatibility, and how coordinated their movements are. Cooperative hunting plays an important part in the lifestyle shift of the raths, a transition from independence to reliance on her mate to help kill larger prey. The successful outcome of these prenuptial hunt is the largest determinant in the rathian's mate selection; hunts that end in failure have an 89% chance of the rathian chasing the rathalos out of her territory with excessive force until a more suitable candidate arrives. Four months following copulation, the rathian lays a clutch of 3 to 5 amniotic eggs covered with a calcareous shell. The incubation period lasts around 52 to 61 days. The rathian and rathalos will alternate incubation in shifts while the other hunts.

The chicks, when they hatch, are entirely dependent on their parents for the first year of their lives. The parent raths will typically bring back small animals such as kelbis, vipracanids, and mosswine, and feed their offspring by presenting flesh held forward in their jaws. The young raths pick up and manipulate sticks, play tug of war with each other, practice holding things in their talons, and stretch and flap their wings. By twenty-two weeks, the chicks are strong enough to flap their wings, lift their feet off the ground, and rise up in the air. The offspring begin flying around twenty-seven weeks, and will begin learning to hunt by watching their parents. Juvenile raths disperse away from their parents at a year of age.

Communication

Although predominantly reclusive animals, the raths exhibit a range of social behavior amongst conspecifics. The most common tactile gestures between mates include brushing snouts together, entwining necks (necking), and mutual sunbathing. Snout rubbing — nuzzling one's face against the forehead, face, and neck of another rath — is believed to be a form of greeting that evolved from reciprocal grooming, because raths cannot reach these areas individually. The fact that raths will engage in fire-dousing, or lightly exhaling fire onto their mate to burn off ectoparasites embedded in their scales, supports its emergence through utility. Necking is often seen between mated raths after confrontation, and has been theorized to be a comforting gesture (though allegations of anthropomorphizing the behavior have lessened credibility somewhat). The evolutionary significance of necking is still being researched.

The rath's vocal repertoire is broad and complex; variations in intensity and pitch, in addition to discrete signals, play a large part in intraspecific communication. Rath sounds include bellowing, roaring, screeching, hissing, and snorting. In non-aggressive interactions the rath may make a deep, vibrating noise in the back of its throat akin to a growl.

HEALTH

Diseases and parasites

Raths are subject to ectoparasites such as ticks and mites, which burrow into the less thickly-plated underbelly or the skin around the nostrils. Severe infestation may cause problems with shedding, blood loss, decreased appetite, lethargy, and even death. Adult forms of several species of the tapeworm genus Taenia have been found within the intestines, the raths having ingested larval forms from aptonoth meat.

Raths are a major host for the feral wyvern virus in the Primal Forest, Ancestral Steppe, and Heaven's Mount. In raths, the incubation period is approximately 4 to 7 days, and results in the rath becoming highly aggressive, deserting its territory, and travelling up to 174 miles a day, thus increasing the risk of transmitting the virus to other animals.

DISTRIBUTION AND HABITAT

In Schrade, Arcolis, and Goldora, raths can be found in temperate deciduous forests on craggy slopes or peaks, preferring areas with overhangs to shelter themselves from rain and wind. In the same regions where rainforest and marshes are present, raths will build nests in areas with dry soil and enough vegetation to shield them from the precipitation. Raths of the Dede and Sekumaeya Deserts prefer a mixture of dry savanna forest and very dry deciduous scrub forest, clinging to the outskirts of the dunes. In the North and South Elde regions, raths making their homes along the volcanic belt will roost on the lower slopes and hunt in the sparse forests below.