- Order: Saurischia
- Suborder: Bird Feet
- Infraorder: Bird Wyvern
- Superfamily: Eared Bird Wyvern
- Family: Garuga
Within the Old World Yian Garuga have only been observed so far in the Jungle, Gorge, Great Forest, Everwood, Volcano, Volcanic Hollow, Jurassic Frontier, Esther Lake, Swamp, Ancestral Tomb, Forest and Hills, and the Ruined Ridge nesting high in mountain caves.
There is an old saying among some regions: "If a Yian Kut-Ku can live in this area, than a Yian Garuga can't be to far away from this area."
Yian Garuga hunt almost exclusively at night, using its deadly poison or stabbing its prey with its sharp beak to finish off its victim. If hunting another predatory species such as a Velocidrome, Yian Garuga will first stun the creature with its roar before launching any attacks. Rathalos, Rathian, Abiorugu, Tigrex, Espinas Subspecies, Dyuragaua, Berukyurosu, Nargacuga, Seregios and the rare Rajang are fierce competitors of the Bird Wyverns and are even capable of killing them if an opportunity were to arise. However, being one of if not the most feared member of the Bird Wyvern class these creatures are fully capable of defending themselves against potential threats.
The average size of an adult Yian Garuga is approximately 1395.6cm. Yian Garuga possesses keen night vision and is aided in its night time hunts by its dark purple shell, making the creature very hard to spot from below. Yian Garuga is far more proficient in lobbing fireballs than its cousin, Yian Kut-Ku. It is nimble enough to perform backflips, whipping its foe hard with its spiked and poisonous tail. Yian Garuga has large ears, just like the Yian Kut-Ku. The ears assist in hearing its prey from great distances. Yian Garuga's beak and shell are especially hard for a Bird Wyvern, throwing some inexperienced hunters off guard as they are too accustomed to the much weaker Yian Kut-Ku. One of its most peculiar adaptations is its remarkable intelligence. One example is its ability to avoid certain traps. It is also much better at linking and more effectively using its attacks to disable the unwary hunter. Like their relatives, the Kut-Ku these creatures also have shovel-shaped beaks that are capable shoveling up smaller prey.
Some rare individuals possibly old Garuga have more developed and extra spikes on the shell and tail along with increased poison abilities such as being able to eject a poison mist from their tail spikes, and some are able to spit poison from their mouths.
In the Val Habar region, Yian Garuga have four toes, while their other counterparts have only three.
Very war-like in nature, Yian Garuga are a monster that is best avoided. Yian Garuga are very solitary creatures though, they have rarely been seen in groups possibly during a mating season, the groups consisting of more than two have been seen on islands. After mating, a female will sometimes seek out a Yian Kut-Ku nest, destroy the eggs, and then lay its own eggs in the nest for the oblivious Kut-Ku to raise and care for. This shows that a female Garuga can be a Brood Parasite like a real-world cuckoo bird. Yian Garuga perform this behavior due to their poor parental behavior.