Gravios Ecology

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

In-Game Information
A large wyvern found in volcanic zones. They have a fire breath attack and the ability to emit a sleeping gas and explosive gas attack when in rage mode. They also have extremely hard scales that deflect most weapon attacks.

Taxonomy
A true wyvern, the Gravios and its black counterpart belong to a sub category known as the "Rock Wyverns" and although they can still lift their weight with their wings, they cannot fly for very long. Rock Wyverns are very large, and generally stick to volcanic or mountainous regions due to their diet of ores. Some theorize that the Gravios will eventually evolve into a fully terrestrial wyvern.

Habitat Range
The Gravios is found in the Swamps and Volcanos.

Ecological Niche
Among the largest of the true wyverns. Gravios out-weighs its brethren, but can still lift its bulk using its wings. Gravios are identified by their sheer size, armoured shells, and their diet of ores and minerals.

Gravios is easily one of the strongest wyverns found in either the swamp or volcanic regions. They feed heavily on volcanic rocks for minerals and ores, which consequently aid the development of their supremely strong shells. Gravios are known to migrate to the Swamps, and considering the concentration of ores found in the cold caves, it can be assumed that they can sustain themselves here, too. Based on it's diet of ores and minerals, it would not be featured on the food chain, unless preyed upon and killed, but that is very rare. The bulk of the Gravios is enough to discourage predation, as is its habits to travel using the lava systems of the Volcano. However, this could lead it to be preyed upon by the similarly large Lavasioth. There have also been sightings of Akantor attacking and killing Gravios.

Biological Adaptations
Thick, durable rock-like body armor shields Gravios from intense volcanic heat. Its shovel-like head assists when feeding on hard rocky surfaces and in tunneling. Its stout legs support its great weight and a thick, its club-like tail helps balance the creature and is useful in self defense. Gaps in the Gravios' underside expel two kinds of gases. The first is a knockout gas, one potent enough to put many monsters to sleep, that is produced inside the Gravios' body.Gravios no longer do the poison gas because their poison is mixed with tranquilizing chemical so it became purely sleeping gas. The second is a flammable gas it expels as a waste product of its 'heat beam', and of its diet. Since the Gravios feeds on rocks and minerals, there is the possibility of some combustible minerals will remain in its mouth which will allow it to use its 'heat beam' attack. Gravios can also submerge and "swim" through lava channels for a while, suggesting that it has big lungs to hold its breath for a long time, and that it's eyes are protected by a special membrane while in the lava (or possibly just closing them the whole time).

Behavior
Relatively docile until provoked, but like most wyverns are fiercely territorial. The Gravios inhabits large areas of the Volcano, where it is sufficiently large enough to incubate and raise its juvenile Basarios. It is surprisingly passive to most other inhabitants of this area, but considering its near-impervious shell, it is probably just not bothered by it. Further, its eggs are large and strong enough to sufficiently discourage attack, whilst the mother wanders in search of nutrition. Sometimes it retreats into the lava to escape from predators.