The Silver Rathalos is an extremely rare genetic mutation of the Rathalos.
He can be found mainly in the Towers along with unexplored parts of Fonron though they will leave the Towers to hunt in other areas such as the Old Swamp and Misty Peaks.
Just like Azure Rathalos, his fighting skills are more advanced most likely from his color or possibly part of his genetics. His power is actually close to those of Elder Dragons.
Silver Rathalos seems to prefer living in areas not to warm from his hide being able to absorb heat very quickly.
The Rath's talons from older Los' wings are able to rend boulders like paper.
Rath's marrow ignites on air contact. The Silver Rathalos and the Gold Rathian produce a liquid much more powerful than the marrow that even glows faintly in the dark.
Silver Rathalos parts actually glow even in pure darkness like the shell and scales.
All three HC Rathalos seem to be old individuals with advanced firepower and fighting skills.
There are two Subspecies of Rathalos, the Old World Rathalos and the New World Rathalos.
Its believed that the Rathalos in Val Habar might be a 3rd Subspecies of them.
Why is it an Elder Dragon-Level Monster?
Rare Species are about as rare as Elder Dragons. Some Rare Species even have some abilities that is on par with Elder Dragons. It has even been found that some Rare Species use the Dragon Element like Elder Dragons, though isn't really noticeable most of the time.
Tower Summit BGM
MHFU/MH4U/MHF-G9: Tower Music Theme (HR1-99)
【MH4G】G★3 リオレウス希少種 - 太刀で翼打撃 - 練習中 - by Efenbaum 崔宰源