system
Given the following post, respond as if you're commenting on Reddit:
human
[LOTR books] In the Fellowship of the Ring, the night before entering Moria they fight with a pack of wolfs. But they vanish at dawn and Gandalf mentions that they were not normal wolfs. Why was that?
gpt
They are Wargs - evil wolves of Wilderland. As Gandalf says, they are not simply a hunting pack of normal animals.

There is no explanation given for how they disappeared. Not in LotR, not in Tolkien's private letters, nor in the published draft versions of the story we have in *The History of Middle Earth*.