The Fanghur were native animals of the Beor Mountains, and they were commonly known as wind-vipers.
Fanghur resembled giant serpents around twenty feet in length, with leathery wings similar to those of dragons, but smaller, could not breathe fire, and were less intelligent than dragons. They had dappled green or brown scales. They stunned their prey with an immobilizing mental screech and then killed them. They usually hunted in groups of three or four. Dragons and Fanghur are distant cousins, but are less closely related than Dragons and Nïdhwal.
The Fanghur were extremely endangered during Eragon's time. When traveling from Tarnag to the Âz Ragni, Eragon and Saphira were attacked by a group of three Fanghur, but thanks to Saphira's strength and fire, the Fanghur were scared off, with one being injured. Arya then commented that they would be sorely missed if Saphira had killed them, implying they were highly endangered. The Dwarf clan known as the Dûrgrimst Fanghur (led by Grimstborith Havard at the time of the Rider War) were named after them.