''Is Janas'' cave has unique features of its kind that develops as a 240 m long corridor. The cave opens with a rectangular entrance, sorrounded by a lush forest of holm oaks. It is a cave of karst formation, has a costant temperature of 14 degrees and a moisture wich reaches peaks of 100%. It is considerable important for the archeological finds in it and for the wildlife that stays in it, including this that we mention:
- the ''Speleomantes imperialis", a cave salamander endemic of Sardinia; - the ''Ovobathysciola gestroi" wich is part of the family of troglobites beetles (who live only inside the
caves); - the ''Autographa gamma'', an endemic Sardinian butterfly - the ''Rhynolophus ferrumequinum", the very common horseshoe bat.
Among the archeological finds there are remains of pottery shards and bowls forged and used during periods of Monte Claro culture in 3000 AC about