Invertebrates are an important fauna group in the Serra de Tramuntana mountain range, with numerous endemic species, outstanding from among which we have the Timarcha balearica. This is a species of beetle which is black or metallic green, has no wings and is a herbivore. It is known locally as the monja or escarabat de sang (blood beetle), because it secretes a reddish substance when it feels threatened.

Of the 125 cave-dwelling invertebrate species on the island which only live in caves, 94 are found in cavities in the Serra de Tramuntana.