The park is home to around 200 species of vetebrate, of which two thirds are birds. Mammals include the ermine, marmot, roe deer and chamoix. It is also worth noting the occasional presence of grizzly bears in the nearby valleys.

Birds are a very large and important group among the fauna of the park and the area has been declared and SPA (Special Protection Area for Birds) by the state. Of particular note are the black woodpecker, the capercaillie, Tengmalm's owl, the griffon vulture, the bearded vulture, golden eagle, wallcreeper (tichodroma muraria) and snow partridge.

Rare amphibians include the Pyrenean newt, the viper and the European smooth snake. Trout make their homes in the lakes whose cool, clean waters offer them a perfect habitat.