The fauna of the Park is extremely rich and varied. Until a few decades ago predators such as the wolf, the brown bear, the lynx, the vulture, the golden eagle, but also herbivores such as the ibex, the red deer, the roe deer or rodents such as the marmot had practically disappeared from the Park. Thanks to the protection offered by the Park and to specific projects of wildlife reintroduction, the Park again resounds with the whistles of alarm of the marmot in the meadows at high altitude, the populations of red deer, roe deer and chamois are consistent, there are frequent flights of the golden eagle, and there is a stable presence of tetraonidae such as the black grouse, the capercaillie and the ptarmigan. Large carnivores are now returning stably in the Park: in particular in 2016 there were the first sightings of the wolf, and now some specimens of this species is frequenting the territory.
Among the mammals, surely the most conspicuous of the protected area are the ungulates; among these, in addition to the deer, we find the roe deer, well distributed throughout the territory of the Park, but with lower density in the past also due to the increase of the population of deer, who are experiencing a moment of great dynamism: from the few exemplars that fortuitously escaped from the fence of Paneveggio in 1963 there is now a population that gravitates in the catchment areas of the Cismon, the Travignolo and the Vanoi that abundantly exceeds 1,500 specimens. The chamois is also well represented, even if an epidemic of mange has reduced its number in recent years. The ibex, reintroduced in 2000 by the Park, has constituted a colony in the eastern portion of the Pale di San Martino; its constant numeric growth has also in recent years been affected by the epidemic of mange.
Among other vertebrates there are very many mammals and birds that are typical of the mountain environment. Among them stand out the capercaillie (Tetrao urogallus), the largest among the alpine galliforme birds and the black grouse or wood grouse (Tetrao tetrix). The ptarmigan (Lagopus muta) lives at higher altitudes, in the alpine prairies, while the hazel grouse (Bonasa bonasia), is the forest tetraonide par excellence. The eagle owl (Bubo bubo), together with the golden eagle (Aquila chrysaetos) are the only winged apex predators present in the territory of the Park. Between the woodpeckers present, with six species found, we remember the rare three-toed woodpecker (Picoides tridactylus, the presence of which was discovered in the territory of the park only a few years ago. Among the other components of the avifauna worth mentioning is the rare wallcreeper woodpecker (Tichodroma muraria), frequenter of the rocky walls at high altitude; a particular mention should be made of the presence, as nesting species, of the corncrake (Crex crex), that frequents the meadow areas of the Park. Recent research carried out in the territory of the Park has established that during the reproduction period there are at least 84 species of birds.
Among the amphibians, surely the most interesting species is the Alpine salamander (Salamandra atra); considered rare until a few years ago, one can encounter it with relative ease in the detrital environments and in the high-altitude forests of the dolomitic mountains of the Park. Water courses are populated by trout (Salmo trutta fario), while in the high-altitude lakes there is the presence of Arctic charr (Salvelinus alpinus) and of the minnow (Phoxinus phoxinus). Among the invertebrates, the Lepidoptera papilionoidei represent the most observable component, consisting of about a hundred species. Some of these are extremely rare, such as, for example, the parnassius apollo (Parnassius apollo).