On the Giara, there is an important variety of animal species. Forests of cork and oak alternate with Mediterranean maquis, garrigues, prairies, and ponds to make this plateau a rich fauna shelter, in which the most famous specimen is the Giara horse. These wild horses of medium height (no more than 120 centimeters at the withers) are not a native breed, but they have been on the plateau since time immemorial. Their coat is bay, shiny, and reaches very dark shades. Their long and thick manes and their agile bodies give these animals surprising beauty and grace. The small herds graze freely in the company of cattle, goats, and pigs, drinking from the numerous ponds. On the plateau, there are currently about 700 horses. Some of them are privately owned, whereas the rest of them belong to the Equestrian Institute of Ozieri, which has been engaged for years in the defense of this breed. The Giara horses are a priceless heritage and an absolute rarity, as this is the last colony of wild horses in Europe.
The fauna of the Giara includes some of the most common species of mammals that are normally present in the woodlands of Sardinia: wild boars, foxes, martens, wild rabbits, hares, and hedgehogs. Besides these, it is worth mentioning the many species of permanent birds, such as Sardinian partridges, sparrowhawks, and peregrine falcons, and a large number of migratory birds, both terrestrial (thrushes, blackbirds, woodcocks, wood pigeons) and aquatic (herons, ducks, snipes, marsh harriers). Nesting species include hawfinches, mistle thrushes, woodlarks, shrikes, black buntings, Dartford warblers, great spotted woodpeckers, jays, and bee-eaters.
The rich and interesting ecosystem of the paùlis is home to grass snakes, frogs, toads, leeches, dragonflies, beetles, and two archaic species of crustaceans, Lepidurus apus lubbocki and Triops cancriformis, which have remained unchanged for 200 million years.