The fauna is just as diverse as the flora. The park is home to mammals such as the brown bear, red deer, roe deer, chamois, wild boar, wolf, pine marten, stone marten, badger, weasel, squirrel and dormouse. The most important animal used to be the lynx, after which Risnjak got its name. The lynx was exterminated during the 19th century but returned to Risnjak three decades ago, after a successful reintroduction project in neighboring Slovenia. There are also numerous bird species living in Risnjak: capercaillie, hazel grouse, goshawk, eagle owl and several woodpecker species, amongst others. A number of amphibians and reptiles, as well as various insect and snail taxa can also be found.