The characteristic island vegetation and karst terrain condition a poor fauna of the mainland area. According to available data, this area is home of more than 490 animal species. Many of them are endangered species protected by the Nature Protection Act of the Republic of Croatia.
The most numerous animal group are invertebrate with 339 recorded species. According to the present data, these are mostly representatives of arthropods. Knowledge of the fauna of terrestrial habitats mostly stems from earlier research (1925). After that individuals conducted sporadical research, but only recently has the re-investigation of certain groups been initiated.
Recent research of beetles (Coleoptera) in the Nature Park has shown that the community of ground beetles (Carabidae), longhorn beetles (Cerambycidae), and the dung beetle (Scarabaeidae) is rather poor in species. Amongst ground beetles, the most numerous species are from the family Harpalinae whose diet and lifestyle is connected to fields, meadows and vineyards. Two recorded representative species of the ground beetle family (Carabidae), Laemostenu sdalmatinus and Molops dalmatinus, are endemic species associated with karst areas.
According to the Red Book of Endangered Diurnal Butterflies of Croatia, for protected species of diurnal butterflies are present in the Nature Park: Lulworth skipper (Thymelicus acteon), green-underside blue (Glaucopsyche alexis), swallowtail (Papilio machaon), and cabbage white butterfly (Pieris brassicae).
More recent studies of terrestrial malacofauna established 37 species of land snails. Thus, 14 previously recorded species were confirmed, and 23 other species were discovered in the Nature Park. The fauna is dominated by the stenoendemic species Delima edmibrani and species Agathylla lamellosa, with the Nature Park as its northernmost habitat. Both species can be found in rocky habitats of the steep slope where they are threatened by potential visitors (walking, leaning on the ground, and destroying the snails). Other special species are the endemic species Chondrina spelta ventilatoris, with its westernmost habitat in the Nature Park, and rare species of Croatian fauna – Paralaoma caputspinule and Testacella scutulum.
The fauna includes a relatively high number of endemic species of a smaller or larger part of the eastern Adriatic coast. Beside the above mentioned, the species include Cochlostoma scalarinum scalarinum, Hypnophyla pupaeformis, Delima albocincta albocincta, D. bilabiata alschingeri,Poiretia cornea, Helicigona setosa, indicating its uniqueness and the need for protection of the entire fauna.
Different species of vertebrates have been recorded in the Nature Park, and most of the data originates from 1930, but have been supplemented by further research, especially by the Association of Biology Students – BIUS in 2000.
The class of mammals is the least represented class. Some of them, like the house mouse (Mus musculus), brown rat (Ratus norvegicus) and wildcat (Felis silvestris), are linked to the presence of humans. Of natural fauna, the common vole (Microtus arvalis) and beech marten (Mustela foina) are still present. The European hare (Lepus europaeus) used to live on the island, but it most likely became extinct due to a large number of martens and the use of pesticides in agriculture on the island.
In Telašćica area there are nine species of bats, including some endangered and vulnerable species. The largest so far determined colony in the Park area is in cave Golubinka with a sea entrance under a cliff, which is inhabited by around 2000 Geoffroy’s bats (Myotis emarginatus) and around 1000 greater horseshoe bats (Rhinolophus ferrumequinum). Fairly large concentrations of other species, such as the European free-tailed bat (Tadarida teniotis) and grey long-eared bat (Plecotus austriacus) were found.
Birds account for the largest number of mainland vertebrates; 115 species of birds have been registered so far. They find good nesting and temporary habitat conditions on different locations. Vertical, steep cliffs are an ideal place for forming colonies of all three species of swifts that live in Croatia. The pallid swift (Apus pallidus) is a dominant species which nests in cliff cracks, sometimes in larger colonies with the common swift (Apus apus), while the alpine swift (Tachymarptis melba) nests individually. Due to the neglecting of agricultural areas and intense usage of pesticides, the bulk of food for the swifts and insects has shrunk, leading to a decrease in the number of these birds.
Amongst bird fauna, raptors are particularly interesting. 15 species of raptors have been observed in the Park, at least five of them are nesting birds. The peregrine falcon (Falco peregrinus), an endangered and increasingly rare species, nests on the outer island cliffs. Apart from the peregrine falcon, here it is possible to see the Eleonora’s falcon (Falco eleonorae), which behaves as a nomad in this area and nests on southern open sea islands, the lanner falcon (Falco biarmicus) and the merlin (Falco columbarius), as well as nesting birds: the common kestrel (Falco tinnunculus), the short-toed snake eagle (Circaetus gallicus), the Eurasian sparrowhawk (Accipiter nisus) and the common buzzard (Buteo buteo).
The European shag (Phalacrocorax aristotelis) nests on low covered ledges and in niches by the sea on cliff crowns on the open sea side of the Park. The common raven (Corvus corax) is frequent, too. It often chooses rocks and cliffs for nesting, and feeds in open habitats. The Caspian gull (Larus cachinnans) is probably the most noticeable species of birds. It is a sedentary bird which nests in small colonies along the Park coast. In karst areas it is possible to see the Eurasian eagle-owl (Bubo bubo), an increasingly endangered European owl. Common songbirds in the area are the black-eared wheatear (Oenanthe hispanica), the rock partridge (Alectoris graeca) and the common rock thrush (Monticola saxatilis). The most common nesting birds in garrigue and maquis are the Sardinian warbler and the subalpine warbler (Sylvia melanocephala and S. cantillans). During the spring and autumn migration, a large number of European migratory birds fly over the Park, and of wintering birds it is possible to observe different kinds of ducks.
The presence of amphibians is conditioned mainly by water, and since this area is relatively dry, only two species tolerate the dry conditions and inhabit the Park: the European tree frog (Hyla arborea) and the European green toad (Bufo viridis). The European tree frog can mostly be found in puddles, which are mainly periodic, so this species, which is narrowly tied to water, had to partly alter its way of life. It is necessary to conduct research on the species life cycle in such extreme conditions. Particular attention should be given to the preservation of puddles as a special type of habitat.
The reptile fauna is more numerous and consists of 13 species: 3 species of turtles, 4 species of lizards and 6 species of snakes. Of the very endangered species, it is necessary to mention the loggerhead sea turtle (Caretta caretta). In houses it is common to see the Mediterranean house gecko (Hemidactylus turcicus), which is a very nocturnal animal. However, it is even more common to see the Dalmatian wall lizard and the Italian wall lizard (Podarcis melisellensis i Podarcis sicula). The Italian wall lizard is the most common species of lizards which mostly inhabits karst areas covered with low shrubland and drystone walls. Sheltopusik (Ophisaurus apodus) is also common. It inhabits all areas of the Park, but is more frequent in fields rich with puddles and wells.
Six species of snakes have so far been found on Dugi otok: the European ratsnake (Elaphe situla), the European cat snake (Telescopus fallax), the Balkan whip snake (Coluber gemonensis), the Montpellier snake (Malpolon monspessulanus) and the grass snake (Natrix natrix). None of them is venomous to humans. It can be assumed that the four-lined snake (Elaphe quadro lineata) can be found in the Park, since it has been spotted on the northern side of Dugi otok on several occasions. Biologically the most interesting finding of reptiles on Dugi otok is the European blind snake Typhlopsvermicularis. That is an extremely rare underground species registered only once in Croatia, near the town of Sali in 1977.
Invertebrates of the Nature Park Telašćica, its mainland part, are only beginning to be explored. In the research done so far, 339 species of invertebrates were discovered: 58 species of butterflies (diurnal and nocturnal), and species of 16 odonates. Of other invertebrates, 65 species of mainland molluscs, 39 species of beetles, 20 species of Homoptera insects, 65 species of Heteroptera insects, 16 species of centipedes (Myriapoda), 53 species of spiders (Aranea), 1 species of harvestmen (Opiliones), 2 species of scorpions (Scorpiones) and 4 species of false scorpions (Pseudoscorpiones) were found.
Of mainland invertebrates, in the summer it is common to hear crickets which live on pine trees and produce characteristic sounds throughout the day. In the early summer and spring, it is possible to notice various butterflies, with the yellow Cleopatra butterfly (Gonepteryx cleopatra) being the most common.