The high species diversity of plant communities in the four altitudinal belts and in the azonal habitats of the cirques is decisive for the composition of the fauna. The current animal communities have successively developed in the course of about 12,000 years since the last Ice Age. Lower mountain elevations are characterized by typical Euro-Siberian species from the broad-leaved forest belt. Elevations above 800 m belong to the Variscan zoogeographic province (taiga belt), with an increasing number of genuine mountain species living at higher altitudes. The well-developed subalpine belt and the alpine belt of the summits provide suitable habitats for many cold-preferring northern species. The occurrence of these glacial relics derives from the geographic situation of the Krkonoše Mountains and local conditions during glaciation.
Four big species of beasts of prey were extirpated from the mountain forests by people during last few centuries - the bear, lynx, wolf and wild cat. Commonly found animals are now deer and red-deer, badger, fox, marten and in the lower locations plenty of boars. However, the most frequent fauna are birds - e.g. Chaffink, Crossbill, Siskin, Nutcracker, Black Woodpecker and some big tit species, rarely the Black Stork, among the birds of prey can be counted the Common Buzzard, Goshawk, Sparrow Hawk, and even rarely Lesser Spotted Eagle. Among the owl family we can spot the Tawny Owl, Long-cared Owl, and Tengmalm's Owl. Among the invertebrates there are frequently species of satyr butterflies and brushfooted butterflies, ground beetle (Carabus silvestris), Violet Ground beetle and Golden ground beetle (Carabus auronitens), one of the biggest European weevils (Liparus glabrirostris), and longhorned beetles or longicorn beetles.
There are quite different fauna to be found in the dwarf pine stands, on the mountain meadows and subarctic peatbogs. The Water and Meadow Pipit represent birds and in the past the glacial relic Dotterel was frequent here along with the minute bird of prey Merlin. On the contrary, in the last decade the Bluethrot and Redpoll have been occurring in greater numbers here. As far as mammals are concerned, the glacial relic alpine shrew lives in the mountain meadows, now and then you can see a lizard or a wiper that can even rarely occur in its black form.
The stony places and block screes are home for the Black Redstart, Wheatear and Kestrel, and even rarely for Alpine Accentor. They say in Kotelní jámy a beautifully colored Rock Thrush makes its home. Malá Sněžná jáma is a well-known locality of the glacial relic whorl snail (Vertigo arctica) and of Gyllenhal Ground Beetle (Nebria gyllenhali). Dippers, White and Grey Wagtails and Kingfishers live in the vicinity of the mountain brooks. Due to the strong acidity and chemical changes to the running water (imissions) trout have been lost from many of Krkonoše' mountain brooks.
On the surface of snow cover some organisms, especially insects have found their home, for example: Snow Flea, and some stonefly species. The dark coloring of the snow surface need not always be caused by dust, needle-leaves or bark fragments, but also by the accumulation of minute springtails that also belong the the group of chionophilous animals. The occasional green, yellow or red coloring of firn snow cover is the work of some chionophilous algae.
In comparison to the nearest Central European mountains, the proportion of glacial relics in the fauna of Krkonoše is high. Relic invertebrates include the arctic whorl snail (Vertigo arctica), Sudetic wolf spider (Acantholycosa norvegica sudetica), dragonflies (Somatochlora alpestris, Aeschna coerulea), mayfly (Ameletus inopinatus), ground beetles (Nebria gyllenhali, Amara erratica), and several geographically isolated species of butterflies, beetles, two-winged flies and water mites. Relic vertebrates include ring ouzel (Turdus torquatus), redpoll (Carduelis flammea), red-spotted bluethroat (Luscinia svecica svecica), dotterel (Eudromias morinellus) and field vole (Microtus agrestis) which is currently dominant in the stands affected by air pollution. The wealth of the Giant Mountains’ fauna is still unknown in many fields, especially in the group of invertebrates and the further intensive zoologic research promises many more surprises