The fauna of Europe is all the animals living in Europe and its surrounding seas and islands. Europe is the western part of the Palearctic realm (which in turn is part of the Holarctic). Lying within the temperate region, (north of the equator) the wildlife is not as rich as in the hottest regions, but is nevertheless diverse due to the variety of habitats and the faunal richness of Eurasia as a whole.
Before the arrival of humans European fauna was more diverse and widespread than today. The European megafauna of today is much reduced from its former numbers. The Holocene extinction drastically reduced numbers and distribution of megafauna and continues to (such as with wolves and bears). Many of these species still exist in smaller numbers, while others thrive in the developed continent free from natural predators, with the former threatened by human activity (particularly megafaunal species).