The Eurasian brown bear (Ursus arctos arctos) is one of the most common subspecies of the brown bear, and is found in much of Eurasia. It is also called the European brown bear, common brown bear, common bear, and colloquially by many other names. The genetic diversity of present-day brown bears (Ursus arctos) has been extensively studied over the years and appears to be geographically structured into five main clades based upon analysis of the mtDNA.