The brown bear (Ursus arctos) appeared 35 million years ago. It lived almost throughout Europe up to the 15th C., but after the 19th C. its population was reduced dramatically, due to hunters and the destruction of its natural habitat. Today the brown bear is considered -legally now- to be a species threatened by extinction in Western, Central and Southern Europe. It is characteristic that their total number in France, Italy and Spain does not exceed 200.

It is estimated that in Greece there are around 150 brown bears that have formed two small populations in the most remote regions in the Pindos and Rodopis Mountain Ranges, which now constitute the largest in number populations in the Member-States of the European Union.

In 1994, WWF Hellas, in conjunction with ΑRCTUROS and the Hellenic Society for the Protection of Nature, began the ARCTOS Program, under the auspices of the Ministry of Agriculture and with co-financing by the European Union. Its objective is to preserve a viable population of brown bears in Greece, ensure the communication of its sub-populations in a wider geographical area and a final solution to the problem of the illegal possession and exploitation of the species.