The habitat used preferentially the bears released and which currently form the Pyrenean population in Catalonia are fir forests, black and red pine, beech, hazel and oak, these forests alternating with meadows and alpine scrub, subalpine and montane. Although they may cross the bottom of valleys and high ridges in their displacements, altitude for which often move is 1,400 to 1,800 meters above sea level. During hibernation usually settle in rugged and difficult access areas where peace and security are necessary.

Although the brown bear is of the order of Carnivores, is an opportunistic omnivore; their diet changes according to the seasons: herbs, buds, dry fruits (acorns, beech, chestnut), fleshy fruits (blueberries, cranberries, apples, cherries), insects, honey, dead animals, domestic and wild mammals. As an annual average, more than 75% of their diet is vegetable matter.

Since four years they can reproduce, although females in the Pyrenees that have been pregnant at 2.5 years and at 3 years have had cubs. Between May and July zeal and copulations occurs.

After a period of delayed implantation, ovum begins to develop from October, and the puppies (between 1 and 3), are born in late January.

Bears hibernate from December to March, within a cave. Their physiological function (heart rate and respiratory rate) were at a slower pace, but is not a true hibernation, for example, as would be the case of marmot.