The bears of the Pyrenees begin the winter inside hibernation caves, using their forces accumulated during the autumn months. The vegetation of the Aran Valley and the Pallars has facilitated good nutrition for all family members (especially for the harvest of acorn’s oak) and now they may rest for a few months using accumulated fat.
The males are the last in the cave and the first ones out; the females without puppies follow them, females with first year cubs and eventually the pregnant females.
If all goes well, the pregnant females give birth to between one and three puppies in late January. At birth, the cubs of brown bears weigh between 350 and 500 grams and remain in the cave until April, feeding exclusively on breast milk, very rich in fat.
One of the automatic cameras installed in the Natural Park of the High Pyrenees in collaboration with the PirosLife Project has allowed capturing images of a female with a first year puppy few days before they entered the cave where they will spend this winter.