Romanian brown bears can weigh up to 400 kilograms - that's about as much as five grown-ups put together. But despite their size, they are wonderfully fast. A bear can run at 50 km/h for a short burst - faster than the cars on most country roads.
Bears spend the summer eating as much as they possibly can - berries, roots, mushrooms, fish, insects, honey if they can find a beehive, and the occasional bigger meal. They have to put on a thick layer of fat because in winter, when there's no food in the snowy forest, they tuck themselves into a den and sleep for around five months.
While they sleep, female bears sometimes give birth to one or two tiny cubs - so small at first they would fit in your hands. The cubs stay snuggled up against their mum until spring, drinking her milk. When the snow melts, the family comes out together.
Bears and people share these mountains, and Romanians have lived alongside them for thousands of years. Forest rangers track the bears and look after their habitat. Hikers are taught to make noise as they walk so bears can hear them and quietly move away - bears almost always want to avoid people, not meet them.