We’re on the hunt for brown bear dens in Poland’s Carpathian mountains, on the border with Ukraine. The lairs lie within the gnarled caverns that naturally form at the base of decaying fir trees when they get to about 130 years old. Each den is slightly different – some have rocky bottoms, others have been lined with beech leaves, making a sort of woodland mattress. Looking inside gives an insight into the character of each bear, just like visiting a friend’s house.