John Irving 
Setting Free The Bears [EPUB ebook] 

’The brown bears paced, brushing their thick coats against the bars; their heads swayed low to the ground, in rhythm with some ritual of stealth they were born knowing and pointlessly never forgot’It is 1967 and two Viennese university students decide to liberate the Vienna Zoo, as was done after World War II. The eccentric duo, Graff and Siggy, embark on an adventure-filled motorbike tour of Austria as they prepare for "the great zoo bust." But their grand scheme will have both comic and gruesome consequences, as they are soon to find out…