I've seen a bear still running in small circles in a 3.500m² compound in a zoo after being relocated there from another zoo (where they might have shot it). The reason for the circling (not enough space) was explained to us by the staff of the zoo. They said it'd wear off after a couple of months. Bear "Max" was 7 years old at the time (in 2000 or 2001). The 20 year old mother "Alma" was not running in circles. After the mother died in 2007, it seems the bear was held alone for 10 years. Max is still alive and with a partner now (Animal Park Olderdissen, Bielefeld, Germany).