While bear activity is high in the warm summer months, bear movement seems to slow down before the start of winter. Bears in November generally tend to stock pile on food (about 90 pounds of food each day) to get them through the harsh winter months when natural resources are scarce. In December, the cubs will sleep a great amount while the adults forage for food.
Bears will tend to seek sanctuary in bear dens to survive the chilly winter months. Bears really don't go into "hibernation" mode, when we think they sleep through the winter; but instead, go through "walking hibernation." This means that their metabolism slows down, including their heart rate (low as 8 beats per minute); but they continue to scout for food, burning about 4000 calories each day.
While bear movement may slow down in the wintertime, gardeners must still keep bears away from gardens with the most effective types of bear fence: electric fence or a sturdy livestock fence made from woven wire.