Bears walk on the soles of their soft feet, so they often do not leave distinct tracks unless they walk through soft mud or snow. 

Bears have 5 toes on each foot.  Their large toe is on the outside of the foot and the small inner toe does not always register. 

People are always surprised to find that black bear scats do not have an unpleasant smell if the bears ate only fruit, nuts, acorns, or vegetation.  In those cases, the scats smell like a slightly fermented version of whatever the bear ate.  Distinctive smells like strawberries come through clearly.  Scats that contain meat or garbage smell somewhat foul but nothing like the feces of dogs, cats, or primates. 

Black bears of all ages and both sexes rub their scent on marking trees, including wooden sign posts and utility poles, but the majority of this marking is by mature males during the mating season (May and June in Minnesota).  They rub their shoulders, neck and crown and may also claw and bite the tree.  Claw marks are usually superficial, but incisor bites are deep enough that pieces of bark and wood are sometimes pulled out.  Bites leave nearly horizontal marks that look like a dot and a dash where the upper and lower canine teeth came together.