Look to the teeth. Knowing what your mystery animal ate is key to a positive identification. Insectivores have sharp-pointed molars. The molars of omnivores are flat, and their canine teeth are smaller.
Carnivores have teeth somewhat like our own; their incisors help penetrate and keep a grip on food, molars crush and grind food, but their canine teeth are much larger, wider or longer. These teeth can be used to attack prey or for self-defense.
Tooth formations can vary among subfamilies and subspecies. For example, each type of bear may have a slightly different diet, requiring smaller, larger or flatter molars and greater or lesser canines.