Dogs cannot literally sense 'evil,' but they can detect unusual behavior, scents, and emotional cues, which may make them react unusually in certain situations.
Dogs have heightened senses, and while there's no scientific proof they see spirits, their behavior can change in ways some interpret as spiritual sensitivity.
Dogs may display unusual behavior such as barking at nothing, staring into empty spaces, or reacting fearfully without reason, which some interpret as sensing spirits.