Ever heard a squirrel growl? Squirrels growl because they are shy animals and prefer to stay away from humans. When humans enter their territory, invade their space, threaten their young or disturb them, it creates stress and they feel threatened. This type of growl is more of a warning sign than a threat, but it’s best not to provoke a stressed squirrel making growling or barking sounds. If one is making aggressive gestures (such as raising its tail high), slowly back away until there is enough