Over the centuries wolves evolved an elaborate system of body language, facial expressions, and vocalizations to communicate with each other. Domestic dogs also use this means of communication, and all of these signals are easily understood by other dogs. If you can learn to interpret how your dog is feeling by observing its posture and expression and listening to it, you'll be well on the way to successful communication with your pet and better equipped to solve any behavior problems that arise.Following are some major canine attitudes and their typical outward manifestations.
AGGRESSIVE
	Ears	Forward or back, close to head.
	Eyes	Narrow or staring challengingly.
	Mouth/ Teeth	Lips open, drawn back to expose teeth bared in a snarl. Possible jaw snapping.
	Body	Tense. Upright. Hackles on neck up. Completely Dominant position.
	Tail	Straight out from body. Fluffed up.
	Vocali- zation	Snarl. Growl. Loud bark.
ALERT
	Ears	Perked-up. Turning to catch sounds.
	Eyes	Open normally or wide.
	Mouth/ Teeth	Mouth closed or slightly open with teeth covered.
	Body	Normal. Possibly standing on tiptoe. Slightly Dominant position.
	Tail	Up. Possibly wagging.
	Vocali- zation	None. Low whine or alarm bark.