Source: Liz Stelow

Dogs can display a variety of behaviors when they are stressed or a little frightened. Some are very obvious: shaking, cowering, running away, or whining. But, some may appear to be normal behaviors that just shouldn’t be happening in that moment. Following are some of those behaviors:

Hiding

Even if your dog prefers “den-like” resting places, you may finding him hiding at odd times, like when you get out the leash to go for a walk or when you run the water in the bathtub. In those situations, your dog is not looking for a resting place—even if the place he chose is a cherished resting place like his crate or corner of the sofa. He is hiding so as not to be involved in whatever comes next. The look on his face is likely to tell you he is not happy.

The problem is, if you attempt to get your dog out of hiding while the “threat” is still present, he may become aggressive toward you in an attempt to maintain his hiding status. Such an attempt will likely increase his , as well. Because hiding is an extreme form of saying “no,” you will likely have to give up on the intended activity until you have a chance to help your dog find it less .

Messages using the eyes

You probably do something to your dog that he doesn't like. Often this would include nail trimming or tooth brushing. Next time you walk into your living room with the dreaded nail clippers or toothpaste, look at your dog to see his reaction. Focus especially on his eyes. If his pupils are dilated, he is stressed. If you can see the whites of his eyes to one side, he is stressed; this is called "whale eye" and occurs when the dog tries to turn his head away while still keeping a vigilant eye on you. If you can't see his eyes because he is looking away intentionally or has his head buried, he is stressed. And, if you see his eyes dart around the room warily (as if looking for an escape route or other signs of impending doom), he is stressed. Your choices in these situations are not unlike the ones above, when the pet is hiding.

But, what if you don't see any of the stress signs above and begin to approach a dog at close range? Watch for narrowing of the eyes or a hardening of the stare. This can happen in the fearful dog that's been covering its fear well or in the confident dog that is simply saying, "Beware." Either way, these are often the first signs of that will undoubtedly escalate if you continue to approach or try to handle the dog. In this case, assess other signs of stress you may have missed.

Freezing when touched

You look in your dog’s eyes for signs of stress and he seems fine. You reach out to touch him and he freezes. You pull your hand away and try again, just to make sure you didn't imagine it. Nope. He freezes again. What does this mean?

Many people miss freezing as a sign that the dog has just about had enough and may soon become overtly aggressive if you push him any farther. It is not prudent to ignore this response, as a growl or bite will often follow. Like any other sign of stress, you will likely need to delay the intended activity until you can help your dog feel better about it.

Heavy breathing

We all know what relaxed breathing looks like. We do it pretty regularly. What if your dog breathing pattern changes as you approach with the nail clippers? If he starts panting, or even just breathing more rapidly, he's stressed. What if he starts yawning? This, too, is a sign of stress that's often overlooked. These breathing changes are your cue to find a less stressful way to do what you have planned for him.

Lip-licking

Unless you just fed your dog something tasty, you should not see him licking his lips. The two most common causes of this behavior are nausea and stress. If you are walking toward your dog with something a bit scary, you can bet it's stress. This behavior is often paired with panting or yawning.

The “shut down” dog

It is unlikely you will find your own dog shut down. This term describes the lack of behavior sometimes found in the profoundly stressed dog. It happens when the fear system switches to overload and the pet chooses neither fight nor flight. You see it in some shelter dogs and others that may have been punished excessively. The complete lack of behavior can make it look like the dog is mentally absent or extremely . If you do happen to see your dog shut down in a stressful situation, take note and seek help.

It's best to keep in mind that the shut down dog, if pushed too far, may "snap out of it" and try to escape or become aggressive.