Reading your dog's behavioral cues, or body language, can sometimes be fairly intuitive. Most owners know what a play bow looks like or recognize that a dog with its tail tucked between its legs is frightened or uncomfortable.
Some of your dog's body language may be harder to interpret, though. The position of your dog's ears can change based on their emotions. Your dog can put their ears back for a variety of reasons.
It's important to remember to look at your dog's body language as a whole. Looking at what their eyes are doing, if their facial muscles are tense or relaxed, and where their center of gravity rests (if they are leaning away from you, if they are crouched or hunched, etc.) can tell a lot about their attitude. This is especially true for dogs with long, pendulous ears, like Bloodhounds, as they obviously can't move them flat against their head.
By looking at other signals your dog is giving alongside their ear position, it can become easier to determine what your dog is trying to tell you. That being said, here are some reasons your dog may put their ears back.
Some dogs' ears are not naturally pointed, so when they are relaxed it stands to reason that they would be laid back in their natural position. If your dog's ears are back but not pinned flat against their skull, it may be because they are content.
Other body language you may see if your dog is relaxed is a 'soft' face (so no furrowed brow or lip curling), a loose and relaxed stance, and their tail will be down but relaxed and not curled between their legs.
Possibly one of the more well understood meanings behind a dog putting their ears back is a signal that they are fearful or at least wary about something. This can be especially true if you see this cue in conjunction with other 'fearful' body language.
A fearful or anxious dog may also be yawning and lip licking, avoiding eye contact (averting their eyes or completely turning their face away from you), opening their eyes so wide that you can see a sliver of the whites of the eyes (termed 'whale eye'), holding their tail down and close to the body, crouching down low, and/or posturing their body away from whatever is making them nervous.
A dog that is holding ears back, especially if they are pinned down flat, can be a sign that a dog is about to bite. This will often coincide with fearful or aggressive body language.
Other signs that a dog is being pushed towards biting may also include growling, snarling and lip curling, giving hard stares, bristling fur, and even lunging. Most dogs that bite do so out of defensive aggression versus offensive. They feel the need to protect themselves.
While this can be disheartening, worrying, and stressful to see, it is important to never punish your dog for growling or snarling. By scolding a dog for giving a warning about their feeling of fear or discomfort, they learn that those warning behaviors get them into trouble. Next time they may not give any warning before biting, and it isn't solving the reason why they are showing these behaviors in the first place.
Instead of punishing the growl, you should be looking to work out what is causing your dog to feel like this. For example, if they are being crowded by new people, then they should be given more space. You can then work on helping them feel more comfortable around strangers with positive reinforcement training.
Dogs may hold their ears back if they are in pain, likely due to fear of being hurt further if they are approached. In some rare cases, a dog with a particularly nasty case of an ear infection may be holding their ears back because they are painful. By holding them back they may be guarding them from further injury.
Your dog's ears are incredibly vascular and if they scratch or shake an itchy ear too hard, they may burst a blood vessel inside the ear pinna (the flap of the ear). When this happens the pinna will fill with blood, giving it a puffy, pillowy appearance. In fact, aural hematomas are sometimes called pillow ears because of this. Unfortunately, this requires veterinary medical attention to first drain the ear pinna of the pooled blood and then to treat the ear infection that gave rise to it.
Treating the ear infection and working out if there is an underlying cause is important to prevent major problems or reoccurrence.
Sometimes a dog may draw its ears back simply to better hear something that is happening behind them. You might notice this if you are in the garden with your dog and another family member calls them from inside the house.
Certain canine behavioral cues can be fairly straightforward to understand. Others, like ear placement, can be more nuanced. Sure, a fearful dog will put their ears back, but not all dogs that put their ears back are in fact fearful. If you want more information on how to decode your dog's body language, talk to a qualified canine behaviorist.