When and Why Dogs Back Hair Standing Up?

For new dog parents, seeing their dogs' back hair suddenly stand up is surprising. But if you have had a dog for years, this is not new to you. There is no fixed reason why dogs' back hair stands up. They may do it out of excitement or fear, while playing or sleeping, or for other reasons.

This back-hair standing behavior is a way dogs express their feelings. Most often, this is totally normal, and you do not need to worry at all. But if your dog is doing it out of fear or pain, then it should be concerning.

This is why you need to know when and why dogs' back hair stands up. Other expressions and body posture are also related. By knowing the reasons, you can easily find a solution for your beloved furry dog.

What Are Hackles on a Dog? 

When a dog's hair stands up, it is known as piloerection, a nonverbal expression that is an involuntary response to a mental stimulus. The technical term for this is “hackles.” The hairs that stand up are supported by a unique set of muscles called pili muscles along the dog’s spine. So, the hackles condition happens when the dog’s fur follicles send a message to the parasympathetic system, the muscles contract, and the hackles stand up.

In simple words, hackles are the hairs along a dog’s back that can stand up or lie flat. They run from the neck down to the tail. This happens because of tiny muscles called erector pili muscles. When these muscles tighten, the hair stands up.

When a dog’s hackles rise, they make it look bigger and more intimidating. This can help them in social situations with other animals or people. Now, let's understand what dogs' hairs standing up means.

What Does It Mean When Dog Hair Stands Up?

Raised hackles are a sign of how your dog is feeling. You’ll often see them when a dog feels scared, excited, or alert. This is basically their change in emotional state.

For instance, if a dog feels threatened, the raised hair can make it appear larger and bigger. Then, the dog can be in a defensive posture and fight against it. Again, a thin line of erected hair from the shoulders to the tail can show a more confident dog. But a broad patch over the neck and shoulders highlights low confidence.

Conversely, when a dog is excited or curious, the hair might stand up as part of an overall heightened alertness.

So, you can see your dog hackles can mean different things in different situation. You need to observe your dog body language, environment, and other scenarios around them. Like if they are playing or simple relaxing. If you want to be a emotional partner of your furry friend and understand your dog’s feelings better, then you better understand when dogs have hackles.

When and Why Dog Hair Stands Up?

Now, let us understand when and why dog hair stands up. The simple answer is when the dog's condition is arousal, fear, excitement, surprise, ambivalence, or pain. These can be the possible reasons why dogs with hair stand up on their back.

Standing hair on dogs back is not a dog weird behavior, instead common. There is nothing to worry about unless they are doing it out of fear or pain. If so, you need to immediately take an action to help your beloved pet dog.

Here are some more common reasons why dogs hair stand up on back, you can go through them to figure out similar situation of your dog.

When Threatened

One of the common defensive reaction is hair standing up on the back. This happens when your dog is threatened. This piloerection makes the dog seem larger and more intimidating. They can make themselves bigger to fight against potential threats.

This is a natural instinct of animals to deter predators or rivals. So, if you ever notice your dog's hackles raised in a situation when they were frightened, then the reason is now clear to you.

Hackles: Raised along the back.

Body Posture: Stiff and tense, possibly leaning forward.

Ears: Pulled back or standing up, depending on the breed.

Tail: Held high and rigid or tucked between the legs.

Facial Expression: Lips might be pulled back to show teeth, eyes wide and focused.

When Aroused

Another reason a dog’s hair may also stand up when they are aroused. This can be due to excitement, curiosity, or anticipation. This physiological response is linked to heightened states of alertness. You can observe during their play or when the dog meets new people.

The raised hairs often show the dog’s intense focus and readiness to engage. During this time, they stay in an alert position with an eyes wide expression.

Hackles: Raised, especially near the shoulders.

Body Posture: Alert and forward-leaning, muscles tensed.

Ears: Pointed forward or moving, listening closely.

Tail: Held high and wagging slowly or stiff and slightly raised.

Facial Expression: Eyes wide and focused, mouth closed or slightly open.

When Changes Temperature

Changes in temperature can also cause a dog’s hair to stand up.

In cold weather, piloerection helps to trap air close to the skin. This provides extra insulation and warmth. Conversely, in hot weather, raised hair might help in cooling. The halces increase air circulation around the skin.

You may have heard stories of dogs surviving in the cold. They use this hackle as one of their survival mechanism.

You can say this is a natural thermoregulation process for dogs. They use it to maintain a comfortable body temperature according to the environmental changes.

Hackles: Raised slightly due to cold or as a reaction to a sudden temperature change.

Body Posture: Normal or slightly hunched if the dog is cold.

Ears: Relaxed, though they may flatten slightly in response to the cold.

Tail: Relaxed or tucked slightly to conserve warmth.

Facial Expression: Calm, though the dog may seem more alert if the temperature change is sudden.

When Playing

When your dog plays, it stays excited and energetic. This can make their back hair stand up.

The dog simply get very excited and want to make the playtime more engaging. They interact with other dogs or play with you hence their excitement show up hackles.

You can observe their tail wagging energetically with a happy expression.

Hackles: Raised, often near the shoulders, but in a playful manner.

Body Posture: Play bow (front legs lowered, rear end up), bouncy movements.

Ears: Perked up, moving with excitement.

Tail: High and wagging energetically.

Facial Expression: Open mouth, possibly panting, relaxed eyes, and a happy expression.

While Sleeping

Even while sleeping, a dog’s hair may sometime stand up due to various reasons. One reason is they are sleeping a lot and dreaming a excited or fearful dream. As a reaction their back hair can stand up. Or sometimes sudden movement can cause the hair stand up.

If your dog have hackles in their sleep do not worry about that. This is not unusual behavior.

Hackles: Slightly raised due to dreaming or sudden muscle contractions.

Body Posture: Relaxed and lying down, possibly twitching during dreams.

Ears: Relaxed, might twitch in response to sounds or dreams.

Tail: Relaxed, possibly twitching in response to dreams.

Facial Expression: Relaxed, might show slight movements like twitching or soft growling if dreaming.

Relaxed Dogs

You dog is simply relaxed laying on the ground or unhappy with a calm facial expression can show hackles too. This reason may have been unknown to you. But dogs hair do stand up when they are fully relaxed.

You can figure out this by their calm facial expression and how they avoid eye contact. They may also wag their tails gently and slowly.

Hackles: Flat, lying smoothly against the back.

Body Posture: Loose and comfortable, possibly lying down or standing with a relaxed stance.

Ears: Neutral, not pinned back or perked up, often slightly forward or to the side.

Tail: Held in a natural position, wagging gently or hanging loosely.

Facial Expression: Soft eyes, with a calm gaze; mouth might be slightly open, tongue relaxed, and possibly panting lightly.

Movement: Smooth and easy, with no signs of tension or hesitation.

Fearful or Anxious Dogs

This reason is almost same when your dog is threatened which makes them anxious. Though a dog can become fearful for many other reasons. So, try to find out other facts like if the dog looks tensed. They may not wag their tails a bit out of fear. Sometimes, the dog shake or tremble. In such casem try to calm down the dog and stay with him.

Hackles: May be raised, especially along the shoulders or down the back.

Body Posture: Tense and crouched.

Ears: Pinned back against the head or flicking nervously

Tail: Often with little or no wagging.

Facial Expression: Wide eyes with dilated pupils, avoiding direct eye contact, shallow breathing.

Movement: Hesitant, slow, or erratic, often with signs of shaking, trembling, or pacing.

Dog Breeds With Raised Hackles

Certain dog breeds are more likely to show raised hackles due to their physical build and behavior. Breeds like the German Shepherd, Doberman Pinscher, and Rottweiler often have strong, noticeable hackle reactions. These breeds have muscular bodies and tend to be more sensitive to their surroundings. Their hackles are strong and seem big.

Similarly, breeds such as the Rhodesian Ridgeback and Alaskan Malamute also have visible hackles. While many breeds can raise their hackles, the extent and visibility of this reaction can differ.

On the other hand, some dogs, like Moyen Poodles and Poodle mixes (Labradoodle, Bernedoodle, Goldendoodle), have less noticeable hackles because of their curly coats.

Now, what is your dog breed? If it is a German Shepherd, you know why the frequent hackles come. This is because of their natural breed instinct. With a medium poodle, you may notice very few standing hairs in your pethood.

Conclusion

As a good pet parent, you must have gone through all the reasons why your dog's back hair stands up.

When a dog is threatened, fearful, in pain, or simply playing or sleeping, it has hackles. This is not something a pet parent should be tense about. But by knowing the reasons and other factors like their tail wagging or body gestures, you can be your dog's emotional partner.

FAQS

Do All Dogs Have Hackles?

Yes, all dogs have hackles, which are the hairs along their back that can stand up. But some breeds may be less or more prone to hackles.

Are Raised Hackles Signs of Aggression?

Raised hackles don't always mean aggression. They can also show fear, excitement, or other emotions.

What Do You Do When Dog's Hackles Raised?

Stay calm, understand the situation, and avoid making sudden movements while giving the dog space.