Dog Behavior Series: Hackles Up
A dog’s raised hackles are an involuntary reaction to intense feeling
As we’ve been learning over the past few weeks with our Dog Behavior Series, dogs use every part of their body to communicate. From the tip of their tongue to the tip of their tail, dogs use body language to express a wide variety of emotions. They even use their hair to communicate! All dogs have a line of hair running down their back that raises or lowers in response to certain outside stimuli. Many call these hairs a dog’s hackles. When a dog raises their hackles, their owner might immediately think that the dog is being aggressive. However, raised hackles doesn’t always mean aggression. It can indicate a variety of feelings, including aggression, depending on the circumstance. By learning more about this biological phenomenon, owners can better discern what their dog is trying to tell them.
The biology of “hackles”
The scientific term for raised hackles is “piloerection”. Certain hairs located along the spine of a dog from their neck to the base of their tail are connected to small muscles called arrector pili”. These muscles contract under certain circumstances causing the hair shaft to move, making your dog’s hair stand up and puff out. This contraction of tiny muscles is an involuntary biological phenomenon to outside stimuli. Raised hackles is very similar to humans getting goosebumps during a good song or emotional moment. The phenomenon responds to the sympathetic nervous system. The sympathetic nervous system creates the fight or flight response. These responses are involuntary and activated by adrenaline and higher stress situations. Dogs have no control over whether their hackles raise or not.
What is the purpose of “hackles”
In terms of evolution, “hackling” is way to increase chances of survival. By raising their hairs, a dog can look much bigger than it actually is. In the wild, if a dog ran across an unfamiliar dog or animal, the adrenaline from the encounter would raise the hair and make them look more intimidating. The hope would be that the other animal would back off and not start a fight.
In the world of domestic dogs, raised hackles can be the result of feelings such as fear, arousal, surprise, insecurity, excitement, nervousness, or defensive behaviors. The meaning behind their raising is all dependent on the context of the situation. Younger dogs who are still unsure of their surroundings and unsure of how to react may raise their hackles. In general, piloerection is just an involuntary reaction to an intense feeling. Stiffness in the body or tail can help you deduce what the specific feeling is. Is your dog very stiff and alert with hackles raised? In this case your dog may be feeling nervous or threatened. If your dog is more relaxed and playful with hackles raised, it could be that they are just feeling very excited!
Because of the involuntary nature of piloerection, it’s important as owners to assess the situation when it happens. Overstimulation and high adrenaline can lead to more aggressive behaviors and should be avoided. If your dog’s hackles are raised, consider modifying their environment to lower the amount of stress.