What Makes the Fur Look Wrinkled Down a Dog's Spine?

Various types of dog fur exist, from super short to so long the fur touches the ground. One thing all dogs have in common, however, is a patch of fur along their backs that has a different texture and appearance than the rest of the coat. That section of fur might seem insignificant, but it serves a greater purpose.

All dogs have hackles along the base of their spines, which usually presents as fur that is coarser and denser than the rest of their coats. Depending on the breed of dog, hackles generally have a wrinkled or zigzag appearance and run from a dog’s neck or shoulder blades down to the base of his tail. Dogs can use their hackles to communicate their feelings or to appear taller in a threatening situation.

You may occasionally see your dog raise his hackles. The section of your dog’s coat that normally has a wrinkled appearance will stand on end, or puff up. This is called piloerection, which is an involuntary physical response your dog will have to particularly frightening, exciting or stressful situations. Similar to how humans get goose bumps when they’re quite frightened or nervous, piloerection is a physical response to a surge of adrenaline caused by a variety of situations or stimulants. Piloerection is often misunderstood as a sign of aggression, but that isn’t necessarily the case. Piloerection can be a signal that your dog is afraid, stressed or agitated; it can also mean your dog is excited. It’s common for small or nervous dogs to raise their hackles when a larger dog is approaching as a way of appearing bigger or taller than they actually are.

Although all dogs have hackles, they can be more subtle in some breeds than in others. Dog breeds with short, bristly coats generally have more distinct hackles than dogs with long, curly or fluffy coats. For instance, the hackles on a Basenji will be much more pronounced than on a poodle or Shih Tzu. Despite how obvious or visible a dog’s hackles are, he will experience the same physical response of piloerection as other dog breeds.

As a dog owner, witnessing your dog’s piloerection is an opportunity for you to learn and understand your dog’s behavior, temperament and body language. Because piloerection is frequently misunderstood as a sign of aggression, it is especially important for you to know what stimulants cause your pooch to raise his hackles. In addition to his raised hackles, your dog will use other body language to communicate how he is feeling. Evaluating the way your dog is carrying his tail, his ear position and his overall posture helps you interpret your dog’s response. The messages dogs communicate through their body language can be subtle, but understanding your dog’s mannerisms and behavior is key to keeping you and your pal safe in any situation.