Most people think that when a dog wags his/her tail he/she is happy; however, this is not always the case. Many wagging tails are indicative of happiness, but this behavior can also be a signal of fear, insecurity, anxiety, or a warning of a threat.
Stanley Coren, PhD has studied the meaning of different wagging tail movements for years. He explains that the tail's position “can be considered a sort of emotional meter”. According to Dr. Coren, a middle height suggests the dog is relaxed and if the tail is held horizontally, the dog is attentive and alert. He also explains that as the tail position moves further up, it is a sign the dog is becoming more threatening, with a vertical tail being a clearly dominant signal meaning.
On the other hand, Dr. Coren says, as the tail position drops lower, it is a sign the dog is becoming more submissive, is worried or feels poorly. The extreme expression is the tail tucked under the body, which is a sign of fear. Dog tail’s movement give additional meaning to the signals. The speed of the wag indicates how excited the dog is. Meanwhile, the breadth of each tail sweep reveals whether the dog's emotional state is positive or negative, independent from the level of excitement.
Here are some common dog tail movement combinations:
Slight wag (each swing of only small breadth): is usually seen during greetings as a greeting.
Broad wag: this is a friendly signal. It means that the dog is not challenging or threatening you. A broad wag also means that the dog is pleased and happy.
Slow wag with tail at 'half-mast'”: according to Dr. Coren, this is the less social of all the other tail signals. Slow wags with the tail in neither a particularly dominant (high) nor a submissive (low) position are signs of insecurity.
Tiny, high-speed movements: mean that the dog is about to do something, usually run or fight. A tail that is held up high and moves fast means that the dog is threatening you.
About the author
Dr. Stephanie Flansburg-Cruz practices mixed animal veterinary medicine and she has a special interest in shelter medicine and animal welfare. Stephanie enjoys volunteering at local animal shelters, reading, writing and traveling.
Coren, S. (2011). What a Dog’s Tail Wags Really Mean: Some New Scientific Data. Specific tail wags provide information about dogs’ emotional state. Psychology Today. Retrieved on April 15 from: https://www.psychologytoday.com/blog/canine-corner/201112/what-dog-s-tail-wags-really-mean-some-new-scientific-data