A Dog’s Tail Serves More For Communication Than Physical Function

Dogs and tails go together like snips and snails, but new research from an international group of scientists suggests that a dog’s tail doesn’t serve as a functional or protective feature like a lizard’s or squirrel’s but more of a way to communicate–with other animals and with us. 

Where other studies suggest that the tails of squirrels, lizards and other animals may help with balance or even hunting, this study suggests that a dog’s tail is likely more a communication tool. 

The scientists involved in this non-peer-reviewed paper titled “Tail wags the dog is unsupported by biomechanical modeling of Canidae tails use during terrestrial motion, wanted to look into what the tail did with regard to movement facilitation, or whether it helped protect from nuisances like bugs or flies, and whether or not they were instead communication tools.

Dr. Ardian Jusufi studies animal locomotion at the Max Planck Institute for Intelligent Systems in Stuttgart, Germany. With his international teammates from the Friedrich-Schiller-University and the Georgia Institute of Technology, he developed a mathematical model that let them look at what happens when dogs move their legs and tails, use their torsos and when they jump.

The research team concluded that the tail movements of dogs didn’t seem to have any effect on the trajectory of a dog as he jumped, with the implication that a tail isn’t as vital for agility in dogs as it is in other animals. 

According to the paper, inertial impacts of the tail moving on complex activities like jumping have little to no effect and using the tail during jumping only offers very low amounts of the center of gravity stability. They believed then that dogs’ tails were necessary for other means, like communication and possibly pest control, but not for balance or anything that requires agility.

Other research has suggested that dogs use tails to convey messages like humans do with their body language. From showing friendliness to submission to fear and dominance, dogs use their tails to express mood, willingness to engage in play or even the detection of a threat. 

The paper concludes that dog tails may have once served a larger evolutionary purpose, but now they are what is used to relay feelings, which is a very important and useful skill for pack animals.