Tail does not wag the dog when it comes to agility, scientists find

Scientists have found that the tail cannot wag the dog.

An international team decided to investigate the purpose of the dog's tail after studies showed that numerous animals from lizards to squirrels use their tails to pull off impressive maneuvers.

Cats don't need a tail to flip themselves over and land on their feet, but they do use their tails for balance and as a counterbalance to perform extreme hunting moves.

With dogs more inclined to stay on the ground, scientists weren't sure if the animals' tails helped with agility or if they were used to fend off flies.

In order to learn more, Dr Ardian Jusufi and his colleagues built a mathematical model that allowed them to check what happens when dogs twist and turn their torsos.

Their conclusions are in a preprint titled: "Tail wags the dog is not supported by biomechanical modelling." In the paper, which has not been peer-reviewed, the researchers describe how the modelling showed tail movements made no difference to a dog's trajectory when it jumped into the air.

The finding shows that tails aren't as important for agility in dogs as they are for other animals. The researchers found that moving the tail mid-jump altered the dog's trajectory.

The authors say that tail movement has little to no effect on jumping. The largest amount of center mass movement across all species is achieved by using the tail during jumping.

Dogs use their tails for other things, such as communication and pest control, but not for agility in maneuvers.

Dogs use their tails to communicate everything from dominance to fear. A high tail indicates a dog is willing to play, while a stiff tail indicates a threat. When the tail is tucked between the legs, the animal might be afraid, but loose wagging from side to side shows it's friendly.