What is the origin of the idiom "chase one's tail" and when to use it?

The origin of the idiom "chase one's tail" is related to the behavior of dogs, who may chase their own tails in circles without ever catching them. The phrase has been in use in English since at least the early 20th century, and it is often applied to situations where someone is engaging in fruitless activity, such as repeatedly trying to solve a problem using the same ineffective approach. In general, the phrase is used to describe a situation where someone is expending a lot of energy without making any real progress towards their goals.