Определение и Значение "eager beaver"

What is the origin of the idiom "eager beaver" and when to use it?

The origin of the phrase "eager beaver" is believed to date back to the mid-20th century, specifically during World War II. It is thought to stem from the beaver's industrious nature and persistent work ethic. This idiom can be used to describe employees who are proactive and go above and beyond their regular duties, students who are highly motivated and actively participate in their studies, or anyone who consistently demonstrates a strong drive and eagerness to accomplish tasks or achieve goals.