What is a key reason for a Jack Russell to be sturdy?

A key reason for a Jack Russell to be sturdy is to assist in hunting and burrowing activities. This breed was originally developed for hunting foxes and small game, requiring physical traits that enhance their capability to navigate through challenging terrains and environments. A sturdy build enables them to endure the physical demands of hunting, such as chasing prey over long distances and maneuvering through dense underbrush or burrows. Their resilience and strength are essential for effectively working in the field, as they need to be agile and capable of handling the rigors of their hunting roles. This sturdiness supports their active lifestyle and agility as they perform their tasks, making it a critical characteristic for the breed's intended purpose.