The term 'Big-Horned Goat' is a reference to the species of mountain goat known as the IBEX, which has four letters. The IBEX is a species of wild goat that is native to the mountainous regions of Europe, North Africa, and Asia. It is characterized by its large, curved horns, which can reach up to 1 meter in length. The IBEX is an agile climber and is well adapted to living in rocky terrain. It is also known for its thick, shaggy coat, which helps it survive in cold climates.