What primary factor served as the unforgiving crucible for the Fila Brasileiro's development?

Answer

The harsh, demanding environment of the New World.

The breed developed over centuries in Brazil where the harsh environment, including jungles and the presence of wild animals, demanded unparalleled guardianship capabilities.

What primary factor served as the unforgiving crucible for the Fila Brasileiro's development?
DogbreedFila Brasileiro