Filas are descendants of the 15th-century English Mastiff, Bloodhound, Bulldog and Rafeiros. From the Bloodhound, he inherited loose skin and keen sense of smell. The Mastiff contributed compact body, courage and an ever-alert disposition. The Bulldog added the unforgiving impetuous temperament. In early history Filas held escaped slaves unharmed for the master.
The Fila has vigor and authority to its elastic pacing gait. A very large, square, heavy and massive head holds deep, sad eyes. His honesty in his antipathy to strangers invading his territory or threatening his master seems more awe-inspiring than the word 'Ojeriza,' used to describe the Fila's aversion to strangers.
This muscular, powerful breed is 23½ to 29½ inches tall, weighing a minimum of 90 pounds. Bitches according to the breed standard, must be between a minimum of 23½ inches tall and a maximum of 27½ inches tall, and weigh a minimum of 90 pounds at adulthood (approximately 3 years). Dogs according to the breed standard, must be a minimum of 25½ tall to a maximum of 29½ inches tall at the shoulder, and weigh a minimum of 100 pounds at adulthood . Below minimum height or weight for both sexes is a disqualification, to be somewhat larger than maximum is a minor fault.
Colors include all shades of fawn brindle and black (some dispute the color black). Up to one-quarter of the dog may be white, but white is only allowable on the tip of tail, feet and chest. The overall appearance is catlike. They walk with a rolling, lion-like gait. They can leap and run and stalk in a feline imitation of movement.
Despite the no-nonsense attitude of the Fila, its devotion to its family is legendary. It does not permit familiarity of strangers. Clearly extensive socialization and obedience training are essential to give this breed a frame of reference for normal human interaction, so it will not mistake a pat on the back of its master, by a friendly stranger, as an attack.
Filas are used as cattle drovers, jaguar, boar and bear hunters, as well as home and ranch guard dogs. They are not typically animal-aggressive. A Fila's primary bond is to its master and family, and for this reason they are not suitable as flock guardians, as they desire to be near their human flock. In fact, enormous dedication to their family has been observed as they present a docile, meek, sober, obedient and playful attitude, often extending a paw to touch you, requesting hugs and petting. A friend to you always.
Filas are easily 'read' when they are reacting to a perceived threat. The cold-eyed stare, lowering of head, readiness, long body posture, low growl, all tell the world: 'Beware, I am watching your every move!".
Filas should never be judged solely on appearance. Not only should a quality Fila be beautiful but it is essential they be of good character and temperament and have structural soundness.
Due to the intensity of this breed's temperament, clearly they are not suitable for just everyone. Educated and responsible owners are a must.