The Fila Brasileiro, or Brazilian Mastiff, is a massive molosser developed on Brazil's colonial-era ranches and plantations from European mastiff, bloodhound and bulldog-type dogs. It worked as an estate guardian, cattle dog and big-game catch dog, and its name comes from the Portuguese verb filar, to grab and hold. Loose, thick skin, heavy dewlaps, a croup set higher than the shoulders and a rolling, camel-like pacing gait make it unlike any other mastiff.
The breed standard describes a dog that is docile and devoted with its own family but naturally aloof toward strangers, especially on its home ground, a trait breed fans call ojeriza. That intense territorial guarding is why several countries ban or restrict the breed. A Fila needs an experienced owner, careful socialization, secure fencing and controlled introductions for life.