In the northeastern part of Brazil, encompassing several states, is a harsh, dry, poor area generally called the Northeast (Nordeste). There is a specific cowboy culture there, distinctive and unique, and completely different from the gaucho cowboy culture of southern Brazil, Uruguay and Argentina. In the northeast, the cowboys are called vaqueiros - a Portuguese derivation of the Spanish word vaquero (from the Spanish word "vaca," meaning "cow"). The land has large areas of scrubby, thorny vegetation, called Caatinga, which has affected some details of the vaquiero style.
They are known for their distinctive style of leather clothing, necessary for riding in the thorny scrub. Pants, chest-protectors, jackets with very long sleeves, and special hand guards are worn, and horses sometimes wear chest-covering breast-plates, too. The hats and jackets are often decorated with intricate cutwork and stitching, as you can see a bit in this photo by Alexandre Severo (see more photos like this on Alexandre's flickr stream):
The vaqueiros are known for being proud and tough, and their horse-handling methods are said to be in the same vein. In this picture and this one, you can see the cavesson that is used in addition to the curb rein. It is usually made of metal, and sometimes serrated to make a rough edge against the top of the horse's nose. I heard about a good horseman in the São Paulo area (about whom I will post more later), who is making some efforts to offer workshops in the remote Northeast to educate the vaqueiros about gentler methods of horse training and riding. He said they tend to roll their eyes at the idea of something so "gay" as gentle horsemanship, but some are starting to listen.
Because of the heavy underbrush the vaqueiros work in, they do not use lassoes to catch cows, but have developed a method of running them down and grabbing them by the tail. This is not done just for work, but also as a sport, as can be seen in these action photos taken by Hugo Macedo. A variant of this type of cow catching has evolved into an arena sport, held at local rodeos, in which two riders gallop alongside a cow, one of them keeping the cow in a straight line, the other grabbing its tail and flipping it over onto its back before reaching the finish line. Tough sports from a tough part of the world.
Here is another flickr set that includes this super photo of a vaqueiro dressed up in finer tack and apparel - for a festival or parade, perhaps. This horse has the leather chest protector I mentioned. The photo set has other great photos showing tack, apparel and horses.
The horse of the vaqueiro is the Nordestino. Often gaited, having incredible stamina and resistance to heat and thirst. There used to be a breed organization, but last I heard it has become defunct, so the breed is not registered or regulated in any way. Here is a sweet-faced gray one.