Perro de Presa Boliviano
The very rare Bolivian Bulldog is believed to be a result of crossing the primitive rain forest dogs with imported Spanish mastiffs and bulldogges, as well as other South-American working breeds. It is more likely that the indigenous pariah population benefited from the blood of the wardogs brought by the Spaniards and that it wasn't really a planned breeding effort, with the influence of imported breeds eventually lessening, especially in terms of phenotype.
It is said that a number of these crosses were brought to Brazil and Cuba in the 1800's and introduced into some local working bloodlines, but it isn't certain whether any actual breeding programmes ever existed, although there is mention of these dogs in some Cuban writings. The Presa Boliviano doesn't bark, which made it very appealing to hunters, as well as fighting enthusiasts, who nicknamed the breed "The Mute Bulldog". Some authorities doubt the existence of any pure specimens at present times, but there are also reports suggesting otherwise. This is a fairly small dog, with a deep chest, straight back and a muscled body. The head is similar to some bully breeds, apart from having a much narrower muzzle. The tail can be cropped, but is more commonly seen in its natural state.
The glossy coat is flat and short, usually black, red, brown or brindle in colour. Average height is around 18 inches, although smaller examples exist.