The Cao Dos Mourey can be traced back to a breeding program that began more than 35 years ago and stems from the English banddog. The first research into breeding this dog began in 1975. The primary breeds that were used in the breeding program were the terrier, bulldog and mastiff. The goal of the breeding program that ultimately produced the Cao Dos Mourey was to recreate a working class mastiff dog that had been popular prior to the 20th century. The dog we know today takes many of its characteristics from the different dogs that were used in the breeding program. For example, it is said to take its tenacity from its bulldog ancestors.
This breed of dog can reach up to 180 pounds and is not a dog that is suitable for someone who is not able to handle the massive size of this breed. The size of this dog makes it extremely powerful. As such, it is a great working class dog. While it would not be typically expected, this breed of dog is capable of speeds that are not typically seen in such a large dog.