Portuguese Cattle Dogs have a very distinctive bark: highly resonant, generally starting with low tones and ending in a long high pitch, rather like screeching.
About the Portuguese Cattle Dog
Portuguese Cattle Dogs are mastiff-type lupoid dogs characterized by an almost rectangular body. They are vigorous animals of pleasant overall appearance, sometimes with a rather striking color. Their gait is free, easy and energetic.
Loyal and docile with people they know, Portuguese Cattle Dogs do a great job protecting livestock from attacks by the many wolves that still prowl the mountains of northern Portugal. They are simply awesome watchdogs, seeming never to switch off even for a moment. These dogs carry themselves nobly but they are hardy mountaineers and that severe expression they wear is fearsome.
Source: key facts and characteristics sourced from Fédération Cynologique Internationale (FCI)