Pastou

This house dog barks ferociously every time I pass but he is trained to bark not bite.  I have walked in the mountains and had to take a detour as the pastou does his job standing between me and his flock.  The term "pastou" (pronounced patou) is derived from the word "pastre", meaning shepherd in old French and designates a shepherd's dog as it was understood in times past. Unlike a herd dog, the role of the guard dog is not to drive the sheep but rather to protect them from wild animals or feral dogs. Usually walking at the head of the flock, the patou inspects the terrain before the arrival of the sheep, then establishes a zone of protection around the flock that allows him to anticipate the approach of any intruder.

Born in the sheepfold, the dog is brought into contact with the sheep very early. At two months he is separated from his mother and siblings to sleep, eat and live with the sheep he will be guarding. His thick white coat and floppy ears allow him to blend in with his charges and in time he is totally accepted by them. During his first two years of life the shepherd is careful not to stroke or caress him or in any way treat him as a pet in order that he bond as closely as possible with the sheep.

These mountain dogs are not attack dogs but protect by dissuasion. Their presence and large size alone discourages predators. The first reaction of the guard dog is to bark, to warn the stranger of his presence and alert the shepherd and the flock. At the same time, he places himself between the sheep and the intruder..
If the intruder ignores his warning or if the predator is agressive, the dog may then make physical contact.