The Cão de Gado Transmontano or Transmontano Mastiff is a breed of livestock guardian dog from Portugal. It originates in the historical province of Trás-os-Montes e Alto Douro in north-eastern Portugal, and is a rare breed confined mostly to this area.
Image credit: CARLOS, CC BY-SA 4.0
Adapted from Wikipedia, CC BY-SA 4.0 — https://en.wikipedia.org/wiki/C%C3%A3o_de_Gado_Transmontano