The Cão da Serra de Aires (FCI no. 93) is a medium sized breed of dog of the herding dog type and is one of the indigenous regional dogs of Portugal. Called the Portuguese Sheepdog in English the original name refers to the Serra de Aires a range of hills or mountains marking the boundary between Ribatejo and Oeste north of the Tagus river. The breed is nicknamed the cão macaco (monkey dog referring to the macaque or monkey) for its furry face and lively attitude.