What are caraballos?

Some articles on caraballos, caraballo:

Geography Of The Philippines - Terrain - Luzon - Cordilleras and Caraballos
... The Cordilleras and Caraballos, together with the Sierra Madre Range, form the main mountain system in Northern Luzon ... The first, called Caraballo del Sur, forms the nucleus of the system and has its highest peaks in the border between the provinces of Abra, Ilocos Norte and ... The next, called Caraballo Occidentalles, is further divided into 2 ranges, the Cordillera Norte and Cordillera Central ...