These masks, called Mangam, were worn in ritual contexts associated with healing diseases, marking rites of passage, or securing agricultural success. The tall and upswept horns refer to waterbuck and reedbuck antelopes (“big” Mangam), and the circular horns stand in for the dwarf forest buffalo or bushcow (“small” Mangam). Artists could vary the form by utilizing the natural branching of tree limbs or by adding a small human face at the end of the snout. Despite their powerful animal aspect, subtle embellishments, such as lines of scarification, indicate their hybrid human aspects. Mangam were made by a cluster of peoples living in the escarpments south of the Jos Plateau, located north of the Benue River.
It is not surprising that these boldly proportioned crest masks captured the attention of artists and collectors early in the twentieth century. The large number of masks that exists in collections, along with more than one hundred photographed in the field in the 1950s and 1960s, exhibit a stunning degree of variation.
Source: Gallery Wall Text, Central Nigeria Unmasked: Arts of the Benue River Valley, 2011