Note the kudu antelope horn being played in the foreground. Animals horns, especially that of the kudu, are used as musical instruments by many East African tribes. A hole is made near the point of the horn, and sometimes finger holes are added along the side to give different notes.
Credit: photo copyright © Elsa Dionísio; reproduced by kind permission. Originally published as part of her superb page (in Portuguese) on Makonde dances (http://www.terravista.pt/Bilene/1494/danca.html).