The Hamer are agro-pastoralists in the southern Omo Valley, numbering about 30,000. They are known for their body adornment, wearing a multitude of colorful beads. Women adorn their necks with heavy polished iron jewellery. Hamer society consists of a complex system of age grades. Passing from one grade to another involves complicated rituals. The most significant ceremony for young men is the "jumping of the bull" - the final test before passing into adulthood and marriage. Several days before the ceremony, initiates pass out invitations in the form of dried knotted grass. The ceremony lasts three days. Late in the afternoon on the final day, ten to thirty bulls are lined up side by side. The naked initiate runs and vaults onto the first bull's back and then runs along the whole line. Then he turns back to repeat the performance in the opposite direction. He must make this unstable journey without falling. Upon completion of the ceremony the new bride and his other female relatives submit to a ritual flogging by the initiated one, and continue to display with pride the resulting scars, regarded as a proof of their devotion to their husbands