A male giraffe also needs a hard head to win the competitive game of courtship in the veldt. From the age of four, when his horns first attach to his skull, a bull giraffe grows layer after layer of new bone which accumulates around his skull, especially over his eyes and on his nose. Gradually, his head becomes a massive club that he uses to strike competitors. The ritual of fighting for a female begins with a stiff-legged dance. After rubbing necks and leaning on each other to gauge their relative strength, two bulls swing their heads up and over the shoulder, often missing but sometimes hitting each other's flanks and necks. Between blows, there are long pauses when the animals stand motionless.