The buffalo horns reach their final size in 4 years for the female, and 5 years for the male. At the age of 2, the male shows a horny protuberance at the base of each horn. Meanwhile, the frontal bone supporting the horns thickens until the two bumps meet to form a real helmet that covers the entire forehead. As the buffalo grows, its horns lengthen, diverge and then curve below the base of the skull and upward. The head of the female does not have a horny shield and its horns are flatter, smaller and narrower.