Young Gemsbok peer over the grass. Their horns grow immediately at birth, and young gemsbok look proportionally the same as adults. Many hunters have been fooled spotting a young one in the field, and thought it a mature animal. One giveaway is the whitish color of the horns, which gradually turns black by age 5-8 when mature. When they get past 10 years of age, the horns start to crack.