While few biologists have studied giraffes extensively in the wild, we do have a sketchy knowledge of their behavior. However, what we know raises as many questions as answers. Divided into nine subspecies based on coat pattern and horn number, giraffes form herds like many hooved mammals. But unlike most herding hoofed species, which form tight-knit and stable groups, giraffe herds are unusually informal. The fifteen-odd females and young in a herd may be scattered over a considerable distance and may leave and rejoin at will.
Males mature sexually at about four years but keep growing until they reach about eight years.
While young males often roam together in loose association, older males tend to be solitary. The older, larger bulls are dominant and devote much of their time to patrolling for females in heat. A dominant bull will approach a herd, draw himself up to his full height and stare at a potential rival. While this is usually enough to make the adversary leave, once in a while a subordinate bull stands his ground and a fight ensues. Giraffes fight by charging and swinging their heads at each other as hard as they can.