“Africa” premieres Jan. 8 on Discovery Channel - Article Photos 1/2

Rival male giraffes fight in the Hoanib, a river of sand in Namibia. Combat is usually avoided by giraffes but, just occasionally, when the stakes are high enough, males will violently swing their heads to deliver "sledgehammer" blows. The Africa team followed one male for over a month to capture behaviour unlike anything seen before. Photo Credit: Discovery Channel/BBC