Blesbok are territorial, with a social structure consisting of bachelor herds, and breeding herds consisting of a dominant male with his females. This tireless, nimble-footed athlete of the grasslands is particularly possesive towards his harem, and performs an impressive ritual of threatening behaviour to warn off rival males. The blesbok resolutely eyes its opponent by standing very still, with its head held high; it then issues a volley of snorts, lowers its head, and leaps into the air clashing horns with its rival. The blesbok male marks its territory by making dung heaps and also by rubbing scented glands on its face against blades of grass. Expectant mothers stay with the herd to give birth to single calves in early summer. Calves are able to stand, and to run with their mothers, within 30 minutes of birth: they tend to form either nursery groups within the herd, or join bachelor herds, from about 10 months old. Male calves remain in their mother's herd until calving time; while females sometimes remain with their mothers for up to two years.