Common ostriches usually weigh from 63 to 145 kg (139-320 lb). At sexual maturity (two to four years), male common ostriches can be from 2.1 to 2.8 m (6 ft 11 in to 9 ft 2 in) in height, while female common ostriches range from 1.7 to 2.0 m (5 ft 7 in to 6 ft 7 in) tall. Their lifespan is up to 40-45 years. When threatened, the ostrich will either hide itself by lying flat against the ground, or run away. If cornered, it can attack with a kick of its powerful legs.