The Ostrich is a large flightless bird native to Africa. It is the only living species of its family, Struthio. Ostrich are in the same order as kiwis, emus, rheas, and other ratites. They are the largest living species of any bird and lay the largest of eggs of any living bird (extinct elephant birds of Madagascar and the giant moa of New Zealand laid larger eggs). The diet of the Ostrich mainly consists of plant matter, though it also eats insects. It lives in groups which contain between 5 and 50 birds. When threatened, the Ostrich will either hide itself by lying flat against the ground, or will run away. If concerned, it can kick with its powerful legs. Female Ostrich usually weigh between 140-290 pounds, with males weighing up to 340 pounds. The feathers of adult males are mostly black, with white primaries and a white tail. Females and young males are a greyish-brown and white. The head and neck of both the male and female are nearly bare, with a thin layer of down. Their long neck and legs keep their head 6-9 feet above ground, and they are said to have the largest eyes of any land vertebrate. Their lifespan is up to 45 years. They have the ability to run up to speeds of 45 miles per hour, the top land speed of any bird. Ostrich are farmed around the world mainly for its feathers, which are decorative and can be used as feather dusters. Its skin is used for leather products and its meat marketed commercially.