There is only one species of Ostrich, Struthio camelus. It is a remarkable bird holding several world records. It is the largest bird in the world being both the heaviest and tallest.
Males are larger than females, weighing in at more than 135 kg (300 lbs), as much as 345 lbs in some cases and standing over 2.6 m (8 ft). Some specimens have been as tall as 2.75 m (9 ft). Ostriches also lay the largest eggs in the world - up to 17.8 cm (7 in) x 14 cm (5.5 in), weighing about 1.65 kg (3.63 lbs) on average. The third world record held by Ostriches is the land speed record for a bird. Ostriches use running to escape danger so it is good for them to be able to run quickly. They have been timed running at 72 kph (45 mph) non-stop for 15-20 minutes during which time they travelled over 15 miles and left any predators well behind.
Ostriches are distinguished from other ratites by having only 2 toes, instead of 3, remaining on their feet. This is an adaptation to running similar to the reduction in toes seen in horses and gazelles. Males in full black/white and pink are quite colourful. They have bare thighs as a cooling device, though their head and necks look bare also they actually have a thin covering of down-like hairs. Ostriches have long black eyelashes which cartoonists exaggerate in order to make them look cuter.
Ostriches originally had a far larger wild distribution than they currently have, extending from SW Asia through Arabia to all of Africa. The Arabian subspecies, S. c. syriacus, has been extinct since about 1940). Wild Ostriches occur truly only in some wildlife parks in Central and Southern Africa. Though many Ostriches now live in farms all around the world, even in the UK and some farmed individuals released in South Australia continue to exist there as a feral population. A combination of better hunting techniques, i.e. cars and guns, and a fashion driven market for the tail feathers of the male are the principal causes for the reduction in natural habitat. Farming now produces Ostriches not only for their feathers, but also for the eggs, meat and the hides as a high quality leather.
Ostriches are omnivorous feeding mainly on seeds and other plant material but taking insects and other animals when they are available. They are nomadic, wandering wherever food is available. They need to take in water regularly despite rumours that they can live without drinking.
Ostriches are polygamous, with males forming a harem of several females. He constructs a nest which is little more than a shallow pit in the sand. Into this all the females he has mated lay their eggs, resulting in a collection of between 15 and 60 eggs as each female lays 6-14 eggs. These eggs are incubated by the dominant female during the day and the male at night. The dominant female may have help from other females. The eggs hatch in about 40 days and the brown and cream striped young are 'precocial' meaning that they are ready to leave the nest and feed within hours of hatching. Both sexes help to look after the young. Mating may occur at any time and a male may mate more than once with any given female. Egg laying normally occurs during the afternoon.
Ostriches have a courtship which involves the male sitting on his hacks, waving his wings around and throwing his head from side to side. During this time he makes a deep thumping sound or inflates his neck and emits a loud booming noise. A receptive female walks with her head down making a clucking noise and shaking her wings. The male will then approach her and she will sit down to allow him to mate with her. As with most birds mating does not take long.
Young Ostriches take several years to reach sexual maturity and females are usually ready to start mating in their third year, though males may be 4 or 5 years old before they are sexually active.
During the breeding season, male Ostriches which are black with white wing tips and tail end develop a bright coloured skin on their necks and thighs. The skin is red in east Africa and blue in the south and males in this condition are often referred to as red necks or blue necks, respectively.
Ostriches have been around for a long time and most experts think that they first evolved about 120 million years ago.