The flightless Ostrich (Struthio camelus) is the only species in the genus Struthio and in the family Struthionidae. The Ostrich is the tallest and heaviest living bird. Males are 2.1 to 2.75 m tall and weigh 100 to 130 (or even 150) kg; females are around 1.75 to 1.9 m tall and weigh 90 to 110 kg. The eyes are the largest of any terrestrial vertebrate, with a diameter of 5 cm. Its long, stout legs allow an Ostrich to cover a lot of ground quickly and can also serve as powerful weapons; each foot has a 10 cm sturdy flattened claw on the thick inner toe (uniquely among living birds, there are only two toes on each foot). The Ostrich is the fastest runner among birds. It can maintain a speed of 50 km/h for around half an hour and can sprint to 70 km/h with strides of 3.5 m, using its wings for balance at high speeds.
The male Ostrich is mostly pitch black, but the wings and tail are a sharply contrasting pure white; females are notably drabber. The Ostrich is one of the relatively few bird species that has a penis, which the male displays prominently during courtship.
Ostriches are found across much of the Sahel and eastern and southern Africa in a range of open habitats, from savanna to desert (in southern Australia there are some small populations of feral Ostriches from abandoned Ostrich farming operations). Ostriches do not require drinking water since they obtain sufficient water mainly from succulent plants. On hot days, they can allow their body temperature to rise to 42 C, reducing water loss through transpiration.
Outside the breeding season, Ostriches tend to live in small groups (although hundreds of Ostriches may congregate around water sources in the dry season). During the breeding season, birds form pairs or small harems. Males are territorial and engage in conspicuous courtship rituals. Multiple females may lay eggs in a single nest; a single nest may contain dozens of eggs, although only around two dozen can be incubated. Both the male and female incubate, with the more conspicuous male taking the night shift. Each egg weighs around 1.5 kg--enormous in absolute terms, but only around 1.5% of the adult female's weight. Eggs hatch together after around six weeks.
The idea that an Ostrich will bury its head in the sand in the face of danger is a myth, although when it feels trapped an Ostrich may sit down motionless with head and neck stretched on the ground in front of it in an apparent attempt to remain inconspicuous.
Ostriches produce many vocal and non-vocal sounds. They are omnivorous, but generally feed largely on plant material. The 14 m intestines allow them to eat many foods rejected by many other animals not equipped to extract enough of value from less desirable food items.
Ostriches have long been exploited by humans for their feathers, eggs, meat, and skin. At one time the Ostrich was common in most of Africa and southwestern Asia. Today, the range is considerably reduced and the subspecies that used to occur from the Syrian desert to the Arabian Peninsula was virtually extinct by 1941, having declined rapidly after World War I, with the last known record being a drowning individual in Jordan in 1966. There have been some efforts to reintroduce Ostriches to the Middle East.
(Folch 1992 and references therein)