We all know ostriches (Struthio camelus) and have no doubt all been gladdened at the sight of these impressive birds in their wild habitat. There is much about them that is fascinating – for example, did you know that ostriches are among the scant three percent of all birds in which the males have penises? Not just any old penis, but a large, dense, cartilaginous phallus, powered by lymph rather than blood. The formidable organ is pushed out of the body cavity in order to mate.
(If you are wondering how the other 97% of birds do it, they mate by “cloacal kiss”.)
Photo: Male ostrich – Toronto Zoo
The sternum in flighted birds has a prominent keel from which the large pectoral muscles originate, but flightless birds such as the ostrich do not need the pectoral muscles to fly and therefore do not need a keel. Birds without such keels are called ratites. Other examples of ratites are the emus, cassowaries, greater rheas and kiwis.
Flight is a great way to avoid predators, but it’s “energetically expensive”. So ratites rely on another survival strategy, namely getting really big so fewer things can attack and eat them.
You probably know that the ostrich is the largest and heaviest bird on earth, standing up to three meters tall and weighing in at over 100 kg.
Their weight means of course that they cannot fly to escape danger. Instead, ostriches are great runners and are able to reach speeds of up to 70 km per hour – one stride can be five meters long. Their long, strong legs have two clawed toes, rather than the three or four toes found in most birds. Having only two toes helps them to reach these high speeds.
Ostrich feet – Pinterest
When an ostrich senses danger and cannot run away from the threat, it will flop down and remain still with its head and neck flat on the ground, in an attempt to blend in with the ground and escape detection. This tactic gave rise to the misconception that ostriches bury their heads in the sand.
However, when an adult ostrich is threatened, it attacks with its clawed foot and can deliver a kick powerful enough to kill a lion. This, together with their speed, makes them formidable foes. For this reason many farmers keep ostriches to defend their properties from intruders.
Ostriches have long necks, prominent large eyes (the largest eyes of any land animal) and beautiful long eyelashes. Long necks and excellent vision help them see for great distances, allowing them to keep an eye out for predators.
As ostriches are unable to fly, their feathers are structurally different from those of flying birds, which have tiny hooks to lock them together during flight. Ostrich feathers are fluffy and this helps them regulate their temperature.
The wings are thus more for show than function; they carry the beautiful white feathers that contrast so effectively with the black body feathers of the male. During courtship, the male’s neck and legs become flushed with red, and he uses his dramatic colouring to attract the drab brown female. He sinks slowly to the ground and begins to wave and shake the feathers of first one wing and then the other while moving his tail up and down. He then gets up and moves toward the female, holding his wings out and stamping as he approaches her. By this time the female is mightily impressed, crouches down and allows the male to mate with her.
Ostrich society is fascinating. The males each occupy and defend a territory – the so-called territorial male. There is also a dominant female, called the “alpha” or “main hen”. The dominant pair share the tasks of incubating the eggs and caring for the chicks. The nest is little more than a shallow depression scratched in the sand by the male.
Although the dominant pair stay together for life, they are by no means exclusive. The territorial/dominant male may mate with other females from the flock which then lay their eggs in the same nest as the main hen’s eggs, so it becomes a communal “egg dump”. The main hen lays about seven to ten eggs at a time, but she takes care to position her eggs in the centre of the nest to make sure they have the best chance of hatching. Communal laying has advantages for an ostrich flock: overall, more eggs hatch successfully in a communal nest than if each female ostrich had her own nest to incubate and protect. Usually the drab-coloured and well-camouflaged main hen takes incubation duty during the day; the black-plumed male takes over and incubates at night, during which time he is equally well-camouflaged.
Ostrich eggs are the largest eggs in the world of birds. One egg is the equivalent of about 24 chicken eggs.
Ostrich males are exemplary fathers. They take care of the chicks once they hatch. If a chick-rearing male comes across another ostrich father, they will do battle and the winner will take both sets of chicks. A possible reason behind this chick stealing is that having more babies around increases the chances that the father’s own offspring will be spared should a hungry predator come along.
Ostrich male with chicks – Londolozi Blog
Throughout the ages, the beautiful fluffy ostrich feathers have been worn by royalty, adorned the helmets of medieval knights, and festooned the elaborate hairdos of ladies. In the late 18th century, the hat industry turned the hunting of birds for their feathers into a major global enterprise.
Ostrich plumes were particularly prized. South Africa turned to the commercial farming of ostriches for their feathers. It quickly became a profitable industry; so valuable were ostrich plumes that in the early 20th century, they ranked fourth on the list of South African exports—after gold, diamonds, and wool. Then practically overnight the bottom dropped out of the feather market – due apparently to the invention of the motor car. Early cars had no roof or windshield, and women passengers found the feathers were being stripped from their hats and blown away.
Ostriches were once found in the wild all over Africa but nowadays they occur mainly in protected areas in southern Africa. They are now farmed mainly for their meat and skins.