Ostriches are the tallest, heaviest, and fastest-running birds alive today. They also lay the largest eggs of any currently living birds. Native to Africa, these birds stick mainly to dry and arid grasslands or savannas, but some also live in deserts and mountainous regions. They belong to a group of flightless birds known as ratites, including emus, rheas, cassowaries, and kiwis. All of these birds, though now classified in separate orders, belong to the infraclass, Palaeognathae. Ostriches belong to the order Struthioniformes, within which scientists currently recognize two species, the Common Ostrich, Struthio camelus, and the Somali Ostrich, Struthio molybdophanes.
Ostriches are extremely tall birds. Males can reach heights between nearly 7 feet up to 9 feet, towering over all other bird species. Females range from a little over 5.5 feet tall to around 6.5 feet. The Common Ostrich generally weighs more than the Somali Ostrich, with males of the former reaching an average of 220 to 290 pounds. The North African subspecies of the Common Ostrich produces heavier males, with many individuals easily topping 300 pounds. The South African subspecies is much lighter, with some males averaging closer to 150 pounds.
An ostrich measuring 9 feet tall may be roughly 6 feet tall at the shoulder. Its neck measures approximately three feet in length, adding considerably to its overall height. The long, muscular neck and legs vary in color depending on the species or subspecies. The Somali Ostrich’s neck and legs are tinted blue. The Common Ostrich is divided into three subspecies. The North African subspecies has a bright, pinkish-red neck and legs. The East African subspecies, likewise, has a pink neck and legs, but lighter than that of the North African variety. The South African subspecies, also known as the Black-necked Ostrich, has a mostly light gray neck with a black base and light gray legs.
Ostriches, like most birds, exhibit sexual dimorphism. In addition to being taller and heavier, males of these species are more vividly colored than females. They have mainly black, fluffy feathers with white primary and tail feathers. Females and juveniles, meanwhile, have mostly brownish-gray feathers. Both sexes have huge eyes rimmed with primitive feathers that resemble long and luxurious eyelashes.
Ostriches lay creamy white eggs nearly 6 inches long and about 5 inches wide. These are the largest eggs of any bird species, but interestingly they are the smallest eggs relative to the size of the bird. Females lay their eggs in a communal nest. The eggs weigh approximately 3 pounds. Baby chicks are about 10 inches tall and weigh between about 2 and 2.5 pounds. They grow at a rate of 12 inches per month and are close to their full height by the time they reach about six months of age. Ostriches reach sexual maturity around three to four years of age, with birds in captivity maturing more quickly.
Ostrich Speed and Agility
Ostriches run incredibly fast, but their real strength lies in their stamina and their ability to use evasive maneuvers. An ostrich can reach speeds of at least 43 miles per hour, 70 kilometers per hour, in short bursts. That compares to the top speed of a sprinting zebra or African wild dog.
Ostriches can’t run nearly as fast as a cheetah at its top speed of roughly 76 miles per hour, but cheetahs can only maintain that speed for about a minute. Ostriches, on the other hand, can maintain speeds of up to 34 miles per hour over long distances, sometimes running at that speed for half an hour or more.
The stride of an ostrich measures 10 feet or more in length. It has specially adapted spring-like feet that absorb shock and help propel the bird forward as it runs. Ostriches have only two toes on their feet, as opposed to all other birds, which have three or four. Their main toe is much larger than the small outer toe, which gives the foot a sort of hoof-like structure especially good for running.
Evasive Maneuvers and Defense
Speaking of those giant toes, ostriches have sharp nails on their long, inner toes that they can use to fight predators. They have the longest, strongest legs of any bird, giving them an incredible reach and the ability to kick opponents ferociously.
Ostriches cannot fly, but they have strong wings that span approximately 6.5 feet. They use these for balancing and shifting directions when they run. They can also use these massive wings much like the parachutes used by drag racers, to help them slow down or stop quickly.
Of course, one of the most effective defensive advantages this impressively tall bird has is its ability to see what is going on around it. These birds, already super tall, have extremely long necks and large eyes, giving them the ability to rise up and survey everything around them. Even a well-camouflaged cheetah may have a hard time sneaking up on an alert ostrich. Being able to observe the world from an elevated perspective gives these birds a greater chance for a head start against predators that can outrun them over short distances.
Habitat and Distribution
Ostriches are native to Africa. They live primarily in the arid savanna regions and the desert. The two subspecies of ostriches currently recognized mainly occupy separate regions, their ranges overlapping only in small regions in eastern Africa.
Somali Ostrich Distribution
The Somali Ostrich, Struthio molybdophanes, has a much smaller distribution. It ranges over most of Somalia, southern Djibouti, central Kenya, and portions of Ethiopia. This species lives not only in arid and semi-arid grasslands but also in shrublands and even in forests.
Common Ostrich Distribution
The Common Ostrich, Struthio camelus, has a much larger range. It inhabits multiple regions with each subspecies separated from one another. Two of the subspecies overlap just slightly in eastern Africa, while the third is completely separate, ranging in southern Africa.
The subspecies known as the North African Ostrich, Barbary Ostrich, or Red-necked Ostrich, Struthio camelus camelus, once lived all across a wide swath of dry, arid grasslands known as the Sahel. As recently as 1992, the range of this subspecies stretched from Senegal and Mauritania, on the west coast of Africa, all the way to the Red Sea in the east. It also included locations in northern Africa such as grasslands in Egypt and Morocco. However, over the past few decades, the range of this subspecies has diminished to disconnected patches across just a handful of countries, including Chad, Cameroon, the Central African Republic, and Senegal. The North African Ostrich has been reintroduced in the northern Africa countries of Tunisia and Morocco.
Another subspecies, known as the Masai Ostrich, also known as the East African Ostrich or the Pink-necked Ostrich, Struthio camelus massaicus, lives to the southwest of the Somali Ostrich. This subspecies lives in Kenya, Uganda, and Tanzania, sticking mainly to the dry and arid savanna. They also live in shrublands, deserts, and rocky, mountainous terrain.
The final living subspecies of the Common Ostrich, known as the South African Ostrich, the Cape Ostrich, or the Black-necked Ostrich, Struthio camelus australis, ranges far south of the others. Its range extends from southern Angola and Zambia south through Namibia, Botswana, Zimbabwe, eastern Mozambique, and South Africa. This subspecies has also been introduced and ranges throughout parts of Australia.
Diet and Feeding Habits
Ostriches are omnivores with herbivorous preferences. They eat mainly plants, consuming green and leafy grasses whenever possible. Their main diet also includes leaves from trees and shrubs, berries and other fruits, seeds, roots, bulbs, and succulents. These hardy birds can go for several days without drinking water, as they get most of their hydration through the plants they eat.
Researchers observing ostriches from both subspecies on an Ethiopian preserve noted that plants accounted for roughly 75 percent of their diet. In addition to grasses and other plant material, the birds often ate leaves and even bark from shrubs and trees such as the acacia, desert date, and willow-leaved shepherd tree.
The plants preferred by ostriches differ in wet seasons as compared to dry seasons. In wet seasons, the birds are particularly drawn to green grasses and growing, tender shoots. Ostriches tend to gather together more during the wet season and spread out more in the dry season, when food is harder to find. In the dry season, the birds give higher preference to the green leaves, pods, and fruits they can find on trees and shrubs.
Ostriches consume other foods, too, including a wide variety of insects. They also eat small mammals, lizards, and snakes. Although they have strong beaks, they do not have teeth, so they swallow these animals whole. Ostriches sometimes dine on carrion left by other animals. They even sometimes break their own eggs and eat them. And ostriches practice coprophagia, occasionally eating their own feces and that of other animals.
Ostrich Digestion Made Simple
As mentioned, ostriches do not have teeth, but they do have a specially adapted digestive tract made for breaking down their tough, fibrous diet. Let’s take a look at the adaptations that help ostriches digest their food.
Ostriches have a strong esophagus that can handle tough foods and other objects. They gulp down food and store it in the pouch-like esophagus until they get a bolus large enough that they want to swallow. Only then do they move the food into their stomach.
One Stomach or More?
Scientists refer to ostriches as monogastric herbivores because they mainly eat plant material and they have one large stomach, divided into parts. The upper part of the stomach, known as the proventriculus or glandular stomach, secretes gastric juices which begin to break down the bolus of food. Once the material is softened, it moves to the lower, highly muscular portion known as the ventriculus or gizzard.
Ostriches swallow rocks, pebbles, sand, and even other objects such as broken glass. These hard objects travel down their throat, through the proventriculus, and into the gizzard. There, the rocks and other objects grind together under pressure from the muscular organ, breaking down tough plant material even better than teeth could.
Intestines Made for Fermentation
Ostriches have very long intestines, measuring up to about 50 feet in length. Their small intestines are significantly shorter than their large intestines, especially as they mature. In fact, when researchers measured the large intestines of mature wild ostriches, they accounted for 50 percent or more of the total length of the small and large intestines combined. That’s much more than most other birds. The large intestine of an emu, for instance, accounts for less than 10 percent of its total intestinal length. Emus are insectivores, while ostriches live mostly on highly fibrous plant material which takes longer to break down.
Ostriches also have two long sacs on either side of their large intestine that store and ferment food. These sacs, called ceca or caeca, can be up to nearly five feet long. The bacteria in the ceca and large intestines of an ostrich help it to break down plant fibers very efficiently.
An Unusual Cloaca
Ostriches defecate in an unusual way because the anatomy of their cloaca differs from most other birds. The ostrich cloaca consists of just two compartments, the proctodeum and the coprodeum. The coprodeum follows the colon and is preceded by a pair of sphincters. The proctodeum comes next, just before the bird’s vent, or anus. Ostriches do not have a urodeum, as most birds have for collecting urine. Instead, the ostrich collects urine in the proctodeum and releases it separately from its feces. The bird’s feces can then move down from the coprodeum and through the proctodeum to be excreted. Coprophagic ostriches sometimes consume their own pellet-shaped poop to maximize nutrients and water content, thus increasing their ability to thrive in dry and challenging environments.
Ostriches have long struggled to maintain their place in Africa. They were exploited for their feathers by the fashion industry beginning more than 200 years ago, and have been hunted for everything from their meat and eggs to their skin and fat. Ostrich numbers are currently in decline.
Although the International Union for Conservation of Nature Red List of Threatened Species lists the Common Ostrich as a species of least concern, the North African subspecies, in particular, needs help badly. Its range and distribution have shrunk rapidly in recent decades. Workers with Sahara Conservation are currently working to save the subspecies, breeding North African Ostriches on preserves in Niger and helping to reintroduce them in places like Morocco and Tunisia. Some scientists want the subspecies to be reclassified as a separate species so that more concentrated efforts to save it can be made.
The Somali Ostrich population is also declining rapidly due to habitat degradation and excess hunting. The IUCN Red List categorizes this species as vulnerable. The subspecies is currently farmed in locations such as Kenya for its meat, feathers, eggs, and skin.
Some people say that ostriches are akin to dinosaurs, and these giant birds are certainly impressive. They are the tallest and heaviest birds on the planet, and they can run faster than any other bird and most mammals. These birds feature among the most unique species in the world. One cannot help but marvel at their speed and their size. Unfortunately, like so many other species, ostriches face challenges in the form of exploitation and habitat degradation. Humans must act now if we hope to preserve these birds for the future.
The photo featured at the top of this post is © John Michael Vosloo/Shutterstock.com
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