OSTRICH: CHARACTERISTICS, REPRODUCTION, FEEDING, BEHAVIOR - BIOLOGY - 2025

The ostrich (Struthio camelus) is a flightless bird that belongs to the Struthionidae family. This species is the largest living bird, the male reaching 2.75 meters in height and reaching a weight of 150 kilograms.

The coloration of their plumage varies according to sex. Males are generally black, with white tail and wingtips. As for the females, they are usually brown or gray tones. Another variation, in terms of color, is presented by the skin. This can be from white to red-orange.

Ostrich. Source: Harvey Barrison from Massapequa, NY, USA

This bird is native to the African continent, where it lives in open areas and in sandy and arid habitats. It is a herbivorous animal, which also tends to consume some animals, such as locusts and rodents, and carrion.

The ostrich has a very particular behavior when faced with the threat of a predator. Both youngsters and adults, to avoid being spotted by the threatening animal, throw themselves on the ground, with their face and neck stretched out. Thus, from afar they can look like a mountain of sand.

This defense habit may have given rise to the popular belief that this wild bird buries its head in the ground.

General characteristics

Male Masai ostrich (Struthio camelus massaicus) Source: Nicor ​​/ Public domain

Legs

The ostrich has a unique structure in the legs, which have evolved to adapt to the desert environment. These have only 2 fingers, called the third and fourth. Between the fingers there is a metatarsophalangeal pad, where the interphalangeal ligament is located.

The third toe is robust, well developed, and forms an angle of approximately 34 ° with the fourth toe. In addition, it has 4 phalanges, with the first of these being larger than the rest.

As for the fourth finger, it is short and its constitution is less strong than that of the third. It has 4 phalanges, although sometimes it could present a fifth, but it is degenerated.

The ostrich tarsus is the largest of all living birds. Its length is 39 to 53 centimeter. The reduction in the number of fingers is a body adaptation that contributes to the animal being able to run quickly.

The ostrich can reach a speed greater than 70 km / h and in a single step it can cover 3 to 5 meters.

Pads

The African ostrich is a large bipedal animal that can move at great speed. According to the studies carried out, the distribution of plantar pressure during gait or walking is concentrated below the third toe, while the fourth toe contributes to the balance of movement.

Thus, the brief, severe impact that occurs while running could lead to phalangeal dislocations and soft-tissue damage to the legs. Another factor that affects this part of the body is vibration and negative acceleration, caused by the reaction force of the ground.

This is why the toe pad has characteristics that promote shock absorption. The researchers argue that, based on biomechanical characteristics, these structures absorb energy and reduce vibration.

In this way, it helps to maintain the stability of the animal and in the protection of the plantar tissue.

Lungs

The ostrich lung has characteristics that are present in other groups of birds. For example, this African bird lacks interparabronchial septa, has morphometric refinement, and its atria are shallow. These particularities are typical of small flying birds.

Also, the neopulm is underdeveloped, as in flying ratites. As for the bronchial system, its large size could explain the changes in airflow in the respiratory tract, which occur from rest to wheezing.

In addition, the size of the bronchi could be the reason for the organ's insensitivity to blood acid-base imbalance during sustained panting in a situation of heat stress.

These morphometric and morphological characteristics are the response to the achievement and maintenance of high aerobic capacities and long panting, without the ostrich experiencing respiratory alkalosis.

Size

Struthio camelus is the largest living bird. The adult male could be 2.75 meters tall and weigh more than 150 kilograms. As for the female, it is usually smaller than the male.

During the first year, the young grow about 10 inches per month. Thus, when they are one year old, the ostrich weighs around 45 kilograms. Once it reaches sexual maturity, between 2 and 4 years, the male measures between 2.1 and 2.8 meters, while the length of the female ranges between 1.7 and 2 meters.

Coloration

Ostrich skin can range from shades of gray to deep pink. The male generally has a black coat, with white feathers on the tail and wings.

The female and the young are grayish brown. As for the head and most of the neck they are almost bare, being covered by a fine down. The limbs are not covered with feathers, so the skin tone stands out.

The feathers do not have the hooks that attach the outer feathers of flying birds. Due to this, they are fluffy and soft and fulfill the function of thermal insulation.

Head

The head of the Struthio camelus is small and stands at a height of 2.8 meters above the ground. It has a wide and short bill, measuring between 12 and 14.3 centimeters. Their eyes are brown and large, with a diameter of 50 millimeters. In addition, they have thick black eyelashes.

Wings

The ostrich has a flat sternum, lacking a keel. This extension of the chest bone is what provides the area for the flight muscles to anchor in the case of flying birds.

The wings have a wingspan of 2 meters. Although this bird does not fly, the wings serve several functions. For example, they use them to cover the bare skin of their limbs and flanks, to conserve heat, or they leave them uncovered to release it.

They also act as stabilizers, giving the bird greater maneuverability when running. Thus, they participate in zigzag and turn movements.

Adaptations to the environment

The ostrich can tolerate a wide range of temperatures. In most of its habitat, temperatures can vary, reaching up to 40 ° C. The animal can regulate its body temperature through various physical and metabolic adaptations.

Physical adaptations

Ostriches (Struthio camelus). Source: Nevit Dilmen / Public domain

Struthio camelus performs some behavioral actions, which allow thermoregulation. Among these is the variation of the position of the feathers. In very hot situations, they contract the muscles, thus lifting the feathers. This puffiness increases the air space above the skin.

This area provides insulation of approximately 7 centimeters. Also, the bird exposes the thermal windows of its skin, where it has no feathers. In this way, it improves radiative and convective loss, in times of stress caused by heat.

Also, to refresh its body, the ostrich can seek shelter under the shade of a tree.

In the event that the external temperature drops, the ostrich flattens its feathers, thus conserving body heat through insulation. This behavior compensates for the loss of water caused by skin evaporation. Likewise, it can also cover its legs, reducing heat loss to the outside.

Internal adaptations

When the ambient temperature is lower than body temperature, the ostrich lowers its body surface temperature. Thus, heat loss only occurs in 10% of the total surface.

Another thermoregulatory mechanism developed by the ostrich is the known selective cooling of the brain. In this, the temperature of the blood reaching the brain is controlled, depending on the external conditions. Heat exchange occurs through the ophthalmic vascular network and the cerebral arteries.

Habitat and distribution

Distribution of the ostrich (Struthio camelus) in Africa. Source: Brion VIBBERs / Public domain

Distribution

Struthio camelus occupied the north and south of the Sahara, southern African rainforest, southern eastern Africa and a large part of Asia Minor. However, many of these populations are currently extinct. Such is the case with Scsyriacus, which lived in the Middle East, but was possibly extinct since 1966.

The ostrich is found in a large part of Africa, with a distribution that includes Mali, Mauritania, Niger, Sudan and Chad. It also lives in Ethiopia, Kenya, Eritrea, Uganda, Angola, Tanzania, Namibia, Zambia, South Africa, Zimbabwe, Botswana, and Mozambique.

Habitat

These birds prefer open areas, arid and sandy habitats. Thus, they can be located in the savannas and the Sahel of Africa, an ecoclimatic region of transition between the Sahara desert, in the north and the Sudanese savanna, to the south.

As for the Southwest African area, they live in semi-desert ecosystems or in the desert. Some of the environments most frequented by ostriches include forests, plains, bushes, and dry grasslands. Generally, their home range is near bodies of water.

Taxonomy and classification

- Taxonomy

-Animal Kingdom.

-Subreino: Bilateria.

-Filum: Cordate.

-Subfilum: Vertebrate.

-Infrafilum; Gnathostomata.

-Superclass: Tetrapoda

-Class: Birds.

-Order: Struthioniformes.

-Family: Struthionidae.

-Gender: Struthio.

-Species: Struthio camelus.

- Subspecies

Struthio camelus australis

The blue-necked ostrich inhabits southwestern Africa. Thus, it can be found in South Africa, Zambia, Namibia, Zimbabwe, Botswana, and Angola and Botswana. Also, it lives south of the Cunene and Zambezi rivers.

Both the male and the female have gray legs and necks, instead of the reddish hues of the other subspecies.

Struthio camelus camelus

The red-necked ostrich is common to northern and western Africa. It is the largest subspecies, reaching 2.74 meters in height and weighing around 154 kilograms.

It has a rosy red neck and, while the male's plumage is black and white, the female's is gray. Regarding the distribution of the Barbary ostrich it goes from the northeast to the west of Africa.

Struthio camelus massaicus

The Masai ostrich is found in East Africa. In relation to the coat, the male has a black coloration, with white tail and wingtips. The neck and the extremities are pink. For its part, the female has grayish brown feathers and its legs and neck are white.

Struthio camelus syriacus

The Arabian ostrich is an extinct subspecies, which lived, until the middle of the 20th century, in the Near East and on the Arabian Peninsula.

State of conservation

Historically, the North African ostrich has been exposed to various threats that endanger the stability of its populations. In recent years, this situation has worsened.

With the exception of a few small savanna populations, this bird has completely disappeared from its extensive Saharan-Sahelo range. Due to this situation, the subspecies is currently included in Appendix I of CITES and appears on the IUCN Red List as Least Concern.

In addition, some international animal protection organizations consider that it is in danger of becoming extinct. Thus, this African bird is part of a project of the Sahara Conservation Foundation.

The intention of this organization is to create and implement strategies aimed at preventing the extinction of this subspecies and restoring lost communities in the Sahel and the Sahara.

- Threats

The main threat to the North African ostrich is indiscriminate hunting. The capture of this animal is due to the fact that its skin, meat and feathers are sold in various markets. In some regions, the meat of this bird is considered a delicacy, as well as being an excellent source of iron, protein and calcium.

Another highly valued by-product is their eggs. Also, fur and feathers have been part of fashion, which led this animal to be very close to extinction, during the 18th century.

Currently the use of ostrich plumage as a fashion item has declined, but its fur is still used. This has a high resistance, which is why, among other things, it is used in the manufacture of clothing.

Perhaps one of the best known uses of feathers is in the production of feather dusters, which have been manufactured worldwide since 1900. The attractiveness of plumage is that they produce a static charge that allows dust to adhere. In addition, they are durable, washable and do not suffer damage during the process of making the cleaning article.

- North African Ostriches Recovery Project

This project, belonging to the Sahara Conservation Foundation, provides the research support, economic and technical resources necessary for the restoration in the wild of the ostrich, in the Niger region.

Thus, the main objective is the captive production of birds, to later be returned to their natural habitat. Along with this, it has awareness plans, aimed at the local community, where the importance of the conservation of this subspecies is highlighted.

- Reintroduction projects

Africa

The process of reintegration of the North African ostrich has started in Niger and north of the Sahara. In Morocco, they were introduced into the Souss-Massa National Park. In Tunisia, there are the Dghoumès National Park and the Sidi Toui yen National Park.

Asia

The North African ostrich is the closest subspecies of the extinct Arabian ostrich, which inhabited western Asia. Studies of the mitochondrial DNA (mtDNA) of both animals confirm their close relationship.

Because of this, the African subspecies was considered suitable to populate those areas where the Arabian ostrich used to live. For this reason, in 1994 some North African ostriches were successfully introduced into the Mahazat as-Sayd protected area in Saudi Arabia.

Reproduction

Female African ostrich with 2 chicks. Source: Lip Kee Yap / Public domain

The reproductive life cycle begins once the ostrich reaches sexual maturity. This can occur between 2 and 4 years, although females usually mature about 6 months before the male. The mating season begins in the first months of the dry season.

The females in heat are grouped in a harem, where between 5 and 7 ostriches coexist. The males fight each other for the right to join with them. The paddles include loud hisses, hisses and roars, accompanied by displays of feathers.

Ostriches couple with their chicks. Source: Susann Eurich / Public domain

To woo the female, the male vigorously flaps his wings, touching the ground with his beak and pretending to clean the nest. Later, while the female runs with her wings lowered around her, the male makes a circular motion with his head, causing it to fall to the ground.

Once on the ground, copulation occurs. The dominant male can mate with all the females in the harem, but only forms a group with the group leader.

The male builds the nest, digging a depression in the ground with his legs. This is about three meters wide and between 30 and 60 centimeters deep.

Incubation

Although there are several females in the harem, the dominant one lays her eggs first and then the others do. Between 15 and 20 eggs can be found in a nest. When covering them for hatching, the group leader can discard those that belong to the weaker females.

Ostrich eggs are the largest among living oviparous species. It measures approximately 15 centimeters long and 13 centimeters wide. In relation to weight, it is around 1.4 kilograms.

To incubate them, the female does it during the day and the male at night. This behavior is favored by the coloration of the plumage of both. During the day, the female's brown hue blends in with the earth, while at night, the male's dark coat is almost undetectable.

Regarding the incubation period, it lasts between 35 and 45 days. When the young are one month old, they can accompany the parents in their foraging activities. At the end of the first year, the youngster is the height of the adult.

Feeding

The ostrich is a herbivorous animal, although it can occasionally eat carrion and some animals. Their diet is based on seeds, flowers, leaves, herbs, bushes and fruits. Among the animals that make up its diet are rodents, lizards and lobsters, among others.

It is a selective and opportunistic bird that takes plant species based on their habitat and the time of year. When foraging, it tends to graze and eat whatever it can get in that area.

Also, due to its height, it has access to fresh branches and fruits that are several meters above the ground. This offers it a great advantage over other smaller animals that live in the same area.

In relation to water intake, Struthio camelus can survive several days without consuming water. However, as a result, they could lose up to 25% of body weight.

To make up for the lack of water sources, due to the strong droughts typical of the environment where it resides, this bird takes advantage of the water contained in the plants.

The digestion

Having no teeth, they swallow pebbles that act like gastroliths to grind food in the gizzard. When eating, the ostrich fills its esophagus with food, forming the food bolus.

Bacteria that contribute to the degradation of the ingested material are not involved in this first phase of the digestive process. Then, the bolus reaches the gizzard, where there are various stones that act as gastroliths, grinding the food.

This structure can weigh up to 1,300 grams, of which about 45% could be pebbles and sand. The process continues in the stomach, which is divided into three chambers. This African species lacks a gallbladder and the cecum measures about 71 centimeters.

Behavior

Ostriches have diurnal habits, but could be active on clear nights. The maximum peaks of activity occur very early in the day and in the afternoon. They live in groups of 5 to 50 animals and generally graze in the company of other animals, such as zebras and antelopes.

The territory of the male ostrich has an area between 2 and 20 km2. However, during the mating season, flocks can occupy territories of 2 to 15 km2.

Group size can vary, according to reproductive behavior. Thus, outside the mating season, the adult groups are made up of 5 to 9 ostriches.

In general, the Struthio camelus. it is an animal that rarely makes calls. Oral communication increases in the mating season, when the male hisses and growls, trying to impress the females.

Defending

Due to the advanced development of its senses of hearing and sight, this bird can detect its predators, among which are lions, from afar.

When chased, the ostrich can run at more than 70 km / h and keep speed constantly at 50 km / h. However, he sometimes prefers to hide from the threat.

For this, he lies on the ground, putting his head and neck on the ground. In this way, from afar, it appears to be a mountain of earth. In the event that it is cornered by the predator, it can give powerful kicks, causing serious damage to the aggressor, including death.

References

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