Oryx dammahscimitar-horned oryx

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Geographic Range

The Scimitar-horned oryx is found in the desert to semidesert region of Africa known as the "Great Steppe." This area is a strip of arid grassland extending from Senegal to central Sudan, which borders the southern edge of the Sahara Desert.

Habitat

The Scimitar-horned oryx is found in barren steppes of desert to semidesert environments.

Physical Description

The Scimitar-horned oryx, like other oryxes, has a black and and white face mask. However, in this species the black tends to fade to a brownish color. Their basic color is white with rusty brown necks and chests. Soms specimens have brown bands on their flanks along with a rusty brown spot outlined on the thigh. Like all orxyes, calves are born with yellow coats and lack distinguishing marks which appear later in life. The Scimitar-horned oryx is average in size compared to the larger East African oryx or the smaller Arabian oryx. Average length is 5.5 ft (1.7 m) with a shoulder height of about 3.8 ft (1.2 m)and an average weight of 148 lbs . It is the only oryx whose horns curve backwards. The horns average about 40 inches (1 m), but lengths of 50 inches (1.2 m) or more have been recorded. Both sexes have horns and, like other oryxes, the female's tend to be more slender.

  • Average mass
    200 kg
    440.53 lb
  • Average mass
    177500 g
    6255.51 oz
    AnAge

Reproduction

Courting is done through the means of a mating circle. During this ritual, the male and female stand parallel to one another facing opposite directions. They then circle around one another until the cow allows the male to mount from behind. HOwever, if the female is not ready to mate, she can run away and circle in the reverse direction. Once the female oryx is impregnated, gestation lasts between 8 and 8.5 months. There is only one calf per birth, weighing an average of 20 to 33 lbs (9 to 15 kg).

  • Key Reproductive Features
  • gonochoric/gonochoristic/dioecious (sexes separate)
  • sexual
  • Range number of offspring
    1 (low)
  • Average number of offspring
    1
  • Average number of offspring
    1
    AnAge
  • Range gestation period
    8.07 to 8.53 months
  • Average age at sexual or reproductive maturity (female)
    Sex: female
    639 days
    AnAge
  • Parental Investment
  • post-independence association with parents

Lifespan/Longevity

  • Average lifespan
    Status: captivity
    27.5 years
    AnAge

Behavior

Orxyes usually travel in herds ranging in size from 2 to 40. Most often in any particular herd there will be a dominant or alpha bull. Usually these bulls provide the guidance for the herd as to when it will move and where. They retain tight control over marching formation and chase down any stragglers with persistence. Unlike other oryxes, solitary male Scimitar-horned oryxes are seldom seen. Male oryxes often engage in fights. However, these confrontations are well-choreographed and seldom end in bloodshed, unless there is strong competition for vital resources. Fencing matches follow a similar pattern as the mating circles, with the inferior male lowering his head to the dominant one, much like the cow would to the male.

Communication and Perception

Food Habits

The Scimitar-horned oryx is herbivorous, feeding on annual grasses, herbs, juicy roots, buds, and when water is scarce, fruits and vegetables. Like most inhabitants of arid environments it is subject to unpredictable and variable amounts of precipitation. Because of their great nomadic ability, the Scimitar-horned oryx will travel many miles in search of new new green grass which sprouts up quickly after sudden down pours. Though they tend to stay in small groups of about 40, when food is scarce and concentrated they can form herds of more than a hundrend.

Economic Importance for Humans: Positive

This oryx was used as a food source in the past, but now its most valuable contribution is probably its place in ecotourism. Both Africa and the United States are profiting greatly from the recent rise in this new form of tourism.

Conservation Status

Though the Scimitar oryx's range has been greatly reduced, especially in the north, their numbers have stayed relatively high thanks to the large numbers living in captivity. Several large game preserves, mainly in Texas, have instigated successful programs for breeding the Scimitar-horned oryx. However, its habitat is being destroyed and reintroduction of large populations may prove difficult.

Other Comments

Several physiological abilities unique to desert oryxes enable them to live nomadic lifestyles in near-desert environments. Under conditions of water stress these oryxes can raise their body temperature up to 116 degrees F (46.6 C). With functioning metabolism at these high temperatures, less water is needed for evaporation in order to help conduct heat away from the body. This reduced evaporation of bodily fluids helps these oryxes go long periods without water. In times of ample supply, oryxes can also use fluid loss through urination and feces, to lower their body temperatures below 97 F (36 C) at night, thus allowing them more time before maximum body temperature is reached the following day.

Another anatomical adaptation allows the oryx to tolerate high temperatures that would be lethal to most mammals. They have a network of fine blood vessels that carry blood from the heart to the brain. These blood vessels travel close to the nasal passage, allowing cooling of up to five degrees F of the blood before it is pumped to the brain, one of the most heat sensitive organs of the body.

Contributors

Hugh Johnson (author), University of Michigan-Ann Arbor, Dea Armstrong (editor), University of Michigan-Ann Arbor.

Glossary

Ethiopian

living in sub-Saharan Africa (south of 30 degrees north) and Madagascar.

World Map

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

chaparral

Found in coastal areas between 30 and 40 degrees latitude, in areas with a Mediterranean climate. Vegetation is dominated by stands of dense, spiny shrubs with tough (hard or waxy) evergreen leaves. May be maintained by periodic fire. In South America it includes the scrub ecotone between forest and paramo.

chemical

uses smells or other chemicals to communicate

desert or dunes

in deserts low (less than 30 cm per year) and unpredictable rainfall results in landscapes dominated by plants and animals adapted to aridity. Vegetation is typically sparse, though spectacular blooms may occur following rain. Deserts can be cold or warm and daily temperates typically fluctuate. In dune areas vegetation is also sparse and conditions are dry. This is because sand does not hold water well so little is available to plants. In dunes near seas and oceans this is compounded by the influence of salt in the air and soil. Salt limits the ability of plants to take up water through their roots.

dominance hierarchies

ranking system or pecking order among members of a long-term social group, where dominance status affects access to resources or mates

endothermic

animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.

motile

having the capacity to move from one place to another.

native range

the area in which the animal is naturally found, the region in which it is endemic.

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

social

associates with others of its species; forms social groups.

tactile

uses touch to communicate

References

Grizmek, V. 1990. Grizmek's Encyclopedia of Mammals, Vol. 5. New York: McGraw-Hill.

Land, T. 1983. Return of the Unicorn. The New Leader, 66.

Skirka, A. 1971. African Antelope. New York: Winchester Press.