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Addax nasomaculatusaddax

By Berke Altan

Geographic Range

Formerly occurred in desert and semidesert areas from Western Sahara and Mauritania to Egypt and Sudan. The current range reduced to desert regions in Northeastern Niger, North Central Chad, Northwestern Mali, Eastern Mauritania, Southern Libya, and Northwestern Sudan.

Habitat

The addax is not restricted to areas with free water, and is usually found within the desert or the surrounding stony country.

Physical Description

The addax is a sandy to almost white color during the summer, darkening to a grayish brown in the winter. White markings are present on the face, ears, belly, hips, and legs, and there is a black tuft of hair on the forehead. Horns are present on both males and females, average about 72 cm in length. They have approximately 1.5 to 3 spiral twists. The hooves are widely splayed as an adaption to travelling over desert sand. The addax head-body length is 150-170 cm, shoulder height is 95-115 cm, and tail length is 25-35 cm, with males being slightly larger than females.

  • Range mass
    60 to 125 kg
    132.16 to 275.33 lb
  • Range length
    150 to 170 cm
    59.06 to 66.93 in

Reproduction

Breeding can occur throughout the year, with population birth peaks in winter and early spring. Gestation lasts 257-264 days, and there is almost always one young born. The calf is weaned after 23-39 weeks. Males are sexually mature at about 24 months, females during their second or third summer.

  • Breeding interval
    Addax females give birth to as many as one young each year.
  • Breeding season
    Breeding may occur at any time of the year, but is most common during the spring.
  • Range number of offspring
    1 to 2
  • Average number of offspring
    1
  • Average number of offspring
    1
    AnAge
  • Range gestation period
    8.57 to 8.8 months
  • Range weaning age
    5.37 to 9.1 months
  • Average weaning age
    7.235 months
  • Range age at sexual or reproductive maturity (female)
    2 to 3 years
  • Average age at sexual or reproductive maturity (male)
    2 years

Lifespan/Longevity

Addaxes can live up to 25 years in captivity.

Behavior

The addax moves about the desert in herds of about 5-20 animals, and the herd is led by a dominant adult male. Males attempt to establish their own territory, trying to keep fertile females within these territories. A single male will mate with several females in his territory. Females establish a hierarchy of dominance, with the oldest animals ranking the highest. The addax is a "short leg" runner. It cannot achieve very high running speeds, allowing it to fall prey to faster predators.

Communication and Perception

Food Habits

The addax feeds on desert grasses and scrub. It searches great distances through the Sahara for sparse vegetation. The addax is the most desert-adapted of the antelopes. They spend most of their lives without drinking water; they receive enough moisture to survive from the vegetation they feed on.

  • Plant Foods
  • leaves
  • wood, bark, or stems
  • flowers

Economic Importance for Humans: Positive

The meat and the skin of the addax are prized by local people, who use the hides for shoes and sandal soles.

  • Positive Impacts
  • food
  • body parts are source of valuable material

Economic Importance for Humans: Negative

None

Conservation Status

Addax are heavily built, slow running antelopes that are easy prey for humans with modern weapons. Hunting has decreased and eliminated many resident populations in many parts of its original range. Tourists in four-wheel-drive vehicles also affect the animals by chasing them until they die of exhaustion. Recent droughts, desertification of savanna lands, and increasing human population have all contributed to the decrease of addax populations.

Contributors

Berke Altan (author), University of Michigan-Ann Arbor, Phil Myers (editor), Museum of Zoology, 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.

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.

diurnal
  1. active during the day, 2. lasting for one day.
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.

folivore

an animal that mainly eats leaves.

food

A substance that provides both nutrients and energy to a living thing.

herbivore

An animal that eats mainly plants or parts of plants.

iteroparous

offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).

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

sexual ornamentation

one of the sexes (usually males) has special physical structures used in courting the other sex or fighting the same sex. For example: antlers, elongated tails, special spurs.

social

associates with others of its species; forms social groups.

tactile

uses touch to communicate

temperate

that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle).

terrestrial

Living on the ground.

territorial

defends an area within the home range, occupied by a single animals or group of animals of the same species and held through overt defense, display, or advertisement

tropical savanna and grassland

A terrestrial biome. Savannas are grasslands with scattered individual trees that do not form a closed canopy. Extensive savannas are found in parts of subtropical and tropical Africa and South America, and in Australia.

savanna

A grassland with scattered trees or scattered clumps of trees, a type of community intermediate between grassland and forest. See also Tropical savanna and grassland biome.

temperate grassland

A terrestrial biome found in temperate latitudes (>23.5° N or S latitude). Vegetation is made up mostly of grasses, the height and species diversity of which depend largely on the amount of moisture available. Fire and grazing are important in the long-term maintenance of grasslands.

viviparous

reproduction in which fertilization and development take place within the female body and the developing embryo derives nourishment from the female.

year-round breeding

breeding takes place throughout the year

References

Alden, P. C., E., M. Schlitter, D.. 1995. National Audobon Society Field Guide to African Wildlife. New York: Alfred A. Knopf, Inc..

Nowak, R. 1999. Walker's Mammals of the World (Sixth Edition). Baltimore and London: Johns Hopkins University Press.

Smith, S. 1985. Atlas of Afica's Principle Mammals. Sandton and San Antonio: Natural History Books.

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