Addax nasomaculatusaddax

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.