Gerenuk

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Gerenuk
Male
Two female gerenuk in the San Diego Zoo

Near Threatened  (IUCN 3.1)[1]
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Artiodactyla
Family: Bovidae
Subfamily: Antilopinae
Tribe: Antilopini
Genus: Litocranius
Kohl, 1886
Species:
L. walleri
Binomial name
Litocranius walleri
(Brooke, 1879)
     distribution of gerenuk (2008)[2]
Synonyms[3]
  • Gazella walleri (Brooke, 1879)
  • Lithocranius walleri Thomas, 1891

The gerenuk (

coat: the reddish brown back or the "saddle", and the lighter flanks, fawn to buff. The horns
, present only on males, are lyre-shaped. Curving backward then slightly forward, these measure 25–44 cm (10–17+1⁄2 in).

Taxonomy and phylogeny

The gerenuk was first

River Juba in southern Somalia" before giving them to Waller.[5] In 1886, Franz Friedrich Kohl proposed a new genus for the gerenuk, Litocranius.[6] The common name derives from the Somali name for the animal (gáránúug); the first recorded use of the name dates back to 1895.[7] It is also known as the "giraffe gazelle" due to its similarity to the giraffe.[8]

Two subspecies have been proposed, but these are considered to be independent species by some authors.[3][9][10][11]

  • L. w. sclateri (Northern gerenuk or Sclater's gazelle) Neumann, 1899: Its range extends from northwestern Somalia (Berbera District) westward to touch the Ethiopian border and Djibouti.
  • L. w. walleri (Southern gerenuk or Waller's gazelle) (Brooke, 1879): Its range extends through northeastern Tanzania through Kenya to
    Galcaio (Somalia). The range lies north of the Shebelle River
    and near Juba River.

In 1997

Gazella and Nanger (of Antilopini).[13]

Gazella

Blackbuck (Antilope cervicapra)

Gerenuk (Litocranius walleri)

Springbok (Antidorcas marsupialis)

Saiga (Saiga tatarica)

Oribi (Ourebia ourebi)

Description

Close-up view of a male. Note the white facial markings and the lyre-shaped horns.

The gerenuk is a notably tall, slender

sexually dimorphic. The tail, that ends in a black tuft, measures 25–35 cm (10–14 in).[10][14]

Two types of colouration are clearly visible on the smooth

dorsal parts (the back or the "saddle"), and the lighter flanks, fawn to buff. The underbelly and insides of the legs are cream in colour. The eyes and the mouth are surrounded by white fur. Females have a dark patch on the crown. The horns, present only on males, are lyre-like (S-shaped). Curving backward then slightly forward, these measure 25–44 cm (10–17+1⁄2 in).[14][10]

The gerenuk resembles the

cranial features, along with a two-tone colouration of the coat and strong thick horns (only in males).[15] However, there are also some features distinguishing it from the gerenuk, including major morphological differences in horns, horn cores, tail, postorbital area and basioccipital processes. The gerenuk has a longer, heavier neck and a shorter tail.[10] A finer point of difference is the absence of an inward-curving lobe in the lower edge of the ear (near its tip) in the gerenuk.[15] The subspecies of the gerenuk are similar in colouration; the southern gerenuk is the smaller of the two.[10] The Gerenuk stages of growth have a timespan from 4 months to 2.5 years: at four months, their shoulder height is about two-thirds of adult female, at six months their shoulder height is about three-quarters of adult female, at eight months their horn tips are clearly visible (about 1cm long), at one year their shoulder height is nearly equal to adult female but body more lightly built, their horns are slightly less than half ear-length, then curve, at two years their horns are about 1.5 times their ear length and the second curve becomes noticeable with the tips turning forwards, and finally at two and a half years the double curve in the horns are nearly completed. [16]

Ecology and behavior

The gerenuk is a diurnal animal (active mainly during the day), though it typically stands or rests in shade during the noon. Foraging and feeding is the major activity throughout the day; females appear to spend longer time in feeding. The gerenuk may expose itself to rain, probably to cool its body.[17] The social structure consists of small herds of two to six members. Herds typically comprise members of a single sex, though female herds additionally have juveniles. Some males lead a solitary life.[10]

Fighting and travel are uncommon, possibly as a strategy to save energy for foraging.[8] Both sexes maintain home ranges 3–6 km2 (1–2+1⁄2 sq mi) large, and might overlap. Those of males are scent-marked with preorbital gland secretions and guarded - hence these may be termed territories. The sedentary tendency of the antelope appears to increase with age.[11]

Diet

Gerenuks feeding

Primarily a browser, the gerenuk feed on foliage of bushes as well as trees, shoots, herbs, flowers and fruits.[18] It can reach higher branches and twigs better than other gazelles and antelopes by standing erect on its hindlegs and elongating its neck; this helps it reach over 2 m (6 ft 7 in) above the ground.[11] Acacia species are eaten whenever available,[11] while evergreen vegetation forms the diet during droughts.[14] The pointed mouth assists in extracting leaves from thorny vegetation.[11] The gerenuk does not drink water regularly.[18] Major predators of the antelope include African wild dogs, cheetahs, hyenas, lions and leopards.[10]

Reproduction

Gerenuk reproduce throughout the year. Females reach

gestation period is about seven months. They are born one at a time, weighing about 3 kg (7 lb) at birth. Offspring were produced through artificial insemination for the first time in 2010 at White Oak Conservation in Yulee, Florida. Four female calves were born, and one of the four was later inseminated successfully by White Oak and SEZARC (South-East Zoo Alliance for Reproduction & Conservation), creating a second generation of calves born from artificial insemination.[19] Gerenuk can live thirteen years or more in captivity, and at least eight years in the wild.[18]

References

  1. doi:10.2305/IUCN.UK.2016-2.RLTS.T12142A50190292.en
    . Retrieved 12 November 2021.
  2. ^ IUCN SSC Antelope Specialist Group (2008). "Litocranius walleri". IUCN Red List of Threatened Species. 2008. Retrieved 21 June 2012.
  3. ^
    OCLC 62265494
    .
  4. ^ a b Brooke, V. (1878). "On a new species of gazelle from western Africa". Proceedings of the Zoological Society of London: 929–930.
  5. ^ Sclater, P.; Thomas, O. (1898). "The gerenuk". The Book of Antelopes. Vol. 3. London: R. H. Porter. pp. 229–237.
  6. ^ Kohl, F. F. (1886). "Ueber neue und seltene antilopen des K. K. Naturhistorischen Hofmuseums" [About new and rare antelopes from the K. K. Natural History Museum]. Annalen des K.K. Naturhistorisches Hofmuseums (in German). 1 (1): 75–86.
  7. ^ "gerenuk". Merriam-Webster.com Dictionary. Retrieved 13 May 2020.
  8. ^
    ISBN 9780806131467
    .
  9. ISBN 9781421400938
    .
  10. ^
    ISBN 978-0-691-16717-6
    .
  11. ^
    ISBN 978-1-4729-1236-7
    .
  12. PMID 10381312
    .
  13. PMID 23485920
    .
  14. ^
    ISBN 9780520080850
    .
  15. ^
    ISBN 978-1-4081-8994-8
    .
  16. ^ Leuthold, W. (1978). On the Ecology of the Gerenuk Litocranius walleri. Journal of Animal Ecology, 47(2), 561–580. https://doi.org/10.2307/3801
  17. doi:10.1111/j.1365-2028.1978.tb00444.x
    .
  18. ^
    JSTOR 3801
    .
  19. ^ "One of our member institutions working with assisted reproductive techniques". Conservation Centers for Species Survival. Archived from the original on 2022-02-26. Retrieved 3 June 2013.

Further reading

External links

Wikimedia Commons has media related to Litocranius walleri.
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