dcsimg

Brief Summary

    Gerenuk: Brief Summary
    provided by wikipedia

    The gerenuk (/ˈɡɛrɪnʊk, ɡəˈrɛnək/; Somali: garanuug; Litocranius walleri), also known as the giraffe gazelle, is a long-necked antelope found in the Horn of Africa and the drier parts of East Africa. The sole member of the genus Litocranius, the gerenuk was first described by the naturalist Victor Brooke in 1878. It is characterised by its long, slender neck and limbs. The antelope is 80–105 centimetres (31–41 in) tall, and weighs between 28 and 52 kilograms (62 and 115 lb). Two types of colouration are clearly visible on the smooth 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 centimetres (9.8–17.3 in).

    The generuk according to MammalMAP
    provided by EOL authors

    Also known as the Waller's gazelle, the gerenuk (Litocranius walleri), call the dry shrubland of East Africa home. The Somalian word ’Gerenuk’ means ‘Giraffe-necked’ – and it’s easy to see how these antelopes earned this name! Their long necks allow them to reach branches 6-8 ft. off the ground. They extend this reach even further by standing upright on their hind legs while feeding. The Gerenuk once had a wide distribution in Africa, but are currently thought to occur only in southern Djibouti, Somalia, Ethiopia, Kenya and North-eastern Tanzania. For more info visit the MammalMAP virtual museum or blog.

Comprehensive Description

    Gerenuk
    provided by wikipedia

    The gerenuk (/ˈɡɛrɪnʊk, ɡəˈrɛnək/; Somali: garanuug; Litocranius walleri), also known as the giraffe gazelle, is a long-necked antelope found in the Horn of Africa and the drier parts of East Africa. The sole member of the genus Litocranius, the gerenuk was first described by the naturalist Victor Brooke in 1878. It is characterised by its long, slender neck and limbs. The antelope is 80–105 centimetres (31–41 in) tall, and weighs between 28 and 52 kilograms (62 and 115 lb). Two types of colouration are clearly visible on the smooth 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 centimetres (9.8–17.3 in).

    Taxonomy

    .mw-parser-output table.clade{border-spacing:0;margin:0;font-size:100%;line-height:100%;border-collapse:separate;width:auto}.mw-parser-output table.clade table.clade{width:100%}.mw-parser-output table.clade td{border:0;padding:0;vertical-align:middle;text-align:center}.mw-parser-output table.clade td.clade-label{width:0.8em;border:0;padding:0 0.2em;vertical-align:bottom;text-align:center}.mw-parser-output table.clade td.clade-slabel{border:0;padding:0 0.2em;vertical-align:top;text-align:center}.mw-parser-output table.clade td.clade-bar{vertical-align:middle;text-align:left;padding:0 0.5em}.mw-parser-output table.clade td.clade-leaf{border:0;padding:0;text-align:left;vertical-align:middle}.mw-parser-output table.clade td.clade-leafR{border:0;padding:0;text-align:right}              

    Gazella

       

    Blackbuck

           

    Eudorcas

       

    Nanger

             

    Gerenuk

       

    Springbok

           

    Saiga

         

    Oribi

          Phylogenetic relationships of the gerenuk (Bärmann et.al. 2013)

    The scientific name of the gerenuk is Litocranius walleri. The gerenuk is the sole member of the genus Litocranius, and is placed in the family Bovidae. The species was first described by Anglo-Irish naturalist Victor Brooke in 1878.[2] In 1997, Colin Groves proposed that Litocranius is a sister taxon of Ammodorcas, but withdrew from this in 2000.[2] The vernacular name "gerenuk" comes from the Somali word gáránúug , meaning "giraffe-necked".[3] It is also known as the "giraffe gazelle" due to its resemblance to the giraffe.[4]

    In 1999, a phylogenetic study based on cytochrome b and cytochrome c oxidase subunit III analysis showed that the tribe Antilopini, to which the gerenuk belongs, is monophyletic.[5] In 2013, Eva Verena Bärmann (of the University of Cambridge) and colleagues revised the phylogeny of Antilopini on the basis of nuclear and mitochondrial data. The cladogram prepared by them showed that the springbok (Antidorcas marsupialis) forms a clade with the gerenuk; this clade is sister to the saiga (Saiga tatarica, tribe Saigini) and the genera Antilope (blackbuck), Eudorcas, Gazella and Nanger (of Antilopini).[6]

    Two subspecies are identified,[2][7] which are sometimes considered to be independent species:[8][9]

    Description

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

    The gerenuk is a notably tall, slender antelope that resembles gazelles. It is characterised by its long, slender neck and limbs, the flat, wedge-like head and the large, round eyes. Males are nearly 89–105 centimetres (35–41 in) tall, and the shorter females 80–100 centimetres (31–39 in); the head-and-body length is typically between 140 and 160 centimetres (55 and 63 in). Males weigh between 31 and 52 kilograms (68 and 115 lb); females are lighter, weighing 28–45 kilograms (62–99 lb). The species is sexually dimorphic. The tail, that ends in a black tuft, measures 25–35 centimetres (9.8–13.8 in).[8][10]

    Two types of colouration are clearly visible on the smooth coat: the reddish brown 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 centimetres (9.8–17.3 in).[8][10]

    The gerenuk resembles the dibatag, with which it is sympatric in eastern and central Somalia and southeastern Ethiopia. Both are brachyodonts and share several facial and cranial features, along with a two-tone colouration of the coat and strong thick horns (only in males).[11] 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.[8] 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.[11] The subspecies of the gerenuk are similar in colouration; the southern gerenuk is the smaller of the two.[8]

    Ecology and behaviour

    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.[12] 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.[8]

    Fighting and travel are uncommon, possibly as a strategy to save energy for foraging.[4] Both sexes maintain home ranges 3–6 square kilometres (1.2–2.3 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.[9]

    Diet

     src=
    Gerenuks feeding

    Primarily a browser, the gerenuk feed on foliage of bushes as well as trees, shoots, herbs, flowers and fruits. [13] 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 metres (6.6 ft) above the ground.[9] Acacia species are eaten whenever available,[9] while evergreen vegetation forms the diet during droughts.[10] The pointed mouth assists in extracting leaves from thorny vegetation.[9] The gerenuk does not drink water regularly.[13] Major predators of the antelope include Cape hunting dogs, cheetahs, hyenas, lions and leopards.[8]

    Reproduction

    Gerenuk reproduce throughout the year. Females reach sexual maturity at around one year, and males reach sexual maturity at 1.5 years, although in the wild they may only be successful after acquiring a territory (perhaps 3.5 years).[13] The gestation period is about seven months. They are born one at a time, weighing about 3 kg (6.6 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.[14] Gerenuk can live thirteen years or more in captivity, and at least eight years in the wild.[13]

    References

    1. ^ IUCN SSC Antelope Specialist Group (2008). "Litocranius walleri". IUCN Red List of Threatened Species. Version 2012.1. International Union for Conservation of Nature. Retrieved 21 June 2012..mw-parser-output cite.citation{font-style:inherit}.mw-parser-output q{quotes:"""""'"'"}.mw-parser-output code.cs1-code{color:inherit;background:inherit;border:inherit;padding:inherit}.mw-parser-output .cs1-lock-free a{background:url("//upload.wikimedia.org/wikipedia/commons/thumb/6/65/Lock-green.svg/9px-Lock-green.svg.png")no-repeat;background-position:right .1em center}.mw-parser-output .cs1-lock-limited a,.mw-parser-output .cs1-lock-registration a{background:url("//upload.wikimedia.org/wikipedia/commons/thumb/d/d6/Lock-gray-alt-2.svg/9px-Lock-gray-alt-2.svg.png")no-repeat;background-position:right .1em center}.mw-parser-output .cs1-lock-subscription a{background:url("//upload.wikimedia.org/wikipedia/commons/thumb/a/aa/Lock-red-alt-2.svg/9px-Lock-red-alt-2.svg.png")no-repeat;background-position:right .1em center}.mw-parser-output .cs1-subscription,.mw-parser-output .cs1-registration{color:#555}.mw-parser-output .cs1-subscription span,.mw-parser-output .cs1-registration span{border-bottom:1px dotted;cursor:help}.mw-parser-output .cs1-hidden-error{display:none;font-size:100%}.mw-parser-output .cs1-visible-error{font-size:100%}.mw-parser-output .cs1-subscription,.mw-parser-output .cs1-registration,.mw-parser-output .cs1-format{font-size:95%}.mw-parser-output .cs1-kern-left,.mw-parser-output .cs1-kern-wl-left{padding-left:0.2em}.mw-parser-output .cs1-kern-right,.mw-parser-output .cs1-kern-wl-right{padding-right:0.2em}
    2. ^ a b c d Wilson, D.E.; Reeder, D.M., eds. (2005). Mammal Species of the World: A Taxonomic and Geographic Reference (3rd ed.). Johns Hopkins University Press. p. 682. ISBN 978-0-8018-8221-0. OCLC 62265494.
    3. ^ "Gerenuk". Merriam-Webster Dictionary. Retrieved 15 March 2016.
    4. ^ a b Mares, M.A. (1999). Encyclopedia of Deserts. Norman, Oklahoma (USA): University of Oklahoma Press. pp. 235–6. ISBN 9780806131467.
    5. ^ Rebholz, W.; Harley, E. (1999). "Phylogenetic relationships in the bovid subfamily Antilopinae based on mitochondrial DNA sequences". Molecular Phylogenetics and Evolution. 12 (2): 87–94. doi:10.1006/mpev.1998.0586.
    6. ^ Bärmann, E.V.; Rössner, G.E.; Wörheide, G. (2013). "A revised phylogeny of Antilopini (Bovidae, Artiodactyla) using combined mitochondrial and nuclear genes" (PDF). Molecular Phylogenetics and Evolution. 67 (2): 484–93. doi:10.1016/j.ympev.2013.02.015. PMID 23485920.
    7. ^ Groves, C.; Grubb, P. (2011). Ungulate Taxonomy. Baltimore, Maryland: Johns Hopkins University Press. p. 156. ISBN 9781421400938.
    8. ^ a b c d e f g Castelló, J.R. Bovids of the World: Antelopes, Gazelles, Cattle, Goats, Sheep, and Relatives. Princeton, New Jersey (USA): Princeton University Press. pp. 158–63. ISBN 9780691167176.
    9. ^ a b c d e Kingdon, J. (2015). The Kingdon Field Guide to African Mammals (2nd ed.). London, UK: Bloomsbury. pp. 569–71. ISBN 978-1-4729-1236-7.
    10. ^ a b c Estes, R.D. (2004). The Behavior Guide to African Mammals : Including Hoofed Mammals, Carnivores, Primates (4th ed.). Berkeley, California (USA): University of California Press. pp. 84–90. ISBN 9780520080850.
    11. ^ a b Kingdon, J. (2013). Mammals of Africa. London: Bloomsbury. pp. 387–90. ISBN 9781408122570.
    12. ^ Leuthold, B.M.; Leuthold, W. (1978). "Daytime activity patterns of gerenuk and giraffe in Tsavo National Park, Kenya". African Journal of Ecology. 16 (4): 231–43. doi:10.1111/j.1365-2028.1978.tb00444.x.
    13. ^ a b c d Leuthold, Walter (1978). "Ecology of the gerenuk Litocranius walleri". Journal of Animal Ecology. 47 (2): 561–580. doi:10.2307/3801. JSTOR 3801.
    14. ^ "One of our member institutions working with assisted reproductive techniques". Conservation Centers for Species Survival. Retrieved 3 June 2013.

    Lifespan, longevity, and ageing
    provided by AnAge articles
    Maximum longevity: 17.3 years (captivity) Observations: In the wild, these animals have been estimated to live up to 12 years (Bernhard Grzimek 1990). One captive specimen lived for 17.3 years (Richard Weigl 2005).

Distribution

    Distribution
    provided by Animal Diversity Web

    Litocranius walleri inhabits the dry brushy region of east Africa from the Serengeti plain of Tanzania north along the coast through Kenya, Ethiopia, Eritrea, and into southern Somalia. The species was once found in eastern Egypt and northeastern Sudan as well.

    Biogeographic Regions: ethiopian (Native )

Morphology

    Morphology
    provided by Animal Diversity Web

    The long neck and long, thin legs of gerenuks are their defining features; these make them one of the world's most easily recognized antelopes. The coat is of a short, fine, glossy hair that is evenly distributed over the whole body. The pelage is a pale tawny brown with white along the breast, underbelly, and inner legs. There are small, dark patches of fur on the knees of the forelegs and at the end of the tail. The head is long and narrow with medium-sized ears, and the cheek teeth and masseter muscle are reduced. On the head there is a dark patch around the eyes that pales as it goes outward until it forms a white rim. Only males of this species have head ornamentation in the form of scimitar shaped horns ranging from 25 to 44 centimeters in length. Both sexes of L. walleri are of similar size but the males are more muscular than females causing them to outweigh them. Mass ranges from 29 to 58 kg, total body length from 140 to 160 cm, and tail length from 220 to 350 mm.

    Range mass: 29 to 58 kg.

    Range length: 140 to 160 cm.

    Other Physical Features: endothermic ; homoiothermic; bilateral symmetry

    Sexual Dimorphism: ornamentation

Habitat

    Habitat
    provided by Animal Diversity Web

    The habitat that Litocranius walleri occupies varies from the treeless plains of Tanzania in the southern reaches of its range to the dry high deserts of Kenya. They are adaptable and do well in a variety of habitats, provided there is a good supply of succulent plants.

    Range elevation: 0 to 3,000 m.

    Habitat Regions: tropical ; terrestrial

    Terrestrial Biomes: desert or dune ; savanna or grassland

Trophic Strategy

    Trophic Strategy
    provided by Animal Diversity Web

    Litocranius walleri is well adapted for obtaining forage from their arid habitats. Their long necks, long legs, and the ability to stand on their hind legs allows L. walleri to obtain tree leaves that are out of reach for most other antelope species. This permits gerenuks to be selective in the foods they eat and to be efficient browsers of herbaceous plants. Over 80 different species of plants have been found in a single individuals stomach. L. walleri does not drink free standing water, they instead rely on water taken in when they eat succulent plants.

    Plant Foods: leaves; seeds, grains, and nuts

    Primary Diet: herbivore (Folivore )

Associations

    Associations
    provided by Animal Diversity Web

    Although rare, gerenuk contribute to nutrient cycling in the ecosystems in which they live through their foraging activity. They also act as prey species for large predators.

    Associations
    provided by Animal Diversity Web

    Several anti-predator adaptations have evolved in Litocranius walleri for their survival both while they are juveniles and as adults. Young L. walleri remain motionless while hiding in the bushes and tall grasses not far from their mothers during the day when the mother is feeding. As adults they show an adaptation that is more common to forest dwelling antelopes than to desert-adapted ones, they freeze at the aproach of danger. They are preyed on by a diverse set of large predators found throughout their range.

    Known Predators:

    • cheetahs (Acinonyx jubatus)
    • leopards (Panthera pardus)
    • lions (Panthera leo)
    • cape hunting dogs (Lycaon pictus)
    • hyenas (Hyaenidae)
    • servals (Leptailurus serval)
    • ratel (Mellivora capensis)
    • caracals (Caracal caracal)
    • large eagles (Accipitridae)

Behavior

    Behavior
    provided by Animal Diversity Web

    Communication Channels: visual ; tactile ; acoustic ; chemical

    Other Communication Modes: pheromones ; scent marks

    Perception Channels: visual ; tactile ; acoustic ; chemical

Life Expectancy

    Life Expectancy
    provided by Animal Diversity Web

    The average life span of female Litocranius walleri is slightly longer than males. Their lifespan in the wild averages 10 - 12 years.

    Typical lifespan
    Status: wild:
    10 to 12 years.

    Average lifespan
    Status: captivity:
    13.0 years.

Reproduction

    Reproduction
    provided by Animal Diversity Web

    The mating ritual of Litocranius walleri is complex. When a male encounters a potential mate the female will raise her nose into the air and pull her ears close to the head as a sign of defensiveness, meanwhile the male displays his horns and neck in a sideways pose. If the female is receptive then the male will mark the female on the thigh with the contents of his preorbital gland and contiue to follow her around, a form of mate guarding. As the male follows the female he continually uses his forelegs to kick the female in her thigh region. When the female atempts to urinate the male performs the flehmen test or lip curl test in which he samples her urine. Once the female comes into estrous the male will notice the difference in the females urine and mating will begin. Males will attempt to mate with as many females as they can. (Macdonald, 1984)

    Mating System: polygynous

    Gerenuk females breed every one to two years, depending on the sex of their previous year's offspring. Males are dependent on their mothers for longer than are females. Reproduction and births occur throughout the year and may depend on the quality of available nutrition. Females give birth to usually one young after a gestation period of about 165 days.

    Breeding season: Breeding occurs throughout the year.

    Range number of offspring: 1 (low) .

    Average number of offspring: 1.

    Range gestation period: 6.77 to 7 months.

    Range weaning age: 12 to 18 months.

    Range age at sexual or reproductive maturity (female): 1 to 2 years.

    Range age at sexual or reproductive maturity (male): 1 to 2 years.

    Key Reproductive Features: iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; fertilization (Internal ); viviparous

    Average number of offspring: 1.

    Female Litocranius walleri usually give birth to one young, rarely two. The young are precocial and begin to walk within minutes of birth. The female continues to look after her young until she weans them. Young females get weaned when they reach one year of age but male offspring are not weaned until they reach at least one and a half years old and stay with their mothers until after they are two.

    Parental Investment: altricial ; female parental care ; post-independence association with parents

Conservation Status

    Conservation Status
    provided by Animal Diversity Web

    Litocranius walleri is a game animal, even though its not very common, and as a game animal it is protected in most of its range in the form of tags or permits. There are many parks offering sanctuary for them within their range and many biologists and game managers studying them so they are not considered to be at significant risk currently.

    US Federal List: no special status

    CITES: no special status

    IUCN Red List of Threatened Species: near threatened

Benefits

    Benefits
    provided by Animal Diversity Web

    There are no adverse effects of L. walleri on humans.

    Benefits
    provided by Animal Diversity Web

    Litocranius walleri has been a game animal in Africa for over 200 years. Although they are limited in supply for hunters and have a limited range, they continue to be hunted for trophies and for bush meat. In the expanding world of photosafaries and parks in Africa L. walleri will become a regular subject for this endeavor. Unfortunately L. walleri doesn't do well in captivity and has rarely been bred in zoos.

    Positive Impacts: food ; ecotourism