Gerenuk Research Articles

Population size and structure of beisa oryx and gerenuk in Geralle National Park, southeastern Ethiopia.

The study was conducted to determine the population size of endangered Oryx beisa (Rüppell, 1835), and near-threatened Litocranius walleri (Brooke, 1878) of uncertain global population estimates in Geralle National Park, southeastern Ethiopia. Systematic line transects were established with a transect length range of 2.3 to 6.8 km long (a total of 165.4 km long with a sighting distance of 150 m after truncation). The combination of AIC and chi-square p-values was used as model selection criteria for density/population size estimation in distance sampling software. The lowest AIC, ∆AIC (close to zero), and Chi-square tests (p-value > .05) were selected with adequate model fit. The minimum observation was 67 individuals of beisa oryx in the dry season. The maximum observation was 349 individuals of gerenuk during the wet season. The minimum detection probability of oryx was in the wet season (p â = 76 ± 26), and the minimum detection probability of gerenuk was (p â = 75 ± 1) in both seasons. The two-season pooled density analyzed for studied species indicated (0.85 ± 0.34, 1.24 ± 0.47, beisa oryx/km2), and (3.82 ± 0.6, 4.88 ± 0.7 gerenuk/km2) in dry and wet seasons, respectively. It can be concluded from the results of the study that GNP is home to previously undiscovered healthy populations of the endangered beisa oryx and near-threatened gerenuk. So it is recommended to undergo in-depth population studies, including other species available in the national park and their habitat components, so as to design sound, sustainable conservation measures for the wildlife resources in the area.

Are Madagascar's obligate grazing-lawns ancient and evolved with endemic herbivores, or recently selected by introduced cattle?

Are Madagascar's obligate grazing-lawns ancient and evolved with endemic herbivores, or recently selected by introduced cattle?

Functional Modularization in the Neck Muscles of the Gerenuk (Litocranius walleri)

The gerenuk (Litocranius walleri) is an African ruminant that feeds on high growing foliage by standing erect on its hindlimbs and extending its long neck. We hypothesize that extensive myological adaptation would be present in the muscles that facilitate head stability and movement, as well as muscles that anchor the neck. The vertebral musculature from the atlas to the thoracic vertebrae of a gerenuk specimen was dissected and compared to that of other ruminants. Several muscles were found to have narrowed or shifted caudally along the vertebral column, resulting in their cranial‐most attachment point being the fifth cervical vertebrae (C5). Similarly, two muscles were found to have shifted cranially, resulting in their caudal‐most attachment point also being C5. Caudally shifted muscles include m. serratus ventralis cervicis, the scalene muscles, m. rhomboideus cervicis, and the cervical part of the trapezius. Cranially shifted muscles include m. splenius cervicis and m. longissimus capitis. These shifts indicate a significant degree of modularization occurring between head movement muscles and neck stability muscles, with C5 being the boundary. Further adaptation that was not part of modularization around C5 was found in the segmental muscles attaching between vertebral processes. Segments of m. intertransversarii and m. multifidi have elongated and undergone specialization at the cranial attachments. The segments of m. spinalis cervicis were found to have a complex configuration that interdigitates with the multifidi. Additionally, m. levator claviculae and m. iliocostalis cervicis were present, neither of which have been previously described in ruminants. Previously published work reported that osteological adaptation in the gerenuk neck is especially pronounced in C1 – C4, which is consistent with our findings of myological modularization occurring with C5 as the boundary.

Diversity and habitat association of medium and large mammals in Gibe Sheleko National Park, Southern Ethiopia.

Complete documentation on the status of mammals is indispensable for appropriate conservation measures in protected areas. However, there is inadequate information on mammalian resources in the ecosystem of Gibe Sheleko National Park (GSNP). Thus, the study aimed to assess species diversity, abundance, and habitat association of medium‐ and large‐sized mammals in GSNP. We stratified the study area into five dominant habitat types, namely dense forest, wooded grassland, grassland, riverine forest, and farmland habitat types based on land cover and vegetation structures and further employed stratified random sampling technique across each habitat type. The sample transects covered 20% of the study area. Transect width ranged from 50 m to 400 m based on vegetation cover and visibility of mammals. The main data were collected via direct observation. Data were analyzed via chi‐square test and species diversity indexes. We recorded the total of 20 mammals species' those belong to 10 families of which 8 species were large‐sized and 12 species medium‐sized mammals. There were two IUCN vulnerable species, namely Hippopotamus amphibious and Panthera pardus, and two globally near‐threatened species, particularly Litocranius walleri and Caracal caracal in the study area. Dense forest held the highest species diversity of medium‐ and large‐sized mammals (H′ = 2.28) with the highest evenness index (J = 0.84). Riverine forest had the least diversity with uneven population distribution. Papio anubis was the most abundance species, whereas Caracal caracal was the least abundant in the study area. GSNP is home for threatened and spectacular mammals species'; hence, an appropriate conservation measure is mandatory to keep existing mammals species'.

EVALUATION OF A VISUAL ENZYME-LINKED IMMUNOSORBENT ASSAY (ELISA) FOR PREGNANCY DETECTION IN FOUR UNGULATE SPECIES.

This study evaluated the use of a commercially available, visual enzyme-linked immunosorbent assay (ELISA) for diagnosis of pregnancy in okapi (Okapia johnstoni), gerenuk (Litocranius walleri), eastern giant eland (Tragelaphus derbianus spp. gigas), and dama gazelle (Nanger dama). This assay has been validated for use in domestic cattle, sheep, goats, and water buffalo. Unlike other blood-based pregnancy associated glycoprotein (PAG) detection methods, this assay does not require sophisticated laboratory equipment for detection or interpretation and can therefore be utilized in many settings. Banked serum samples from gerenuk (n = 11), giant eland (n = 4), dama gazelle (n = 33) and okapi (n = 3) were tested, and a pregnant and nonpregnant sample from each individual were included. The ELISA showed 100% sensitivity and specificity in gerenuk and giant eland samples, and 0% sensitivity in dama gazelle and okapi samples. Using this assay, pregnancy was detected by 7-8 wk gestation in gerenuk and 6 wk in giant eland. These results are consistent with previous studies that were able to accurately detect pregnancy in other members of the family Bovidae, but it is possible that PAGs present in okapi and dama gazelle are structurally dissimilar relative to the intended test target, and are therefore unrecognizable using this test. The faint positivity in the dama gazelle assays may be due to cross-reactivity with other proteins in the sample, or due to inconsistent binding with the dama gazelle PAG. This ELISA appears to be an accurate, rapid, and inexpensive method of point-of-care pregnancy diagnosis in gerenuk and giant eland, but not okapi and dama gazelle. Additional studies should be pursued to further characterize the limits of pregnancy detection using this assay in gerenuk and giant eland, and to investigate the validity of this test in other nondomestic ruminant species.

Digesta passage in nondomestic ruminants: Separation mechanisms in ‘moose-type’ and ‘cattle-type’ species, and seemingly atypical browsers

Ruminants have been classified as having a ‘moose-type’ or ‘cattle-type’ digestive physiology. ‘Cattle-type’ ruminants have a clear difference in the mean retention time (MRT) of fluid vs. small particles in the reticulorumen (RR), with a high ‘selectivity factor’ (SF = MRTparticle/ MRTfluid, >1.80), and are typically grazers and intermediate feeders. ‘Moose-type’ ruminants have lower SF (<1.80), possibly because of defensive salivary proteins that constrain amounts of (high-viscosity) saliva, and are typically restricted to browsing. To further contribute to testing this physiology-diet correlation, we performed 55 individual passage measurements in 4/6 species that have/have not been investigated previously, respectively. Co-EDTA was used as a solute (fluid) and Cr-mordanted hay particles (<2 mm) as particle markers. Results are related to the percentage of grass in the natural diet taken from the literature. Moose (Alces alces, n = 4 on 4 to 5 diets each and n = 2 on a single diet, 5% grass, SF 1.46 ± 0.22) and giraffe (Giraffa camelopardalis, n = 3 on 3 to 5 diets each, 1%, 1.42 ± 0.23) as classical ‘moose-type’, and cattle (Bos taurus, n = 2, 70%, 2.04) as classical ‘cattle-type’ ruminants yielded results similar to those previously published, as did waterbuck (Kobus ellipsiprymnus, n = 5, 84%, 2.46 ± 0.49), corroborating that the SF represents, to a large extent, a species-specific characteristic. Results in oryx (Oryx leucoryx, n = 1, 75%, 2.60) and sitatunga (Tragelaphus spekii, n = 4, 68%, 1.81 ± 0.21) correspond to the concept of ‘cattle-type’ ruminants being grazers or intermediate feeders. However, European bison (Bison bonasus, n = 1, 10%, 2.74), nyala (T. angasii, n = 6, 20%, 1.95 ± 0.25), bongo (T. eurycerus, n = 3, 13%, 2.39 ± 0.54) and gerenuk (Litocranius walleri, n = 1, 0%, 2.25) appear as ‘cattle-type’ ruminants, yet have a browse-dominated diet. While the results do not challenge the view that a ‘moose-type’ digestive physiology is an adaptation to browse diets, they indicate that it may not be the only adaptation that enables ruminants to use browse. Apparently, a ‘cattle-type’ digestive physiology with a high SF does not necessarily preclude a browsing diet niche. High-SF browsers might have the benefit of an increased harvest of RR microbiota and grit removal prior to rumination; how they defend themselves against secondary plant compounds in browse remains to be investigated.

Growth Pattern and Functional Morphology of the Cervical Vertebrae in the Gerenuk (Litocranius walleri): The Evolution of Neck Elongation in Antilopini (Bovidae, Artiodactyla)

Long necks have evolved independently in several different taxa, but the processes underlying the evolution of this trait are not yet fully understood. In this study, we examined the skeletal mechanism underlying the neck elongation in the tribe Antilopini (Bovidae, Artiodactyla). We calculated the growth patterns of the cervical vertebrae in the gerenuk (Litocranius walleri), which possesses the longest neck in this tribe, and compared it with those in two related species. The growth rates of the vertebrae were not significantly different between species, suggesting that the long neck of the gerenuk has resulted from the elongation of the cervical vertebrae during the fetal or juvenile stage. The morphology of the cervical vertebrae of gerenuks differed from that of the closely related, relatively long-necked dama gazelle (Nanger dama), with protrusions occurring on the dorsal surface of the ventral arch of the atlas. This implies that gerenuks possess a well-developed transverse ligament of the atlas that functions to hold the dens of the axis against the atlas. We also found that the atlas lies in close proximity to the neural spine of the axis in the gerenuk, suggesting that hyperextension of the atlantoaxial joint is osteologically limited in this species. While foraging on high foliage, gerenuks flex and extend their necks freely in a bipedal posture without moving their entire body. These morphological characteristics peculiar to the gerenuk enhance the rigidity of the atlantoaxial joint and decrease the risk of subluxation of the joint during this unique foraging behavior.

Osteofluorosis in Captive Gerenuk (Litocranius walleri) and Bongo (Tragelaphus eurycerus isaaci) Antelope

Multiple cases of lameness in gerenuk (Litocranius walleri) and bongo antelope (Tragelaphus eurycerus isaaci) associated with high levels of fluoride in a commercial feed are reported. Clinical pathology and histopathology findings are described and the response to treatment is documented. The case highlights the importance of quality control in feed management.

CONTAGIOUS CAPRINE PLEUROPNEUMONIA OUTBREAK IN CAPTIVE WILD UNGULATES AT AL WABRA WILDLIFE PRESERVATION, STATE OF QATAR

Contagious caprine pleuropneumonia (CCPP) caused by Mycoplasma capricolum subsp. capripneumoniae is a highly contagious and serious respiratory disease of domestic goats, characterized by coughing, severe respiratory distress, and high mortality rates. The lesions at necropsy are mainly a fibrinous pleuropneumonia with increased straw-colored pleural fluid. An outbreak of CCPP in wild goat (Capra aegagrus), Nubian ibex (Capra ibex nubiana), Laristan mouflon (Ovis orientalis laristanica), and gerenuk (Litocranius walleri) occurred at Al Wabra Wildlife Preservation in the State of Qatar. The disease was suspected because of the clinical symptoms and the necropsy findings and was confirmed by the isolation and identification of the causative organism. This new finding indicates that CCPP should be considered a potential threat to wildlife and the conservation of endangered ruminant species, especially in the Middle East, where it is enzootic because of its presence in chronic carriers. Susceptible imported animals should be quarantined and vaccinated. The preferred samples for diagnosis are the pleural fluid, which contains high numbers of Mycoplasma, and sections of hepatized lung, preferably at the interface of normal and diseased tissues. Samples must be shipped to diagnostic laboratories rapidly, and appropriate cool conditions must be maintained during shipping.

Types, type locality and subspecies of the gerenuk Litocranius walleri (Artiodactyla: Bovidae)

AbstractFrom what is known about the discovery of the gerenuk Litocranius walleri, the type locality is here restricted to the vicinity of Chisimaio, Somalia. Two discrete subspecies can be recognized. The smaller L. w. walleri occurs in north‐east Tanzania, Kenya, southern Somalia and southern Ethiopia. The larger L. w. sclateri is restricted to Djibouti, northern Somalia and adjacent parts of northern Ethiopia and is present in very few protected areas.

Captive management of the Gerenuk Litocranius walleri at the St Louis Zoo

Captive management of the Gerenuk <i>Litocranius walleri</i> at the St Louis Zoo

Captive management of the Gerenuk Litocranius walleri at the St Louis Zoo

Captive management of the Gerenuk Litocranius walleri at the St Louis Zoo