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Understanding the spatial dynamics of landscape use by free-ranging herbivores is essential for species management and conservation in its natural environment. We used Ivelv's selection index, binary logistic regression analyses and stepwise regression to understand how environmental factors shape habitat selection by the Grevy's zebra (Equus greyvi). We measured biotic, abiotic and human factors that may influence presence or absence of Grevy's zebra in Samburu-Laikipia landscape and showed: (1) during wet periods, percentage perennial grasses, livestock density and grass quality had the greatest effect on Grevy's zebra presence; but (2) during dry weather periods a different suite of factors determined their landscape distribution, namely, the percentage of tree and bush density, distance to water and overall grass abundance. In addition, different Grevy's zebra demographic and reproductive classes varied in their response to environmental selective forces, thus demonstrating flexibility in their pat-terns of habitat selection. While we recommend more detailed studies on how abiotic and biotic interact to shape habitat selection patterns, our findings underscored the need of maintaining both dry and wet season habitats to ensure essential grazing area refugia. Our findings show that 'soft' development with controlled livestock stocking rates within the landscape will enhance Grevy's zebra conservation. [ABSTRACT FROM AUTHOR]

A 22-year and 9-month-old female Grevy's zebra (Equus grevyi) showed signs of polyuria, polydipsia, glucosuria, and muscle atrophy. Blood tests revealed hyperglycemia, hypertriglyceridemia, electrolyte imbalance, high levels of adrenocorticotropic hormone (ACTH) and cortisol, and low levels of hormones secreted by the pituitary pars distalis. Pathological examinations revealed a pituitary gland tumor and bilateral adrenal cortical hyperplasia. Pituitary tumor cells showed immunoreactivity for α-melanocyte-stimulating hormone and ACTH. The deposition of amyloid β was observed in the parenchyma and vascular walls of the cerebrum. The zebra showed clinical signs of pituitary pars intermedia dysfunction and was histopathologically diagnosed with pituitary gland melanotroph adenoma. This case report provides insight into neoplastic and endocrine diseases associated with the aging of a zebra. [ABSTRACT FROM AUTHOR]

Since the 1970s, the globally endangered Grevy's zebra Equus grevyi has suffered a substantial reduction in range and population size. Grevy's zebra was introduced into the Tsavo ecosystem in two translocations: 22 individuals released in Tsavo East National Park in 1964 and 30 individuals released in Tsavo West National Park in 1977. This study focuses on the Tsavo East subpopulation within the Kasigau Corridor REDD+ Project Area. Data were collected from 2011 to 2014 using systematic and ad lib methods, while vegetation stratification was based on tonnes of CO2e per hectare. Cumulatively, 785 Grevy's zebra were seen in 210 encounters. The largest single group comprised of 24 individuals; mean group size was 4 ± 3. Foals comprised 10% of all individuals seen and were recorded across most months, suggesting year-round breeding. The range core for the Grevy's zebra in this area was estimated to be 400 km2. Its density was estimated at 0.09 ± 0.038 individuals per km2, translating to a population of 36 ± 15 individuals (range: 6-67) based on the estimated core range. Grasslands and sparse Acacia- Commiphora vegetation strata were used significantly more than expected. Despite constituting only about 2-3% of the global Grevy's zebra population, this subpopulation could still play a role as a - disconnected - reserve population. [ABSTRACT FROM AUTHOR]

Although nursing non-filial offspring (allonursing) represents costly behaviour to the female, it occurs in a variety of taxa, including ungulates. The only three currently existing species of zebra differ in their ecology and social system. In the wild, mountain zebra Equus zebra and Grevy's zebra Equus grevyi live in arid environments, while plains zebra Equus quagga inhabit savannahs. Mountain and plains zebra mares form long-term stable herds associated with a social hierarchy, whereas Grevy's zebra mares form loose associations of short duration. In this study, we investigated the occurrence of allosuckling in three zebra species at the Dvůr Králové Zoo, Czech Republic, during 1626 h of observation. We recorded no successful allosuckling bouts and only 1 and 22 attempts to allosuckle by foals of mountain and plains zebra, respectively, whereas we observed 117 attempts and 13 successful allosuckling bouts by Grevy's zebra foals. Moreover, more than half of all observed Grevy's zebra foals succeeded in allosuckling at least once. When rejecting an allosuckling attempt, Grevy's zebra mares were less aggressive than mountain and plains zebra mares. When a Grevy's zebra mare allowed occasional allosuckling by a non-filial foal, the probability of long-term allosuckling was smaller than that in mountain and plains zebra. We also present the first evidence of adoption in Grevy's zebra. We suggest that higher tolerance towards non-filial offspring, including the occurrence of allosuckling in Grevy's zebra, was affected by the different social systems of zebra species. [ABSTRACT FROM AUTHOR]

This paper describes the postpartum behavior of a wild Grevy's zebra ( Equus grevyi) mare and foal. The foal first attempted to stand within 5 min of birth and succeeded at approximately 10 min after birth. Within 40 min of birth, the infant could walk steadily. The foal did not suckle during the observation time. An ethogram of observed behaviors is provided. [ABSTRACT FROM AUTHOR]

Hybridization between an abundant species and an endangered species is cause for concern. When such hybridization is observed, it is both urgent and necessary to assess the level of threat posed to the endangered species. We report the first evidence of natural hybridization between two equids: the endangered Grevy's zebra Equus grevyi and the abundant plains zebra Equus burchelli. Grevy's zebra now number <3000 individuals globally, and occur only in northern Kenya and Ethiopia. In recent years, Grevy's zebra have become increasingly concentrated in the south of their range due to habitat loss in the north. Both species are sympatric in the Laikipia ecosystem of northern Kenya, where we have observed purportedly hybrid individuals. Using mitochondrial and Y chromosome DNA, we confirmed the hybrid status of the morphologically identified hybrids and demonstrate conclusively that all first-generation hybrids are the offspring of plains zebra females and Grevy's zebra males. Behaviorally, hybrids integrate themselves into plains zebra society, rather than adopting the social organization of Grevy's zebra. Two hybrids have successfully raised foals to over 3 months in age, including one which has reached adulthood, indicating the fertility of female hybrids and viability of their offspring. We hypothesize that hybridization occurs due to (1) skewed sex ratios, in favor of males, within Grevy's zebra and (2) the numerical dominance of plains zebra in the region where hybridization is occurring. Stakeholders have discussed hybridization as a potential threat to Grevy's zebra survival. We argue, however, based on behavioral observations, that hybridization is unlikely to dilute the Grevy's zebra gene pool in the short term. As a conservation concern, hybridization is secondary to more direct causes of Grevy's zebra declines. [ABSTRACT FROM AUTHOR]

An anthrax outbreak occurred in the Wamba area of southern Samburu, Kenya, between December 2005 and March 2006. The outbreak affected equids including the endangered Grevy's zebras ( Equus grevyi), plain zebras ( Equis Burchelli) and donkeys ( Equus asinus). Most of the deaths were localized in Nkaroni area just west of Wamba town. The diagnosis of anthrax was rapidly confirmed by bacteriological methods. The relevant government departments, including the Kenya Wildlife Service and Veterinary Department, and other stakeholders were promptly informed. Fifty-three Grevy's zebra and 26 plains zebras died from anthrax. An equal number (eighteen) of adult male and female Grevy's zebras succumbed to the disease. The outbreak affected immature and mature individuals equally. The dead plain zebras included fifteen adult females, two adult males and nine immature individuals. The Veterinary Department responded by vaccinating livestock while Kenya Wildlife Service vaccinated 620 Grevy's zebras within southern Samburu. Examination of sites at which carcasses of animals which succumbed to the disease were burnt, revealed that unsupervised burning did not eliminate anthrax spores in 42% of the cases (n = 14). There is an urgent need to incorporate strategic wildlife disease monitoring in the struggle to save Grevy's zebras and other endangered species. [ABSTRACT FROM AUTHOR]

Objective--To determine ECG and echocardiographic measurements in healthy anesthetized Grevy's zebras (Equus grevyl). Animals--20 healthy zebras. Procedures--Auscultation, base-apex ECG, and echocardiography were performed on anesthetized zebras. Results--Low-grade systolic murmurs were detected in the left basilar region in 4 of 20 zebras. Evaluation of ECGs from 19 zebras revealed sinus rhythm with a predominantly negative QRS complex and a mean ± SD heart rate of 67 ± 10 beats/min. Echocardiograms of sufficient image quality were obtained for 16 zebras. Interventricular septal thickness in diastole, left ventricular chamber in diastole and systole, left atrial diameter, and left ventricular mass were significantly and moderately correlated with estimated body weight (r values ranged from 0.650 to 0.884). Detectable swirling of blood in the right and sometimes the left ventricles was detected in 9 of 16 zebras, whereas physiologic regurgitation of blood was detected for the aortic valve in 3 zebras, pulmonary valve in 2 zebras, mitral valve in 2 zebras, and tricuspid valve in 1 zebra. Conclusions and Clinical Relevance--Results of this study provide reference information for use in the cardiac evaluation of anesthetized Grevy's zebras. [ABSTRACT FROM AUTHOR]

The article discusses hybridization between Grevy's zebra and plains zebras and how understanding this process can be useful for conservation management purposes. According to the author, determining this issue is vital to the conservation of the Grévy's zebra which is already an endangered equid species. One important move is monitoring the prevalence of hybridization and the fitness of hybrids and their backcrosses. In addition, assessment of historic aspects of gene flow between the species may be useful in evaluating nuclear autosomal markers.