The Experts below are selected from a list of 3651 Experts worldwide ranked by ideXlab platform
Laurie Marker - One of the best experts on this subject based on the ideXlab platform.
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conservation genetics of the Cheetah genetic history and implications for conservation
Cheetahs: Biology and Conservation: Biodiversity of the World: Conservation From Genes to Landscapes, 2018Co-Authors: Anne Schmidtkuntzel, Warren E. Johnson, Laurie Marker, Ezequiel Fabiano, Desire L Dalton, Marilyn Menottiraymond, Pauline Charruau, Simone Sommer, Antoinette Kotze, Stephen J ObrienAbstract:Abstract From allozymes in 1983 to whole genomes in 2015, genetic studies of the Cheetah have been extensive. In this chapter we provide an overview of the available literature. Overall, patterns of genetic variation provided evidence of low variability and suggest this loss occurred thousands of years ago. Differences between published subspecies were supported genetically. At a local scale, populations were generally considered panmictic with minor genetic structure. Although Cheetahs have persisted despite low genetic variability, important questions arise from these findings: Does the Cheetah have the ability to adapt to and evolve with future changes in environmental and infectious pressure? How would Cheetahs cope with further loss of genetic diversity? Connectivity in the wild should be maintained via prevention of habitat loss, while management of small isolated populations may require reestablishing gene flow. Genetics could assist captive-breeding decisions and provide forensic evidence as to the geographical origin of illegally traded animals.
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use of livestock guarding dogs to reduce human Cheetah conflict
2018Co-Authors: Amy Dickman, Jane Horgan, Rebecca C Klein, Gail C Potgieter, Kelly J Stoner, Jeannine Mcmanus, Laurie MarkerAbstract:Mitigating conflict between livestock farmers and Cheetahs is key to conserving the species. Livestock guarding dogs (LGDs) have been used to reduce livestock losses to carnivores around the world. In Africa, Cheetah conservation organizations have introduced purebred Anatolian Shepherds, encouraged the use of local dogs, and have experimented with crossbreeding local with purebred dogs. The resulting research has provided insights into how LGDs work under African conditions, guarding their livestock against the large carnivore guild. In this chapter, we examine the effectiveness of LGDs, both in terms of reducing livestock losses in a cost-effective manner and preventing retaliatory killing of Cheetahs and other carnivores. Furthermore, we discuss the various factors contributing to LGD effectiveness, for example, behavioral training, working conditions, and breeding. Finally, we examine the future of LGDs as a means for human-Cheetah conflict mitigation.
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continued decline in genetic diversity among wild Cheetahs acinonyx jubatus without further loss of semen quality
Biological Conservation, 2016Co-Authors: Laurie Marker, Stephen J Obrien, David E Wildt, Kimberly A Terrell, Adrienne E Crosier, Nicola M Anthony, Warren E. JohnsonAbstract:As a well-studied felid with limited genetic diversity, the Cheetah (Acinonyx jubatus) has shaped much of the scientific debate surrounding inbreeding depression. The species survived a population bottleneck ~ 12,000 years ago and was extirpated from > 75% of its historical range in the last century. Modern Cheetahs produce poor-quality semen, a presumed manifestation of inbreeding depression. Within Felidae, a positive association between genetic diversity and semen quality is well supported by pedigree data and inter-species comparisons. However, this relationship has never been examined among individual Cheetahs. Furthermore, whether ongoing population declines are exacerbating inbreeding depression in wild or captive Cheetah populations is unknown. Using 12 microsatellite markers, we evaluated the relationship between heterozygosity and reproductive traits among wild (n = 54) and captive (n = 43) male Cheetahs born from 1976–2007. We tested the hypotheses that genetic diversity has declined over the last ~ 30 years and is positively correlated with semen quality/breeding success in the Cheetah. Findings revealed that genetic diversity has decreased in the wild, but not captive, population. Unexpectedly, heterozygosity was lower in proven versus unproven breeders and did not correlate with semen quality. A small proportion of all males (< 10%) produced relatively high quality ejaculates, with sperm traits similar to those of non-inbred felid species. These data suggest a more complex relationship between inbreeding and male Cheetah reproductive traits than previously appreciated. Intensive management of captive Cheetahs appears to be minimizing inbreeding, whereas the continued erosion of genetic diversity in wild males is of conservation concern.
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spatial and temporal habitat use by gps collared male Cheetahs in modified bushland habitat
Open Journal of Forestry, 2016Co-Authors: Matti T Nghikembua, Jacob Harris, Tom Tregenza, Laurie MarkerAbstract:Cheetahs and other apex predators are threatened by human-wildlife conflict and habitat degradation. Bush encroachment creates one of the biggest forms of habitat change, thus it is important to understand the impact this has on habitat use. We investigated habitat preferences of five male Cheetahs in Namibian farmlands degraded by bush encroachment. Cheetahs were tracked using satellite based Global System for Mobile (GSM) collars providing a higher resolution on ranging behavior. We aimed to investigate: 1) habitat characteristics; 2) evidence for habitat selection; 3) temporal activity partitioning; and 4) whether revisits to locations were related to habitat type. There were differences in habitat characteristics, showing that Cheetahs were able to utilise different habitats. Fecal pellet counts revealed that warthog, oryx, scrub hare and kudu were most abundant. The Cheetahs spent more time in high visibility shrubland, suggesting they selected rewarding patches within predominantly bush-encroached landscapes. The usage in marginal habitat was strikingly influenced by habitat type, with both previously cleared and open vegetated areas showing high proportions in edge use. Individuals exhibited significant temporal activity partitioning, showing peaks between late afternoon and early morning hours. This finding could be key to managing human-wildlife conflict by showing that increased protection such as the use of herders and livestock guarding dogs should be used as mitigation methods to minimize the impact of Cheetah specific temporal patterns at all times as defined in this research. Visits to the same locations were not correlated to habitat type; revisits may be dictated by other reasons such as social interaction, prey density or avoidance of other predators. Findings from this study will help build existing knowledge on the effects bush encroachment has on Cheetah habitat preference.
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feeding ecology of the asiatic Cheetah acinonyx jubatus venaticus in low prey habitats in northeastern iran implications for effective conservation
Journal of Arid Environments, 2012Co-Authors: Mohammad S Farhadinia, Fatemeh Hosseinizavarei, Bagher Nezami, Hadi Harati, Hossein Absalan, Ezequiel Fabiano, Laurie MarkerAbstract:Abstract Feeding ecology of the critically endangered Asiatic Cheetah was investigated from 2004 to 2009 in northeastern Iran where prey population has been depleted due to poaching. The survey was mainly based on scat analysis, complemented by kill monitoring and local inquiries of direct observations. Results of the research revealed that the Asiatic Cheetahs mainly rely on medium-sized ungulates. However, with respect to low density of gazelles, they catch a considerable proportion of their food demands based on livestock which brings the Cheetahs in direct conflict with local people. Meanwhile, smaller mammals only meet a small proportion of Cheetah's diet. Our data indicate high importance of enhancing conservation efforts in northeastern Iran as well as other Cheetah habitats where normal prey ungulates have experienced severe decline.
David W Macdonald - One of the best experts on this subject based on the ideXlab platform.
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spatial ecology of Cheetahs on north central namibian farmlands
Journal of Zoology, 2008Co-Authors: Laurie Marker, Amy Dickman, R M Jeo, M G L Mills, David W MacdonaldAbstract:Knowledge of a species’ ranging behaviour is both fundamental to understanding its behavioural ecology and a prerequisite to planning its management. Few data exist on the spatial ecology of Cheetahs Acinonyx jubatus outside protected areas, but such areas are particularly important to their conservation. Cheetahs on Namibian farmlands occupied exceptionally large home ranges, averaging 1651 km 2 ( � 1594 km 2 ), with no detectable effect of sex, social grouping or seasonality. Despite such large ranges, Cheetahs tended to utilize intensively only a small fraction of that area: 50% of the fixes were located within an average of 13.9 � 5.3% of the home range. Ranges were not exclusive, overlapping on average by 15.8 � 17.0%, with male Cheetahs showing more intra-sexual range overlap than did females. Coalitions of males appeared to select for a dense, prey-rich habitat, but this preference was not apparent for other social groupings. Conflict with humans is an important contributor to the species’ decline, and these large, overlapping Cheetah home ranges result in the movements of each individual Cheetah encompassing many farms (21 based on the average home-range size). Consequently, many Cheetahs may be exposed to a minority of farmers attempting to kill them, and also that many farmers may see the same Cheetahs, thereby gaining an exaggerated impression of their abundance. Conservation priorities for Cheetahs outside protected areas are the development of techniques for conflict resolution, as well as the maintenance and restoration of suitable habitat and promotion of land-management practices compatible with the continued existence of large carnivores.
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demography of the namibian Cheetah acinonyx jubatus jubatus
Biological Conservation, 2003Co-Authors: Laurie Marker, Amy Dickman, R M Jeo, M G L Mills, David W MacdonaldAbstract:Abstract Namibian Cheetahs have suffered, and continue to suffer, high levels of removal due to conflict with local farmers, and it is important to understand the demography of this population in order to determine its likely persistence. Examination of Cheetahs reported live-trapped or killed by local farmers, combined with subsequent information from radio-telemetry, allowed demographic parameters such as sex ratios, age and social structure, litter size, interbirth intervals and survivorship to be estimated for Cheetahs on Namibian farmlands. Cub mortality was relatively low, but adult mortality was high, particularly for males, and peaked at 5–6 years of age. Neither marking nor relocating Cheetahs seemed to affect survivorship, and there was no difference in survivorship between the sexes. Time spent in captivity did not appear to affect survival after release. These findings will be useful in formulating recommendations regarding the conservation and sustainable utilization of Cheetah populations outside protected areas.
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aspects of the management of Cheetahs acinonyx jubatus jubatus trapped on namibian farmlands
Biological Conservation, 2003Co-Authors: Laurie Marker, Amy Dickman, M G L Mills, David W MacdonaldAbstract:Abstract The Namibian Cheetah population has recently undergone serious decline due to human-mediated removals, and investigating the rates and causes of such removals is an important aspect of the future management of Cheetah populations outside protected areas. We examined Cheetahs that were reported live-trapped or killed on Namibian farmlands between 1991 and 1999. A perceived threat to livestock or game led to the vast majority of live captures and to almost half of the Cheetah deaths investigated. Despite this, livestock predation from Cheetahs appeared to be minimal, and was usually perpetrated by Cheetahs with injuries. Most of the Cheetahs were trapped in groups, and Cheetahs’ relative sociality leads to the easy removal of entire social units. Long-term monitoring must include detailed consideration of these indiscriminate removals, as they involve many Cheetahs, fluctuate between years, often go unreported, and are likely to have a serious impact on Cheetah populations outside protected areas.
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factors influencing perceptions of conflict and tolerance toward Cheetahs on namibian farmlands
Conservation Biology, 2003Co-Authors: Laurie Marker, M G L Mills, David W MacdonaldAbstract:Namibia has the largest remaining population of free-ranging Cheetahs ( Acinonyx jubatus ) in the world, 90% of which are found outside protected areas on commercial farms. We conducted a baseline survey of Namibian farmers between 1991 and 1993, with a yearly follow-up thereafter until 1999, to quantify the percep- tions of farmers toward Cheetahs. Specifically, we sought to identify factors that cause Cheetahs to be perceived as pests and management practices that mitigate this perception. The baseline survey revealed that farmers who re- garded Cheetahs as problems removed an average of 29 Cheetahs annually, whereas those who did not consider them problematic removed a mean of 14 annually. These figures dropped significantly to 3.5 and 2.0 Cheetahs per year after the introduction of educational materials. The perception that Cheetahs are pests was significantly associated with game farms, and the presence of "play trees" on farms emerged as a significant corollary of both negative perceptions and removals of Cheetahs. Between 1991 and 1999, the mean annual number of Cheetah re- movals significantly decreased from 19 to 2.1. Late in the study, Cheetah killing was more closely correlated with perceived problems than in the early years of the study. These findings suggest that although Cheetahs are still per- ceived as a problem, farmers' tolerance toward Cheetahs has increased. Management strategies and economic in- centives that promote Cheetah conservation, such as the formation of conservancies, development of ecotourism, and marketing of "predator-friendly" meat, are essential for conserving Cheetahs outside protected areas.
David E Wildt - One of the best experts on this subject based on the ideXlab platform.
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group management influences reproductive function of the male Cheetah acinonyx jubatus
Reproduction Fertility and Development, 2017Co-Authors: Diana C Koester, Elizabeth W Freeman, David E Wildt, Kimberly A Terrell, Ashley D Franklin, Karen Meeks, Adrienne E CrosierAbstract:Although the free-ranging Cheetah is generally socially solitary, as many as 60% of males live in same-sex (usually sibling) coalitions. Under ex situ conditions, the Cheetah experiences low reproductive success with only ~18% of males having ever produced young. Most male Cheetahs (85%) are managed in captivity in coalitions, but with no data on the influence of social grouping on reproductive parameters. We examined the influence of singleton versus coalition management on various male Cheetah physiological traits, including ejaculate quality and gonadal and adrenal hormone metabolite concentrations. We also assessed behaviour within coalitions for evidence of social hierarchy through initiation of interactions with group mates and relatedness to physiological traits. Ejaculate quality (including total motile and structurally normal spermatozoa per ejaculate) and androgen concentration profiles were higher (P<0.05) in coalition compared with singleton males. These results support the conclusion that testis function in the Cheetah, specifically related to the development of normal, motile spermatozoa and androgen production, is influenced by management with same-sex conspecifics. The findings have implications for ex situ conservation breeding programs by suggesting that reproductive quality can be enhanced through group maintenance of Cheetah males.
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RESEARCH ARTICLE Motile Sperm Output by Male Cheetahs (Acinonyx jubatus) Managed Ex Situ Is Influenced by Public Exposure and Number of Care-Givers
2016Co-Authors: Diana C Koester, Elizabeth W Freeman, David E Wildt, Ashley D Franklin, Janine L Brown, A. Terrell, Adrienne E CrosierAbstract:The collective Cheetah (Acinonyx jubatus) population in zoological institutions has never been self-sustaining because of challenges in natural reproduction. A retrospective analysis of North American zoo-breeding records has revealed that>90 % of litters produced since 2003 occurred in facilities ‘off-display ’ from the public. We examined seminal, endocrine, and behavioral traits of 29 adult male Cheetahs that were: 1) managed in public exhibit or off-display facilities; 2) maintained by different numbers of Cheetah-specific care-givers; and 3) living adjacent to varying numbers of adult conspecifics. Cheetahs housed off-display produced more total motile sperm/ejaculate (P = 0.04) than on-exhibit males. This finding was mirrored in our laboratory’s historical records where two-fold more total motile sperm (P < 0.01) were measured in ejaculates from individuals with no public exposure (n = 43) compared to on-exhibit (n = 116) counterparts. Males at institutions with3 care-givers also produced more total motile sperm/ejaculate (P < 0.03) and spent more time behavior-ally active (P < 0.01) than at facilities using>3 care-givers. Exposure to high numbers of conspecifics within the same institution did not impact (P> 0.05) seminal traits, and pres
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continued decline in genetic diversity among wild Cheetahs acinonyx jubatus without further loss of semen quality
Biological Conservation, 2016Co-Authors: Laurie Marker, Stephen J Obrien, David E Wildt, Kimberly A Terrell, Adrienne E Crosier, Nicola M Anthony, Warren E. JohnsonAbstract:As a well-studied felid with limited genetic diversity, the Cheetah (Acinonyx jubatus) has shaped much of the scientific debate surrounding inbreeding depression. The species survived a population bottleneck ~ 12,000 years ago and was extirpated from > 75% of its historical range in the last century. Modern Cheetahs produce poor-quality semen, a presumed manifestation of inbreeding depression. Within Felidae, a positive association between genetic diversity and semen quality is well supported by pedigree data and inter-species comparisons. However, this relationship has never been examined among individual Cheetahs. Furthermore, whether ongoing population declines are exacerbating inbreeding depression in wild or captive Cheetah populations is unknown. Using 12 microsatellite markers, we evaluated the relationship between heterozygosity and reproductive traits among wild (n = 54) and captive (n = 43) male Cheetahs born from 1976–2007. We tested the hypotheses that genetic diversity has declined over the last ~ 30 years and is positively correlated with semen quality/breeding success in the Cheetah. Findings revealed that genetic diversity has decreased in the wild, but not captive, population. Unexpectedly, heterozygosity was lower in proven versus unproven breeders and did not correlate with semen quality. A small proportion of all males (< 10%) produced relatively high quality ejaculates, with sperm traits similar to those of non-inbred felid species. These data suggest a more complex relationship between inbreeding and male Cheetah reproductive traits than previously appreciated. Intensive management of captive Cheetahs appears to be minimizing inbreeding, whereas the continued erosion of genetic diversity in wild males is of conservation concern.
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motile sperm output by male Cheetahs acinonyx jubatus managed ex situ is influenced by public exposure and number of care givers
PLOS ONE, 2015Co-Authors: Diana C Koester, Elizabeth W Freeman, David E Wildt, Kimberly A Terrell, Ashley D Franklin, Janine L Brown, Adrienne E CrosierAbstract:The collective Cheetah (Acinonyx jubatus) population in zoological institutions has never been self-sustaining because of challenges in natural reproduction. A retrospective analysis of North American zoo-breeding records has revealed that >90% of litters produced since 2003 occurred in facilities 'off-display' from the public. We examined seminal, endocrine, and behavioral traits of 29 adult male Cheetahs that were: 1) managed in public exhibit or off-display facilities; 2) maintained by different numbers of Cheetah-specific care-givers; and 3) living adjacent to varying numbers of adult conspecifics. Cheetahs housed off-display produced more total motile sperm/ejaculate (P = 0.04) than on-exhibit males. This finding was mirrored in our laboratory's historical records where two-fold more total motile sperm (P 3 care-givers. Exposure to high numbers of conspecifics within the same institution did not impact (P > 0.05) seminal traits, and presence of the public, care-giver number, or animals/facility had no influence (P > 0.05) on androgen or glucocorticoid excretion or other behavioral metrics. Findings indicate that male Cheetahs are sensitive to general public exposure and too many care-givers, resulting in compromised motile sperm output/ejaculate with mechanism of action unrelated to altered androgen or glucocorticoid excretion.
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ejaculate traits in the namibian Cheetah acinonyx jubatus influence of age season and captivity
Reproduction Fertility and Development, 2007Co-Authors: Jogayle Howard, Laurie Marker, Adrienne E Crosier, Budhan S Pukazhenthi, Josephine N Henghali, David E WildtAbstract:The objective was to examine the influence of animal age, season and captivity status on seminal quality in wild-born Cheetahs (Acinonyx jubatus) in Namibia, Africa. Animals were divided into three age categories: juvenile (14-24 months; n = 16 males, 23 ejaculates); adult (25-120 months; n = 76 males, 172 ejaculates); and aged (>120 months; n = 5 males, 5 ejaculates). Seasons were categorised into hot-wet (January-April), cold-dry (May-August) and hot-dry (September-December). A comparison between freshly wild-caught (n = 29 males, 41 ejaculates) and captive-held Cheetahs (n = 68 males, 159 ejaculates) was also conducted. Raw ejaculates contained 69.0 +/- 1.1% motile spermatozoa (mean +/- s.e.m.) with 73.6 +/- 1.5% of these cells containing an intact acrosome. Overall, 18.4 +/- 0.9% of spermatozoa were morphologically normal, with midpiece anomalies being the most prevalent (approximately 39%) defect. Juvenile Cheetahs produced ejaculates with poorer sperm motility, forward progressive status, lower seminal volume and fewer total motile spermatozoa than adult and aged animals. Spermatogenesis continued unabated throughout the year and was minimally influenced by season. Proportions of sperm malformations were also not affected by season. Ejaculates from captive Cheetahs had increased volume and intact acrosomes, but lower sperm density than wild-caught counterparts. In summary, Namibian Cheetahs produce an extraordinarily high proportion of pleiomorphic spermatozoa regardless of age, season or living (captive versus free-ranging) status. Young males less than 2 years of age produce poorer ejaculate quality than adult and aged males. Because (1) all study animals were wild born and (2) there was little difference between freshly caught males and those maintained in captivity for protracted periods, our results affirm that teratospermia in the Cheetah is mostly genetically derived. It also appears that an ex situ environment for the Namibian Cheetah can ensure sperm quality comparable with that for free-living males.
Adrienne E Crosier - One of the best experts on this subject based on the ideXlab platform.
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group management influences reproductive function of the male Cheetah acinonyx jubatus
Reproduction Fertility and Development, 2017Co-Authors: Diana C Koester, Elizabeth W Freeman, David E Wildt, Kimberly A Terrell, Ashley D Franklin, Karen Meeks, Adrienne E CrosierAbstract:Although the free-ranging Cheetah is generally socially solitary, as many as 60% of males live in same-sex (usually sibling) coalitions. Under ex situ conditions, the Cheetah experiences low reproductive success with only ~18% of males having ever produced young. Most male Cheetahs (85%) are managed in captivity in coalitions, but with no data on the influence of social grouping on reproductive parameters. We examined the influence of singleton versus coalition management on various male Cheetah physiological traits, including ejaculate quality and gonadal and adrenal hormone metabolite concentrations. We also assessed behaviour within coalitions for evidence of social hierarchy through initiation of interactions with group mates and relatedness to physiological traits. Ejaculate quality (including total motile and structurally normal spermatozoa per ejaculate) and androgen concentration profiles were higher (P<0.05) in coalition compared with singleton males. These results support the conclusion that testis function in the Cheetah, specifically related to the development of normal, motile spermatozoa and androgen production, is influenced by management with same-sex conspecifics. The findings have implications for ex situ conservation breeding programs by suggesting that reproductive quality can be enhanced through group maintenance of Cheetah males.
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RESEARCH ARTICLE Motile Sperm Output by Male Cheetahs (Acinonyx jubatus) Managed Ex Situ Is Influenced by Public Exposure and Number of Care-Givers
2016Co-Authors: Diana C Koester, Elizabeth W Freeman, David E Wildt, Ashley D Franklin, Janine L Brown, A. Terrell, Adrienne E CrosierAbstract:The collective Cheetah (Acinonyx jubatus) population in zoological institutions has never been self-sustaining because of challenges in natural reproduction. A retrospective analysis of North American zoo-breeding records has revealed that>90 % of litters produced since 2003 occurred in facilities ‘off-display ’ from the public. We examined seminal, endocrine, and behavioral traits of 29 adult male Cheetahs that were: 1) managed in public exhibit or off-display facilities; 2) maintained by different numbers of Cheetah-specific care-givers; and 3) living adjacent to varying numbers of adult conspecifics. Cheetahs housed off-display produced more total motile sperm/ejaculate (P = 0.04) than on-exhibit males. This finding was mirrored in our laboratory’s historical records where two-fold more total motile sperm (P < 0.01) were measured in ejaculates from individuals with no public exposure (n = 43) compared to on-exhibit (n = 116) counterparts. Males at institutions with3 care-givers also produced more total motile sperm/ejaculate (P < 0.03) and spent more time behavior-ally active (P < 0.01) than at facilities using>3 care-givers. Exposure to high numbers of conspecifics within the same institution did not impact (P> 0.05) seminal traits, and pres
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continued decline in genetic diversity among wild Cheetahs acinonyx jubatus without further loss of semen quality
Biological Conservation, 2016Co-Authors: Laurie Marker, Stephen J Obrien, David E Wildt, Kimberly A Terrell, Adrienne E Crosier, Nicola M Anthony, Warren E. JohnsonAbstract:As a well-studied felid with limited genetic diversity, the Cheetah (Acinonyx jubatus) has shaped much of the scientific debate surrounding inbreeding depression. The species survived a population bottleneck ~ 12,000 years ago and was extirpated from > 75% of its historical range in the last century. Modern Cheetahs produce poor-quality semen, a presumed manifestation of inbreeding depression. Within Felidae, a positive association between genetic diversity and semen quality is well supported by pedigree data and inter-species comparisons. However, this relationship has never been examined among individual Cheetahs. Furthermore, whether ongoing population declines are exacerbating inbreeding depression in wild or captive Cheetah populations is unknown. Using 12 microsatellite markers, we evaluated the relationship between heterozygosity and reproductive traits among wild (n = 54) and captive (n = 43) male Cheetahs born from 1976–2007. We tested the hypotheses that genetic diversity has declined over the last ~ 30 years and is positively correlated with semen quality/breeding success in the Cheetah. Findings revealed that genetic diversity has decreased in the wild, but not captive, population. Unexpectedly, heterozygosity was lower in proven versus unproven breeders and did not correlate with semen quality. A small proportion of all males (< 10%) produced relatively high quality ejaculates, with sperm traits similar to those of non-inbred felid species. These data suggest a more complex relationship between inbreeding and male Cheetah reproductive traits than previously appreciated. Intensive management of captive Cheetahs appears to be minimizing inbreeding, whereas the continued erosion of genetic diversity in wild males is of conservation concern.
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motile sperm output by male Cheetahs acinonyx jubatus managed ex situ is influenced by public exposure and number of care givers
PLOS ONE, 2015Co-Authors: Diana C Koester, Elizabeth W Freeman, David E Wildt, Kimberly A Terrell, Ashley D Franklin, Janine L Brown, Adrienne E CrosierAbstract:The collective Cheetah (Acinonyx jubatus) population in zoological institutions has never been self-sustaining because of challenges in natural reproduction. A retrospective analysis of North American zoo-breeding records has revealed that >90% of litters produced since 2003 occurred in facilities 'off-display' from the public. We examined seminal, endocrine, and behavioral traits of 29 adult male Cheetahs that were: 1) managed in public exhibit or off-display facilities; 2) maintained by different numbers of Cheetah-specific care-givers; and 3) living adjacent to varying numbers of adult conspecifics. Cheetahs housed off-display produced more total motile sperm/ejaculate (P = 0.04) than on-exhibit males. This finding was mirrored in our laboratory's historical records where two-fold more total motile sperm (P 3 care-givers. Exposure to high numbers of conspecifics within the same institution did not impact (P > 0.05) seminal traits, and presence of the public, care-giver number, or animals/facility had no influence (P > 0.05) on androgen or glucocorticoid excretion or other behavioral metrics. Findings indicate that male Cheetahs are sensitive to general public exposure and too many care-givers, resulting in compromised motile sperm output/ejaculate with mechanism of action unrelated to altered androgen or glucocorticoid excretion.
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ejaculate traits in the namibian Cheetah acinonyx jubatus influence of age season and captivity
Reproduction Fertility and Development, 2007Co-Authors: Jogayle Howard, Laurie Marker, Adrienne E Crosier, Budhan S Pukazhenthi, Josephine N Henghali, David E WildtAbstract:The objective was to examine the influence of animal age, season and captivity status on seminal quality in wild-born Cheetahs (Acinonyx jubatus) in Namibia, Africa. Animals were divided into three age categories: juvenile (14-24 months; n = 16 males, 23 ejaculates); adult (25-120 months; n = 76 males, 172 ejaculates); and aged (>120 months; n = 5 males, 5 ejaculates). Seasons were categorised into hot-wet (January-April), cold-dry (May-August) and hot-dry (September-December). A comparison between freshly wild-caught (n = 29 males, 41 ejaculates) and captive-held Cheetahs (n = 68 males, 159 ejaculates) was also conducted. Raw ejaculates contained 69.0 +/- 1.1% motile spermatozoa (mean +/- s.e.m.) with 73.6 +/- 1.5% of these cells containing an intact acrosome. Overall, 18.4 +/- 0.9% of spermatozoa were morphologically normal, with midpiece anomalies being the most prevalent (approximately 39%) defect. Juvenile Cheetahs produced ejaculates with poorer sperm motility, forward progressive status, lower seminal volume and fewer total motile spermatozoa than adult and aged animals. Spermatogenesis continued unabated throughout the year and was minimally influenced by season. Proportions of sperm malformations were also not affected by season. Ejaculates from captive Cheetahs had increased volume and intact acrosomes, but lower sperm density than wild-caught counterparts. In summary, Namibian Cheetahs produce an extraordinarily high proportion of pleiomorphic spermatozoa regardless of age, season or living (captive versus free-ranging) status. Young males less than 2 years of age produce poorer ejaculate quality than adult and aged males. Because (1) all study animals were wild born and (2) there was little difference between freshly caught males and those maintained in captivity for protracted periods, our results affirm that teratospermia in the Cheetah is mostly genetically derived. It also appears that an ex situ environment for the Namibian Cheetah can ensure sperm quality comparable with that for free-living males.
M G L Mills - One of the best experts on this subject based on the ideXlab platform.
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spatial ecology of Cheetahs on north central namibian farmlands
Journal of Zoology, 2008Co-Authors: Laurie Marker, Amy Dickman, R M Jeo, M G L Mills, David W MacdonaldAbstract:Knowledge of a species’ ranging behaviour is both fundamental to understanding its behavioural ecology and a prerequisite to planning its management. Few data exist on the spatial ecology of Cheetahs Acinonyx jubatus outside protected areas, but such areas are particularly important to their conservation. Cheetahs on Namibian farmlands occupied exceptionally large home ranges, averaging 1651 km 2 ( � 1594 km 2 ), with no detectable effect of sex, social grouping or seasonality. Despite such large ranges, Cheetahs tended to utilize intensively only a small fraction of that area: 50% of the fixes were located within an average of 13.9 � 5.3% of the home range. Ranges were not exclusive, overlapping on average by 15.8 � 17.0%, with male Cheetahs showing more intra-sexual range overlap than did females. Coalitions of males appeared to select for a dense, prey-rich habitat, but this preference was not apparent for other social groupings. Conflict with humans is an important contributor to the species’ decline, and these large, overlapping Cheetah home ranges result in the movements of each individual Cheetah encompassing many farms (21 based on the average home-range size). Consequently, many Cheetahs may be exposed to a minority of farmers attempting to kill them, and also that many farmers may see the same Cheetahs, thereby gaining an exaggerated impression of their abundance. Conservation priorities for Cheetahs outside protected areas are the development of techniques for conflict resolution, as well as the maintenance and restoration of suitable habitat and promotion of land-management practices compatible with the continued existence of large carnivores.
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Cheetah acinonyx jubatus feeding ecology in the kruger national park and a comparison across african savanna habitats is the Cheetah only a successful hunter on open grassland plains
Wildlife Biology, 2004Co-Authors: M G L Mills, L S Broomhall, J T Du ToitAbstract:The literature on Cheetah Acinonyx jubatus ecology is dominated by studies on the Serengeti Plains (SNP) in East Africa. Because of this and the Cheetah's hunting strategy it is generally considered to be a predator that prefers open grassland plains. However, Cheetahs also inhabit a range of bush, scrub and woodland habitats. A field study using direct observations of radio-collared individuals in the woodland savanna habitat of the Kruger National Park (KNP), South Africa, and a literature review of studies across savanna habitats examined Cheetah predation, hunting behaviour and habitat use in relation to prey composition, cover availability and kleptoparasitism. The Cheetah's main prey is medium-sized herbivores, with a bias towards male prey. The group size and sex of the hunting Cheetah may influence the results of prey selection studies as male coalitions tend to take larger prey than females. Cheetahs initiated more hunts and had a higher success rate in the open woodland savanna of the KNP compared to other available habitats with thicker bush, and in other wooded savanna areas they also prefer more open habitat for hunting. Although they appear to have shorter chase distances in more wooded habitats, hunting success appears to be slightly higher in open grassland habitat. Woody vegetation appears to obstruct the Cheetah's high-speed hunting strategy, thereby lowering hunting success. However, Cheetahs use cover for stalking prey and open habitats with bordering woodlands, or patches of cover are considered preferred Cheetah habitats. In these habitats, Cheetahs can stalk closer to their prey using available cover, but also successfully pursue their prey into available open spaces. Across African savanna ecosystems, Cheetahs appear to be kleptoparasitised less in more wooded habitats. Therefore they may also prefer these habitats because they provide greater concealment from kleptoparasites. Our study suggests that the Cheetah is more adaptable to habitat variability than is often thought and is not only a successful hunter on open grassland plains.
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demography of the namibian Cheetah acinonyx jubatus jubatus
Biological Conservation, 2003Co-Authors: Laurie Marker, Amy Dickman, R M Jeo, M G L Mills, David W MacdonaldAbstract:Abstract Namibian Cheetahs have suffered, and continue to suffer, high levels of removal due to conflict with local farmers, and it is important to understand the demography of this population in order to determine its likely persistence. Examination of Cheetahs reported live-trapped or killed by local farmers, combined with subsequent information from radio-telemetry, allowed demographic parameters such as sex ratios, age and social structure, litter size, interbirth intervals and survivorship to be estimated for Cheetahs on Namibian farmlands. Cub mortality was relatively low, but adult mortality was high, particularly for males, and peaked at 5–6 years of age. Neither marking nor relocating Cheetahs seemed to affect survivorship, and there was no difference in survivorship between the sexes. Time spent in captivity did not appear to affect survival after release. These findings will be useful in formulating recommendations regarding the conservation and sustainable utilization of Cheetah populations outside protected areas.
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aspects of the management of Cheetahs acinonyx jubatus jubatus trapped on namibian farmlands
Biological Conservation, 2003Co-Authors: Laurie Marker, Amy Dickman, M G L Mills, David W MacdonaldAbstract:Abstract The Namibian Cheetah population has recently undergone serious decline due to human-mediated removals, and investigating the rates and causes of such removals is an important aspect of the future management of Cheetah populations outside protected areas. We examined Cheetahs that were reported live-trapped or killed on Namibian farmlands between 1991 and 1999. A perceived threat to livestock or game led to the vast majority of live captures and to almost half of the Cheetah deaths investigated. Despite this, livestock predation from Cheetahs appeared to be minimal, and was usually perpetrated by Cheetahs with injuries. Most of the Cheetahs were trapped in groups, and Cheetahs’ relative sociality leads to the easy removal of entire social units. Long-term monitoring must include detailed consideration of these indiscriminate removals, as they involve many Cheetahs, fluctuate between years, often go unreported, and are likely to have a serious impact on Cheetah populations outside protected areas.
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home range and habitat use by Cheetahs acinonyx jubatus in the kruger national park
Journal of Zoology, 2003Co-Authors: L S Broomhall, M G L Mills, J T Du ToitAbstract:Cheetah Acinonyx jubatus home-range size and habitat use were analysed using radio-tracking data collected in the southern district of the Kruger National Park (KNP) between 1987 and 1990. Meaningful estimates of home-range size, using the 95% minimum convex polygon method, were 126 km2 for a three-male Cheetah coalition, 195 km2 for a solitary male, and 150 km2 and 171 km2 for two female Cheetahs. Although Cheetahs used all habitats according to their availability, they did show a preference for open savanna habitat because their core or total home ranges centred on these habitats. Female Cheetahs used denser woodland habitat more frequently than males, as they seemed to be influenced by the distribution of their main prey, impala Aepyceros melampus, which also preferred denser woodland habitat.