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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Age assignment to individual African lions

Ferreira, S, Funston, PJ 01 April 2010 (has links)
Abstract Assigning ages to lions (Panthera leo) requires the use of subjective and objective criteria, and is useful for conservation decision-making in that age distributions can be defined from which demographic profiles can be extracted. We collated all age assignment criteria and found that a constraint of most objective criteria is that they require immobilized or dead specimens to measure. Furthermore, nearly all criteria used lions with assumed ages to construct relationships or narrative descriptions. We show that digital photogrammetry provides digitally-derived measures of shoulder heights similar to that of linearly derived measures. In addition, such shoulder heights did not differ between captive and free ranging lions, or between different regions in Africa. Variation in shoulder height is primarily associated with sex-specific age. Age, using the von Bertalanffy growth curve, explained 92% and 97% of the variation in female and male shoulder height, a skeletal measure not strongly affected by resource availability. Simulations suggest that age assignment is relatively accurate for females and males with shoulder heights up to 70 cm and 95 cm, respectively. Thus for lions younger than two years of age objective criteria gives most precise estimates, while subjective criteria are more suitable for older lions.
2

Effect of a Temporary Hunting Ban on the Demography of African Lions (Panthera Leo) Using a Protected Area

Mweetwa, Thandiwe, Mweetwa, Thandiwe January 2016 (has links)
Large carnivores are in decline throughout their range primarily due to anthropogenic influences. This is a concern because these species have high social, economic and ecological value. African lion (Panthera leo) populations are in decline in most parts of the continent and this has been attributed largely to habitat loss, habitat fragmentation, wire snare poaching, black market trafficking in lion parts, retaliatory killings, and poorly regulated trophy hunting. In order to implement effective lion conservation actions, the effect of each factor on lion demography or population dynamics must be well understood. In the past, most studies have used indirect methods to quantify the effects of hunting on lion demography. The temporary ban on lion hunting in Zambia allowed me to study directly how removing a key source of mortality, for males in particular, changed the demography. Using data collected from 2008-2015, I studied how the lion population in and around South Luangwa National Park, Zambia responded to a 3-year moratorium on lion trophy hunting implemented in 2013. For the duration of the study ban, I monitored 386 known individuals in 19 prides and 15 male coalitions. Reproductive activity as represented by cub production appeared to improve after the hunting ban and the number of individually identifiable lions in the study area steadily increased from 88 in 2008 to 197 in 2015. Using a Cormack-Jolly-Seber model, I found that apparent annual survival increased in the absence of hunting for all adult male age classes. The temporary ban on hunting was lifted in 2016 and I recommend that quotas remain conservative in order to allow more time for the population to recover, particularly in the adult male age classes. Better monitoring protocols should also be implemented to promote compliance with hunting regulations.
3

Arterial supply and histology of the female reproductive organs of the African lion (Panthera leo)

Hartman, Marthinus Jacobus January 2013 (has links)
This masters project was undertaken to have a better knowledge of the female lion reproductive tract and to equip the author for future surgical studies on this organ system. The objectives of this study were to describe the arterial supply and histology of the female reproductive organs of the African lion. The reproductive organs of three embalmed cadavers and two fresh carcasses from three-year-old known aged nulliparous lionesses weighing between 120 kg and 140 kg were studied. The project was approved by the Animal Use and Care Committee and Research Committee of the University of Pretoria (protocol number V038-09). The arterial supply of the reproductive organs was studied and described in situ and after removal and histology was subsequently performed. A novel technique in Veterinary anatomy involving the maceration of a silicone cast was used in the two fresh carcasses and all five specimens were incorporated in the comparative and arterial studies. Histology was performed on organs from the three embalmed cadavers. The anatomical information obtained during this study was subsequently applied in a surgical study on sixteen lionesses using laparoscopy to perform laparoscopic ovariectomy and salpingectomy. The availability of these two laparoscopic procedures subsequently led to a wider interest to its application in population control of lions in the smaller national parks of South Africa. / Dissertation (MSc)--University of Pretoria, 2013. / gm2014 / Anatomy and Physiology / unrestricted
4

Carnassial Microwear and Dietary Behaviour in Large Carnivorans

Schubert, B. W., Ungar, P. S., DeSantis, L. R. 01 March 2010 (has links)
This paper presents the first analysis of dental microwear textures of carnivorans. Carnassial microwear is examined for three large carnivorans, the cheetah Acinonyx jubatus, African lion Panthera leo and spotted hyaena Crocuta crocuta using dental microwear texture analysis, which combines confocal microscopy with the study of scale-sensitive fractal geometry. Results indicate significant differences in the microscopic wear textures of these carnivores consistent with dissimilarities in their reported feeding behaviours. Acinonyx jubatus carnassial shearing facets are characterized by low surface texture complexity and high anisotropy, while P. leo and C. crocuta evince less wear texture anisotropy and more complexity. Panthera leo and C. crocuta have more heavily pitted surfaces, a wider size range of wear features and scratches that vary in their orientations relative to the long axis of the carnassial blade. Further, C. crocuta is most variable in overall surface complexity and also has the highest average complexity values. These results are consistent with differences in bone consumption rates among the three species, wherein cheetahs typically avoid bone, lions triturate it on occasion and spotted hyaenas comminute it more often. Incidences of bone consumption in carnivores reflect degree and/or type of carcass utilization and can be used as a general guide for niche partitioning. Thus, the application of microwear analyses to carnivores can be used to interpret competition and niche position within a guild of fossil carnivores across space and through time.
5

Morphology of the female reproductive organs of the African lion (Panthera leo)

Hartman, Marthinus Jacobus January 2012 (has links)
The objectivie of this study was to describe the splanchnology and topography of the female reproductive organs of the African lion. The reproductive organs of three embalmed cadavers from three-year-old known aged nulliparous lionesses weighing between 120 kg and 140 kg were studied. Two fresh carcasses from another study were used for some of the topographical photos since these rendered better quality images. The project was approved by the Animal Use and Care Committee and Research Committee of the University of Pretoria (protocol number V038-09). The topography and splanchnology of the reproductive organs were studied and described in situ and after removal. The kidneys were located far caudally in relation to the thirteenth ribs with the left kidney further caudal. The suspensory ligament was very well developed. It originated in a fan-like manner from the dorso-lateral abdominal wall lateral to the kidney extending up to a few centimetres cranial to the kidney. The proper ligament of the ovary was well developed and consisted of several clearly distinguishable bands. The broad ligament resembled that of the cat with the exeption of the cranial part of the mesovarium being very well developed. The round ligament was well developed and inserted on the medial femoral fascia. It therefore did not extend to the vulva as in other canine and feline species. The left ovary was longer, wider and heavier than its right counterpart and the ovaries were relatively small in relation to body weight. The ovarian bursa had a short mesosalpinx that did not cover any part of the ovary and the fimbriae extended the entire length of the ovary. The urethral tuberculum as well as the urethral crest was very well developed. The left uterine horn was longer than the right and the tip of the uterine horn was located dorsal to the proper ligament. The uterine tube was prominently convoluted, situated entirely on the lateral aspect of the ovary and was found to open directly into the tip of the uterine horn and not onto a papilla. The female reproductive organs of the African lion resemble that of the domestic cat and dog with some major differences especially to the size and development of certain structures. The clinical relevance of these differences has to be debated and some thoughts might include the following: 1) does the suspensory and proper ligaments of the gravid uterus contract to suspend the entire uterus closer to the body wall during hunting since the lioness is the primary hunter in the pride? 2) does the lioness have to roll on her back and extend her back legs after mating to facilitate sperm entering the dorsally located tip of the uterine horn while the round ligament stabilises the terminal part of the uterine horn, and does this have a bearing on the fact that multiple copulations are required over a prolonged period for conception by lions? 3) do more ovulations take place from the bigger left ovary and? 4) are more conceptusses borne by the longer left uterine horn? The anatomical information obtained during this study was subsequently applied in a surgical study on sixteen lionesses using laparoscopy to perform laparoscopic ovariectomy and salpingectomy. The availability of these two laparoscopic procedures subsequently led to a wider interest to its application in population control of lions in the smaller national parks of South Africa. / Dissertation (MMedVet)--University of Pretoria, 2012. / gm2014 / Companion Animal Clinical Studies / unrestricted
6

Niche segregation by cheetah (Acinonyx jubatus) as a mechanism for co-existence with lion (Panthera leo) and spotted hyaena (Crocuta crocuta)

Broekhuis, Femke January 2012 (has links)
Intraguild competition and predation have been recognised as important ecological factors influencing the population dynamics of carnivores. The effects of these interactions are often asymmetrical due to a size-related dominancy hierarchy. However, it has been suggested that competitively subordinate carnivores can minimise the costs of predation and competition through spatial and temporal avoidance. Here I investigate the ecological and behavioural mechanisms by which cheetahs (Acinonyx jubatus) coexist with competitively stronger lions (Panthera leo) and spotted hyaenas (Crocuta crocuta). Fieldwork was carried out in the Okavango Delta, northern Botswana, between October 2008 and August 2011. A total of 20 Global Positioning System (GPS) radio-collars were fitted on all known cheetahs (n=6), lion prides (n=5) and spotted hyaena clans (n=6) in the study area (approx. 3 000 km<sup>2</sup>). Pre-programmed radio-collars recorded locations and activity continuously for each individual and these data were complemented with direct behavioural observations. Cheetah data were analysed with respect to the temporal and spatial likelihood of encountering lions and spotted hyaenas. Results suggest that the response to the risks posed by other predators is species-specific, habitat-specific and dependent on the immediacy of the risk. Resource partitioning was not the main mechanism for coexistence as cheetahs overlapped extensively with lions and spotted hyaenas in time, space and habitat use. Instead, cheetahs adjusted their spatial distribution in response to immediate risks or adapted their habitat use depending on their vulnerability (e.g. behaviours such as feeding or with differing levels of moonlight at night). In general, cheetah temporal and spatial distribution is a hierarchal process, firstly driven by resource acquisition and thereafter fine-tuned by predator avoidance. In addition, habitat heterogeneity seemed to be key in facilitating coexistence. Understanding the behavioural mechanisms that interacting apex predators adopt to regulate these negative interactions could be crucial to carnivore conservation, especially as human-related habitat loss is forcing species into ever smaller areas.

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