Publications

TitleAbstractYear(sorted ascending)
Filter
PMID
Filter
results of the third reproductive assessment survey of north american asian (elephas maximus) and african (loxodonta africana) female elephants.a written survey assessed reproductive status of female asian and african elephants in aza/ssp facilities in 2008, and data were compared to surveys conducted in 2002 and 2005. results showed that ovarian acyclicity rates across the surveys remained unchanged for asian (13.3, 10.9 and 11.1%) and african (22.1, 31.2 and 30.5%) elephants, respectively (p>0.05), but were higher overall for african compared to asian elephants (p<0.05). in 2008, the percentages of asian and african elephants with irr ...201121319213
a preliminary analysis of the immunoglobulin genes in the african elephant (loxodonta africana).the genomic organization of the igh (immunoglobulin heavy chain), ig? (immunoglobulin kappa chain), and ig? (immunoglobulin lambda chain) loci in the african elephant (loxodonta africana) was annotated using available genome data. the elephant igh locus on scaffold 57 spans over 2,974 kb, and consists of at least 112 v(h) gene segments, 87 d(h) gene segments (the largest number in mammals examined so far), six j(h) gene segments, a single µ, a d remnant, and eight ? genes (a and e genes are miss ...201121364892
leadership in elephants: the adaptive value of age.the value of age is well recognized in human societies, where older individuals often emerge as leaders in tasks requiring specialized knowledge, but what part do such individuals play in other social species? despite growing interest in how effective leadership might be achieved in animal social systems, the specific role that older leaders may play in decision-making has rarely been experimentally investigated. here, we use a novel playback paradigm to demonstrate that in african elephants (lo ...201121411454
a questionnaire-based evaluation of the veterinary cordon fence separating wildlife and livestock along the boundary of the kruger national park, south africa.veterinary cordon fences are used in southern africa to separate wildlife from domestic animals in order to prevent transmission of infectious diseases. such fences are a control method recognized by the world organization for animal health (oie) for establishing disease-free zones in beef exporting countries. however, few studies have evaluated the ecological impact of these physical barriers or their effectiveness at a multispecies level. we examined the permeability of one such barrier, along ...201121536336
placentation in the african elephant (loxodonta africana). v. the trophoblast secretes placental lactogen.to determine if elephant placenta secretes a lactogenic hormone which may function as the principal luteotrophin to maintain ovarian luteal function throughout gestation. study design and main outcome measures: to label biopsies of endometrium and placenta recovered from african elephant culled professionally throughout gestation with an anti-human prolactin polyclonal antibody in a conventional immunocytochemical staining technique.201121550657
secretory pattern of inhibin during estrous cycle and pregnancy in african (loxodonta africana) and asian (elephas maximus) elephants.the ovary of female elephants has multiple corpora lutea (cl) during the estrous cycle and gestation. the previous reports clearly demonstrated that inhibin was secreted from lutein cells as well as granulosa cells of antral follicles in cyclic asian elephants. the aim of this study is to investigate the inhibin secretion during the pregnancy in african and asian elephants. two african elephants and two asian elephants were subjected to this study. circulating levels of immunoreactive (ir-) inhi ...201121812022
effects of economic downturns on mortality of wild african elephants.declines in economic activity and associated changes in human livelihood strategies can increase threats of species overexploitation. this is exemplified by the effects of economic crises, which often drive intensification of subsistence poaching and greater reliance on natural resources. whereas development theory links natural resource use to social-economic conditions, few empirical studies of the effect of economic downturns on wild animal species have been conducted. i assessed the relation ...201121790785
volumetric analysis of the african elephant ventricular system.this study used magnetic resonance imaging (mri) to determine the volume of the ventricular system in the brain of three adult male african elephants (loxodonta africana). the ventricular system of the elephant has a volume of ôê+240 ml, an order of magnitude larger than that seen in the adult human. despite this large size, allometric analysis indicates that the volume of the ventricles in the elephant is what one would expect for a mammal with an ôê+5 kg brain. interestingly, our comparison wi ...201121714111
a cross-species comparison of escape from x inactivation in eutheria: implications for evolution of x chromosome inactivation.sex chromosome dosage compensation in both eutherian and marsupial mammals is achieved by x chromosome inactivation (xci)-transcriptional repression that silences one of the two x chromosomes in the somatic cells of females. we recently used rna fluorescent in situ hybridization (fish) to show, in individual nuclei, that marsupial x inactivation (in the absence of xist) occurs on a gene-by-gene basis, and that escape from inactivation is stochastic and independent of gene location. in the absenc ...201121947602
the secretory pattern and source of immunoreactive prolactin in pregnant african (loxodonta africana) and asian (elephas maximus) elephants.the objective of the present study was to define the secretion of prolactin (prl) in pregnant african and asian elephants. levels of immunoreactive (ir-) prl in serum and placental homogenates were measured by a heterologous radioimmunoassay (ria) based on an ovine and human ria system, and the localization of immunoreactive (ir-) prl in the placenta was detected by immunohistochemistry using anti-human prl. circulating ir-prolactin clearly showed a biphasic pattern during pregnancy in african a ...201122075560
proteomic analysis of a pleistocene mammoth femur reveals more than one hundred ancient bone proteins.we used high-sensitivity, high-resolution tandem mass spectrometry to shotgun sequence ancient protein remains extracted from a 43 000 year old woolly mammoth ( mammuthus primigenius ) bone preserved in the siberian permafrost. for the first time, 126 unique protein accessions, mostly low-abundance extracellular matrix and plasma proteins, were confidently identified by solid molecular evidence. among the best characterized was the carrier protein serum albumin, presenting two single amino acid ...201122103443
inferring ecological and behavioral drivers of african elephant movement using a linear filtering approach.understanding the environmental factors influencing animal movements is fundamental to theoretical and applied research in the field of movement ecology. studies relating fine-scale movement paths to spatiotemporally structured landscape data, such as vegetation productivity or human activity, are particularly lacking despite the obvious importance of such information to understanding drivers of animal movement. in part, this may be because few approaches provide the sophistication to characteri ...201121905431
Preliminary validation of assays to measure parameters of calcium metabolism in captive Asian and African elephants in western Europe.Hypocalcemia is a well known cause of dystocia in animals, including elephants in captivity. In order to study calcium metabolism in elephants, it is of utmost importance to use properly validated assays, as these might be prone to specific matrix effects in elephant blood. The aim of the current study was to conduct preliminary work for validation of various parameters involved in calcium metabolism in both blood and urine of captive elephants. Basal values of these parameters were compared bet ...201121908279
game over! wildlife collapse in northern central african republic.the wildlife populations of northern central african republic (car) have long suffered intense uncontrolled hunting. socio-political turmoil in northern car that started in 2002 resulted in a rebellion in 2006. an aerial sample count was carried out in northern car after the ceasefire to assess the impact of this troubled period on wildlife. the survey was flown at the end of the dry season in february-march 2010. it covered a landscape complex of 95,000 km² comprising national parks, hunting re ...201122170159
food preference, keeper ratings, and reinforcer effectiveness in exotic animals: the value of systematic testing.food preference describes the behavior of selecting between items for consumption; reinforcer effectiveness is the functional effect of that item in controlling behavior. food preference and reinforcer effectiveness were examined in giant pandas (ailuropoda melanoleuca) and african elephants (loxodonta africana). a pairwise comparison between food items was used to assess food preference. high-, moderate-, and low-preference items were selected and tested for reinforcer effectiveness. high-prefe ...201121191846
prevalence of methicillin-resistant staphylococcus aureus in mammals of the royal zoological society of antwerp, belgium.contrary to the numerous reports on methicillin-resistant staphylococcus aureus (mrsa) in domestic animals, only three articles concerning zoo animals are documented in the literature. a skin infection of an african elephant (loxodonta africana) calf was most likely acquired from an infected caretaker. another zoo detected mrsa in the rumen content of a mouflon (ovis aries), and, in a third facility, it was reported in a fistulous wound at the coronary band of a digit of an indian rhinoceros (rh ...201222448524
animal perception of seasonal thresholds: changes in elephant movement in relation to rainfall patterns.the identification of temporal thresholds or shifts in animal movement informs ecologists of changes in an animal's behaviour, which contributes to an understanding of species' responses in different environments. in african savannas, rainfall, temperature and primary productivity influence the movements of large herbivores and drive changes at different scales. here, we developed a novel approach to define seasonal shifts in movement behaviour by examining the movements of a highly mobile herbi ...201222761680
elephant transcriptome provides insights into the evolution of eutherian placentation.the chorioallantoic placenta connects mother and fetus in eutherian pregnancies. in order to understand the evolution of the placenta and provide further understanding of placenta biology, we sequenced the transcriptome of a term placenta of an african elephant (loxodonta africana) and compared these data with rna sequence and microarray data from other eutherian placentas including human, mouse, and cow. we characterized the composition of 55,910 expressed sequence tag (i.e., cdna) contigs usin ...201222546564
eradication of elephant ear mites (loxoanoetus bassoni) in two african elephants (loxodonta africana).elephant ear mites, not previously described in north america, were eradicated in two african elephants (loxodonta africana) after six otic instillations of ivermectin at 2-wk intervals. the microscopic examination of a clear, mucoid discharge collected from the external ear canals of two wild-born african elephants housed in a new york state zoo for 25 yr revealed live mites (loxoaneotus bassoni). the cytologic examination demonstrated no evidence of inflammation or infection. both elephants we ...201222448521
strangulating intestinal obstructions in four captive elephants (elephas maximus and loxodonta africana).three captive-born (5-day-old, 8-day-old, and 4-yr-old) asian elephants (elephas maximus) and one captive-born 22-yr-old african elephant (loxodonta africana) from three private elephant facilities and one zoo in the united states presented with depression, anorexia, and tachycardia as well as gastrointestinal signs of disease including abdominal distention, decreased borborygmi, tenesmus, hematochezia, or diarrhea. all elephants showed some evidence of discomfort including agitation, vocalizati ...201222448519
real-time pcr detection and quantification of elephantid dna: species identification for highly processed samples associated with the ivory trade.the ivory industry is the single most serious threat to global elephant populations. a highly sensitive, species-specific real-time pcr assay has been developed to detect and quantify african elephant (loxodonta africana), asian elephant (elephas maximus) and woolly mammoth (mammuthus primigenius) mitochondrial dna from highly processed samples involved in the international ivory trade. this assay is especially useful for highly processed samples where there are no distinguishing morphological f ...201222257967
putting the elephant back in the herd: elephant relative quantity judgments match those of other species.the ability to discriminate between quantities has been observed in many species. typically, when an animal is given a choice between two sets of food, accurate performance (i.e., choosing the larger amount) decreases as the ratio between two quantities increases. a recent study reported that elephants did not exhibit ratio effects, suggesting that elephants may process quantitative information in a qualitatively different way from all other nonhuman species that have been tested (irie-sugimoto ...201222692435
chemical signals of elephant musth: temporal aspects of microbially-mediated modifications.mature male african (loxodonta africana) and asian (elephas maximus) elephants exhibit periodic episodes of musth, a state in which serum androgens are elevated, food intake typically decreases, aggressiveness often increases, and breeding success is enhanced. urine is a common source of chemical signals in a variety of mammals. elephants in musth dribble urine almost continuously for lengthy periods, suggesting that the chemicals in their urine may reveal their physiological condition to conspe ...201222246519
the identification of elephant ivory evidences of illegal trade with mitochondrial cytochrome b gene and hypervariable d-loop region.dna analysis of elephant ivory of illegal trade was handled in this work. the speciation and geographical origin of nine specimens of elephant ivory were requested by the police. without national authorization, the suspect had purchased processed ivory seals from january to may, 2011 by internet transactions from a site in a neighboring country. the dna of decalcified ivory evidences was isolated with qiagen micro kit. the total 844-904 base pair sized sequences of mitochondrial cytochrome b and ...201223472798
non-invasive assessment of the reproductive cycle in free-ranging female african elephants (loxodonta africana) treated with a gonadotropin-releasing hormone (gnrh) vaccine for inducing anoestrus.in southern africa, various options to manage elephant populations are being considered. immunocontraception is considered to be the most ethically acceptable and logistically feasible method for control of smaller and confined populations. in this regard, the use of gonadotropin-releasing hormone (gnrh) vaccine has not been investigated in female elephants, although it has been reported to be safe and effective in several domestic and wildlife species. the aims of this study were to monitor the ...201222921012
development of the germinal ridge and ovary in the african elephant (loxodonta africana).the follicular reserve and its ontogeny in the elephant are of interest because elephants have the longest reproductive life of all land-based mammals. they also have the longest recorded pregnancy, which allows a protracted view of the series of significant events involved in the development of the embryonic and fetal gonads. the large elephant population of zimbabwe provided the opportunity to collect conceptuses from elephants culled for management reasons and hunted professionally. five embr ...201222991581
wild female african elephants (loxodonta africana) exhibit personality traits of leadership and social integration.animal personalities have been demonstrated for almost 200 species, with stable dimensions of responses (aggressive to fearful; shy to bold) across contexts and with a heritable basis to these traits. as a long-lived and highly social species, elephants (loxodonta africana) were expected to demonstrate complex dimensions to individual characteristics or personalities, which would be obvious to human observers and validated by behavioral observations. we used principal-components analysis of rati ...201222905995
enriching the captive elephant population genetic pool through artificial insemination with frozen-thawed semen collected in the wild.the first successful ai in an elephant was reported in 1998, using fresh semen. since then almost 40 calves have been produced through ai in both asian and african elephants worldwide. following these successes, with the objective of enriching the captive population with genetic material from the wild, we evaluated the possibility of using frozen-thawed semen collected from wild bulls for ai in captivity. semen, collected from a 36-yr-old wild african savanna elephant (loxodonta africana) in sou ...201222898009
growth and development of the ovary and small follicle pool from mid fetal life to pre-puberty in the african elephant (loxodonta africana).follicle numbers and developing ovarian morphology, particularly with reference to the presence of interstitial tissue, are intimately linked within the ovary of the african elephant during the period spanning mid-gestation to puberty. these have not been previously quantified in any studies. the collection of 7 sets of elephant fetal ovaries between 11.2 and 20.2 months of gestation, and 29 pairs of prepubertal calf ovaries between 2 months and 9 years of age during routine management off-takes ...201222824067
effects of daily management changes on behavioral patterns of a solitary female african elephant (loxodonta africana) in a zoo.this study investigated the effects of changes in daily management on behavior of a solitary female elephant in a zoo. the activity budget and space utilization of the subject and the management changes were recorded for 1 year after the conspecific male died. the observation days could be categorized into five clusters (c1-c5) by the characteristic behavioral pattern of each day. c1 had the highest percentage of resting of all clusters, and was observed after the loss of the conspecific and the ...201222776795
genetic identification of five strongyle nematode parasites in wild african elephants (loxodonta africana).african savannah elephants (loxodonta africana) are an ecologically and economically important species in many african habitats. however, despite the importance of elephants, research on their parasites is limited, especially in wild populations. currently, we lack genetic tools to identify elephant parasites. we present genetic markers from ribosomal dna (rdna) and mitochondrial dna (mtdna) to identify five elephant-specific nematode parasites in the family strongylidae: murshidia linstowi, mur ...201222740536
luteal maintenance of pregnancy in the african elephant (loxodonta africana).the ovaries of eight african elephant foetuses and their mothers between 2 and 22 months of gestation, and those of two cycling and two lactating elephants, were examined grossly, histologically and immunocytochemically, with emphasis on the development and regression of accessory corpora lutea (cl) of pregnancy and the steroidogenic capacities of the accessory cl and the foetal ovaries. the results supported recent findings that the accessory cl form as a result of luteinisation, with and witho ...201222457432
dilated ureters, renal dysplasia, and chronic renal failure in an african elephant (loxodonta africana).an ultrasonographic reproductive health examination of a 26-yr-old female african elephant (loxodonta africana) revealed bilateral ureteral wall thickening and dilatation. on ultrasonographic examination, the bladder and both ureters were normal near the trigone; however, the cranial-most aspect of each ureter was dilated and thickened for a length of 30-50 cm. the same month, elevated blood creatinine (3.0 mg/dl), and urine protein-creatinine ratio (4.0) were observed. chronic renal failure was ...201222448523
fecal 20-oxo-pregnane concentrations in free-ranging african elephants (loxodonta africana) treated with porcine zona pellucida vaccine.because of overpopulation of african elephants in south africa and the consequent threat to biodiversity, the need for a method of population control has become evident. in this regard, the potential use of the porcine zona pellucida (pzp) vaccine as an effective means for population control is explored. while potential effects of pzp treatment on social behavior of african elephants have been investigated, no examination of the influence of pzp vaccination on the endocrine correlates in treated ...201222444560
stable isotope series from elephant ivory reveal lifetime histories of a true dietary generalist.longitudinal studies have revealed how variation in resource use within consumer populations can impact their dynamics and functional significance in communities. here, we investigate multi-decadal diet variations within individuals of a keystone megaherbivore species, the african elephant (loxodonta africana), using serial stable isotope analysis of tusks from the kruger national park, south africa. these records, representing the longest continuous diet histories documented for any extant spec ...201222337695
skeletal development in the african elephant and ossification timing in placental mammals.we provide here unique data on elephant skeletal ontogeny. we focus on the sequence of cranial and post-cranial ossification events during growth in the african elephant (loxodonta africana). previous analyses on ossification sequences in mammals have focused on monotremes, marsupials, boreoeutherian and xenarthran placentals. here, we add data on ossification sequences in an afrotherian. we use two different methods to quantify sequence heterochrony: the sequence method and event-paring/parsimo ...201222298853
quantitative analysis of neocortical gyrencephaly in african elephants (loxodonta africana) and six species of cetaceans: comparison with other mammals.this study provides quantitative data on the extent of gyrencephaly in the large-brained african elephant and several species of cetaceans (from smaller to larger brained) in comparison with other mammals. across three mammalian orders (primates, carnivores, and artiodactyls), the species with the larger brains are more gyrencephalic with each order, exhibiting a specific negative allometry. the african elephant, with a 5-kg brain, has a gyrencephalic index (gi) of 3.89, which, though highly gyr ...201222237903
elephants have relatively the largest cerebellum size of mammals.the current study used mr imaging to determine the volume of the cerebellum and its component parts in the brain of three adult male african elephants (loxodonta africana) and compared this with published data from asian elephants and other mammalian species including odontocete cetaceans, primates, chiropterans, insectivores, carnivores, and artiodactyls. the cerebellum of the adult elephant has a volume of ∼925 ml (average of both african and asian species). allometric analysis indicates that ...201222282440
influence of dominance status on adrenal activity and ovarian cyclicity status in captive african elephants.the north american african (loxodonta africana) elephant population is not self-sustaining, in part because of a high rate of abnormal ovarian activity. about 12% of adult females exhibit irregular cycles and 31% do not cycle at all. our earlier work revealed a relationship between dominance status and ovarian acyclicity, with dominant females being more likely to not cycle normally. one theory is that dominant females may be expending more energy to maintaining peace within the captive herd tha ...201320033989
the social and ecological integration of captive-raised adolescent male african elephants (loxodonta africana) into a wild population.a rapid rise in the number of captive african elephants (loxodonta africana) used in the tourism industry in southern africa and orphaned elephants in human care has led to concerns about their long-term management, particularly males. one solution is to release them into the wild at adolescence, when young males naturally leave their herd. however, this raises significant welfare concerns: little is known about how well released elephants integrate into wild populations and whether they pose a ...201323437076
comparative demography of an at-risk african elephant population.knowledge of population processes across various ecological and management settings offers important insights for species conservation and life history. in regard to its ecological role, charisma and threats from human impacts, african elephants are of high conservation concern and, as a result, are the focus of numerous studies across various contexts. here, demographic data from an individually based study of 934 african elephants in samburu, kenya were summarized, providing detailed inspectio ...201323341984
freezing african elephant semen as a new population management tool.the captive elephant population is not self-sustaining and with a limited number of breeding bulls, its genetic diversity is in decline. one way to overcome this is to import young and healthy animals from the wild. we introduce here a more sustainable alternative method - importation of semen from wild bulls without removing them from their natural habitat. due to the logistics involved, the only practical option would be to transport cryopreserved sperm. despite some early reports on african e ...201323483917
laparoscopic vasectomy in african savannah elephant (loxodonta africana); surgical technique and results.several small, enclosed reserves in southern africa are experiencing significant elephant population growth, which has resulted in associated environmental damage and changes in biodiversity. although several techniques exist to control elephant populations, e.g., culling, relocation, and immunocontraception, the technique of laparoscopic vasectomy of free-ranging bull elephants was investigated. bilateral vasectomies were performed in 45 elephants. of these elephants, one died within 24 hr of r ...201324437080
characterization of a novel polyomavirus isolated from a fibroma on the trunk of an african elephant (loxodonta africana).viruses of the family polyomaviridae infect a wide variety of avian and mammalian hosts with a broad spectrum of outcomes including asymptomatic infection, acute systemic disease, and tumor induction. in this study a novel polyomavirus, the african elephant polyomavirus 1 (aelpyv-1) found in a protruding hyperplastic fibrous lesion on the trunk of an african elephant (loxodonta africana) was characterized. the aelpyv-1 genome is 5722 bp in size and is one of the largest polyomaviruses characteri ...201324205012
effects of social disruption in elephants persist decades after culling.multi-level fission-fusion societies, characteristic of a number of large brained mammal species including some primates, cetaceans and elephants, are among the most complex and cognitively demanding animal social systems. many free-ranging populations of these highly social mammals already face severe human disturbance, which is set to accelerate with projected anthropogenic environmental change. despite this, our understanding of how such disruption affects core aspects of social functioning i ...201324152378
complex vibratory patterns in an elephant larynx.elephants' low-frequency vocalizations are produced by flow-induced self-sustaining oscillations of laryngeal tissue. to date, little is known in detail about the vibratory phenomena in the elephant larynx. here, we provide a first descriptive report of the complex oscillatory features found in the excised larynx of a 25 year old female african elephant (loxodonta africana), the largest animal sound generator ever studied experimentally. sound production was documented with high-speed video, aco ...201324133151
the progression of small-follicle reserves in the ovaries of wild african elephants (loxodonta africana) from puberty to reproductive senescence.this study aimed to determine whether the follicle reserve in the ovary of the african elephant declines progressively after puberty and whether its depletion constrains the fertility of older females. elephant ovaries were fixed in 4% neutral buffered formalin and small-follicle counts made using stereological protocols. excepting a slight rise in small-follicle numbers between 16 and 25 years of age, there was a trend for follicle numbers to fall from puberty to 70 years. reproductive status d ...201324112390
architectural organization of the african elephant diencephalon and brainstem.the current study examined the organization of the diencephalon and brainstem of the african elephant (loxodonta africana) - a region of the elephant brain that has not been examined for at least 50 years. the current description, employing material amenable for use with modern neuroanatomical methods, shows that, for the most part, the elephant diencephalon and brainstem are what could be considered typically mammalian, with subtle differences in proportions and topology. the variations from th ...201324021932
conservation outside protected areas and the effect of human-dominated landscapes on stress hormones in savannah elephants.biodiversity conservation strategies are increasingly focused on regions outside national protected areas, where animals face numerous anthropogenic threats and must coexist with human settlements, livestock, and agriculture. the effects of these potential threats are not always clear, but they could have profound implications for population viability. we used savannah elephants (loxodonta africana) as a case study to assess the physiological stress associated with living in a human-livestock-do ...201323692020
hyperprolactinemia is not associated with hyperestrogenism in noncycling african elephants (loxodonta africana).african elephants in us zoos are not reproducing at replacement levels. this is in part due to physiological problems, one of which is abnormal ovarian cyclicity that has been linked to increased prolactin secretion (hyperprolactinemia). a relationship between increased estrogen production (hyperestrogenism) and hyperprolactinemia has been found in other species. therefore, the objective of this study was to determine if elevated prolactin was associated with increased estrogen concentrations in ...201323623777
african elephants adjust speed in response to surface-water constraint on foraging during the dry-season.most organisms need to acquire various resources to survive and reproduce. individuals should adjust their behavior to make optimal use of the landscape and limit the costs of trade-offs emerging from the use of these resources. here we study how african elephants loxodonta africana travel to foraging places between regular visits to waterholes. elephant herds were tracked using gps collars during two consecutive dry seasons in hwange national park, zimbabwe. we segmented each individual movemen ...201323554989
enduring consequences of early experiences: 40 year effects on survival and success among african elephants (loxodonta africana).growth from conception to reproductive onset in african elephants (loxodonta africana) provides insights into phenotypic plasticity, individual adaptive plastic responses and facultative maternal investment. using growth for 867 and life histories for 2652 elephants over 40 years, we demonstrate that maternal inexperience plus drought in early life result in reduced growth rates for sons and higher mortality for both sexes. slow growth during early lactation was associated with smaller adult siz ...201323407501
unmanned aerial survey of elephants.the use of a uas (unmanned aircraft system) was tested to survey large mammals in the nazinga game ranch in the south of burkina faso. the gatewing ×100™ equipped with a ricoh gr iii camera was used to test animal reaction as the uas passed, and visibility on the images. no reaction was recorded as the uas passed at a height of 100 m. observations, made on a set of more than 7000 images, revealed that only elephants (loxodonta africana) were easily visible while medium and small sized mammals we ...201323405088
quantifying past and present connectivity illuminates a rapidly changing landscape for the african elephant.there is widespread concern about impacts of land-use change on connectivity among animal and plant populations, but those impacts are difficult to quantify. moreover, lack of knowledge regarding ecosystems before fragmentation may obscure appropriate conservation targets. we use occurrence and population genetic data to contrast connectivity for a long-lived mega-herbivore over historical and contemporary time frames. we test whether (i) historical gene flow is predicted by persistent landscape ...201323398457
ovarian cycle activity varies with respect to age and social status in free-ranging elephants in addo elephant national park, south africa.free-ranging african elephants live in a fission-fusion society, at the centre of which is the matriarch. matriarchs are generally older females that guide their families to resources and co-ordinate group defense. while much is known about elephant society, knowledge is generally lacking about how age affects the physiology of wild elephants. investigation of the ovarian activity of free-ranging elephants could provide insight into the reproductive ageing process, with implications for populati ...201327293609
the release of a captive-raised female african elephant (loxodonta africana) in the okavango delta, botswana.wild female elephants live in close-knit matrilineal groups and housing captive elephants in artificial social groupings can cause significant welfare issues for individuals not accepted by other group members. we document the release of a captive-raised female elephant used in the safari industry because of welfare and management problems. she was fitted with a satellite collar, and spatial and behavioural data were collected over a 17-month period to quantify her interactions with the wild pop ...201326487408
using diel movement behavior to infer foraging strategies related to ecological and social factors in elephants.adaptive movement behaviors allow individuals to respond to fluctuations in resource quality and distribution in order to maintain fitness. classically, studies of the interaction between ecological conditions and movement behavior have focused on such metrics as travel distance, velocity, home range size or patch occupancy time as the salient metrics of behavior. driven by the emergence of very regular high frequency data, more recently the importance of interpreting the autocorrelation structu ...201325709826
social learning in captive african elephants (loxodonta africana africana).social learning is a more efficient method of information acquisition and application than trial and error learning and is prevalent across a variety of animal taxa. social learning is assumed to be important for elephants, but evidence in support of that claim is mostly anecdotal. using a herd of six adult female african bush elephants (loxodonta africana africana) at the san diego zoo's safari park, we evaluated whether viewing a conspecific's interactions facilitated learning of a novel task. ...201323238635
shift in black rhinoceros diet in the presence of elephant: evidence for competition?in african large herbivore assemblages, megaherbivores dominate the biomass and utilise the greatest share of available resources. consequently, they are considered a separate trophic guild that structures the food niches of coexisting large herbivores. however, there exists little empirical evidence on how food resources are shared within this guild, and none for direct competition for food between megaherbivores. using the histological analysis of faeces, we explore this phenomenon for african ...201323874997
effect of calcium and cholecalciferol supplementation on several parameters of calcium status in plasma and urine of captive asian (elephas maximus) and african elephants (loxodonta africana).the aim of the current study was to assess the effect of oral calcium and cholecalciferol supplementation on several parameters of calcium status in plasma and urine of captive asian (elephas maximus; n=10) and african elephants (loxodonta africana; n=6) and to detect potential species differences. calcium and cholecalciferol supplementation were investigated in a feeding trial using a crossover design consisting of five periods of 28 days each in summer. from days 28-56 (period 2), elephants we ...201324063079
climate influences thermal balance and water use in african and asian elephants: physiology can predict drivers of elephant distribution.elephant movement patterns in relation to surface water demonstrate that they are a water-dependent species. thus, there has been interest in using surface water management to mitigate problems associated with localized elephant overabundance. however, the physiological mechanisms underlying the elephant's water dependence remain unclear. although thermoregulation is likely an important driver, the relationship between thermoregulation, water use and climate has not been quantified. we measured ...201323842629
prenatal passive transfer of maternal immunity in asian elephants (elephas maximus).asian (elephas maximus) and african (loxodonta africana) elephants exhibit characteristics of endotheliochorial placentation, which is common in carnivore species and is associated with modest maternal to fetal transplacental antibody transfer. however, it remains unknown whether the bulk of passive immune transfer in elephants is achieved prenatally or postnatally through ingestion of colostrum, as has been documented for horses, a species whose medical knowledgebase is often extrapolated for e ...201323582266
fatal herpesvirus hemorrhagic disease in wild and orphan asian elephants in southern india.up to 65% of deaths of young asian elephants (elephas maximus) between 3 mo and 15 yr of age in europe and north america over the past 20 yr have been attributed to hemorrhagic disease associated with a novel dna virus called elephant endotheliotropic herpesvirus (eehv). to evaluate the potential role of eehv in suspected cases of a similar lethal acute hemorrhagic disease occurring in southern india, we studied pathologic tissue samples collected from field necropsies. nine cases among both orp ...201323568914
sperm dna fragmentation and morphological degeneration in chilled elephant (elephas maximus and loxodonta africana) semen collected by transrectal massage.ejaculates from nine asian and two african elephants were analysed to gain a further understanding of mechanisms underlying variable semen quality after transrectal massage. semen analysis was performed after collection (0 h; subjective motility parameters only) and after 24 h of chilled storage at 10 °c (24 h; all ejaculate and sperm characteristics). ejaculates with ≤50% total motility (tm) at 24 h, which represented >90% of collection attempts, contained a sperm population with a high degree ...201323536498
conservation challenge: human-herbivore conflict in chebera churchura national park, ethiopia.an investigation on human-herbivore conflict was carried out in ccnp between 2011 and 2012 in seven randomly selected villages (chebera, serri, yora, shita, delba, chuchra, chewda) around the park. a total of 312 household samples were identified for interview. group discussion and field observation were also carried out. among the respondents, the majority (83.9%) faced crop damage. african elephant (loxodonta africana), hippopotamus (hippopotamus amphibious), african buffalo (syncerus caffer), ...201324506044
lack of spatial and behavioral responses to immunocontraception application in african elephants (loxodonta africana).opinions are divided as to whether human intervention to control elephant (loxodonta africana) population growth is desirable, partly because of elephant welfare concerns. female contraception through immunization with porcine zona pellucida (pzp) proteins is viable. the effects of sustained use and application of the pzp vaccine on elephant behavioral and spatial responses were examined by evaluating herd ranging, fission-fusion dynamics, association patterns, and reproductive and sexual behavi ...201324437086
prevalence of antibodies to alphaviruses and flaviviruses in free-ranging game animals and nonhuman primates in the greater congo basin.vector-borne and zoonotic pathogens have comprised a significant proportion of the emerging infectious diseases in humans in recent decades. the role of many wildlife species as reservoirs for arthropod-borne viral pathogens is poorly understood. we investigated the exposure history of various african wildlife species from the congo basin to mosquito-borne flaviviruses and alphaviruses by testing archived serum samples. sera from 24 african forest buffalo (syncerus caffer nanus), 34 african elep ...201323778608
molecular characterization of cryptosporidium species at the wildlife/livestock interface of the kruger national park, south africa.molecular characterization of cryptosporidium spp. was done on isolates from african elephant (loxodonta africana), african buffalo (syncerus caffer), impala (aepyceros melampus) and native domestic calves collected during may and june 2008 at the wildlife/livestock interface of the kruger national park (knp), south africa. a polymerase chain reaction (pcr) restriction fragment length polymorphism (rflp) analysis of the 18s rrna gene was used in feces from 51 calves (3-12 months of age), 71 buff ...201322975725
effects of host demography, season and rainfall on the prevalence and parasitic load of gastrointestinal parasites of free-living elephants (loxodonta africana) of the chad basin national park, nigeria.the effects of host demography, rainfall and season on the prevalence and parasitic load of gastrointestinal parasites of african elephants (loxodonta africana) of the chad basin national park were determined for the first time. out of the 274 elephants examined, 36.86% were infected. of the 178 males examined, 35.96% harboured strongyloides, coccidia and strongyles with worm burdens of 75.6 +/- 0.3, 125.2 +/- 1.4 and 420.2 +/- 0.1, respectively. among the males, the larvae of strongyloides papi ...201324506015
retrospective genetic characterisation of encephalomyocarditis viruses from african elephant and swine recovers two distinct lineages in south africa.encephalomyocarditis virus (emcv) outbreaks are rare in southern africa. only two have been reported to date from south africa, both coinciding with rodent irruptions. the first outbreak manifested as acute myocarditis in pigs in 1979, whilst the second, occurring from 1993 to 1994, was linked to the deaths of 64 free-ranging adult african elephants (loxodonta africana). the p1 genome region, inclusive of the flanking leader (l) and 2a genes, of three south african isolates, one from swine and t ...201323021643
frequent and seasonally variable sublethal anthrax infections are accompanied by short-lived immunity in an endemic system.few studies have examined host-pathogen interactions in wildlife from an immunological perspective, particularly in the context of seasonal and longitudinal dynamics. in addition, though most ecological immunology studies employ serological antibody assays, endpoint titre determination is usually based on subjective criteria and needs to be made more objective. despite the fact that anthrax is an ancient and emerging zoonotic infectious disease found world-wide, its natural ecology is not well u ...201424499424
african elephant alarm calls distinguish between threats from humans and bees.the samburu pastoralists of northern kenya co-exist with african elephants, loxodonta africana, and compete over resources such as watering holes. audio playback experiments demonstrate that african elephants produce alarm calls in response to the voices of samburu tribesmen. when exposed to adult male samburu voices, listening elephants exhibited vigilance behavior, flight behavior, and produced vocalizations (rumbles, roars and trumpets). rumble vocalizations were most common and were characte ...201424586753
diurnal and nocturnal activity budgets of zoo elephants in an outdoor facility.the present study examined the activity budgets of 15 african elephants (1 bull, 6 cows, 2 male juveniles, 2 female juveniles, and 4 male calves) living at the san diego zoo safari park during the summers of 2010 and 2011. onsite behavioral data (n = 600 hr) were collected for approximately 12 weeks from 0400 to 0830 and 1100 to 2400 during the 2010 and 2011 summer season. foraging was the most common behavior state during the day followed by resting, and walking. during the evening hours, the e ...201425113850
assessment of ovarian cycles in the african elephant (loxodonta africana) by measurement of salivary progesterone metabolites.monitoring ovarian cycles through hormonal analysis is important in order to improve breeding management of captive elephants, and non-invasive collection techniques are particularly interesting for this purpose. however, there are some practical difficulties in collecting proper samples, and easier and more practical methods may be an advantage for some institutions and/or some animals. this study describes the development and validation of an enzymeimmunoassay (eia) for progestins in salivary ...201424610639
supression of testicular function in a male asian elephant (elephas maximus) treated with gonadotropin-releasing hormone vaccines.the ability to control testosterone concentrations and sperm production is of great interest in both asian (elephas maximus) and african (loxodonta africana) elephants. gnrh vaccination may pose an alternative to surgical castration. this is a case report of a male asian elephant treated with two commercial gnrh vaccines (equity and improvac). beginning at the age of 7 yr, the male was vaccinated monthly for 6 consecutive months, then every 6 mo and, finally, every 12 to 24 mo over a period of 6 ...201425314829
vocal learning in elephants: neural bases and adaptive context.in the last decade clear evidence has accumulated that elephants are capable of vocal production learning. examples of vocal imitation are documented in african (loxodonta africana) and asian (elephas maximus) elephants, but little is known about the function of vocal learning within the natural communication systems of either species. we are also just starting to identify the neural basis of elephant vocalizations. the african elephant diencephalon and brainstem possess specializations related ...201425062469
low coverage sequencing of two asian elephant (elephas maximus) genomes.there are three species of elephant that exist, the asian elephant (elephas maximus) and two species of african elephant (loxodonta africana and loxodonta cyclotis). the populations of all three species are dwindling, and are under threat due to factors, such as habitat destruction and ivory hunting. the species differ in many respects, including in their morphology and response to disease. the availability of elephant genome sequence data from all three elephant species will complement studies ...201425053995
fine-scale genetic structure and cryptic associations reveal evidence of kin-based sociality in the african forest elephant.spatial patterns of relatedness within animal populations are important in the evolution of mating and social systems, and have the potential to reveal information on species that are difficult to observe in the wild. this study examines the fine-scale genetic structure and connectivity of groups within african forest elephants, loxodonta cyclotis, which are often difficult to observe due to forest habitat. we tested the hypothesis that genetic similarity will decline with increasing geographic ...201424505381
detection of elephant endotheliotropic herpesvirus infection among healthy asian elephants (elephas maximus) in south india.elephant endotheliotropic herpesviruses (eehvs) can cause fatal hemorrhagic disease in asian (elephas maximus) and african (loxodonta africana) elephants. of the seven known eehv species, eehv1 is recognized as the most common cause of hemorrhagic disease among asian elephants in human care worldwide. recent data collected from ex situ asian elephants located in multiple north american and european institutions suggest that subclinical eehv1 infection is common in this population of elephants. a ...201424484479
molecular characterization of adipose tissue in the african elephant (loxodonta africana).adipose tissue (at) is a dynamic and flexible organ with regulatory roles in physiological functions including metabolism, reproduction and inflammation; secreted adipokines, including leptin, and fatty acids facilitate many of these roles. the african elephant (loxodonta africana) is experiencing serious challenges to optimal reproduction in captivity. the physiological and molecular basis of this impaired fertility remains unknown. at production of leptin is a crucial molecular link between nu ...201424633017
understanding tourists' preference for mammal species in private protected areas: is there a case for extralimital species for ecotourism?private protected areas (ppas) often use wildlife-based ecotourism as their primary means of generating business. achieving tourist satisfaction has become a strong driving goal in the management of many ppas, often at the expense of biodiversity. many extralimitral species, those which historically did not occur in an area, are stocked in ppas with the intention of increasing ecotourism attractions. even though the ecological and economic costs of stocking these species are high, the social ben ...201424505426
interpretation of human pointing by african elephants: generalisation and rationality.factors influencing the abilities of different animals to use cooperative social cues from humans are still unclear, in spite of long-standing interest in the topic. one of the few species that have been found successful at using human pointing is the african elephant (loxodonta africana); despite few opportunities for learning about pointing, elephants follow a pointing gesture in an object-choice task, even when the pointing signal and experimenter's body position are in conflict, and when the ...201424942107
elephants can determine ethnicity, gender, and age from acoustic cues in human voices.animals can accrue direct fitness benefits by accurately classifying predatory threat according to the species of predator and the magnitude of risk associated with an encounter. human predators present a particularly interesting cognitive challenge, as it is typically the case that different human subgroups pose radically different levels of danger to animals living around them. although a number of prey species have proved able to discriminate between certain human categories on the basis of v ...201424616492
detusking fence-breaker elephants as an approach in human-elephant conflict mitigation.human-elephant conflict (hec) is a recurring problem that appears wherever the range of elephants and humans overlap. different methods including the use of electric fences are used worldwide to mitigate this conflict. nonetheless, elephants learn quickly that their tusks do not conduct electricity and use them to break down fences (fence-breakers).201424614538
organization and chemical neuroanatomy of the african elephant (loxodonta africana) hippocampus.elephants are thought to possess excellent long-term spatial-temporal and social memory, both memory types being at least in part hippocampus dependent. although the hippocampus has been extensively studied in common laboratory mammalian species and humans, much less is known about comparative hippocampal neuroanatomy, and specifically that of the elephant. moreover, the data available regarding hippocampal size of the elephant are inconsistent. the aim of the current study was to re-examine hip ...201423728481
use of tolazoline as an antagonist to xylazine-ketamine-induced immobilization in african elephants.a group of 15 african elephants (loxodonta africana) were immobilized with a combination of xylazine (0.2 mg/kg of body weight, im) and ketamine (1 to 1.5 mg/kg of body weight, im). ten of the african elephants were allowed to remain recumbent for 30 minutes and the remaining 5 elephants, for 45 minutes before they were given tolazoline (0.5 mg/kg of body weight, iv). for the group of 15, the mean induction time (the time required from injection of the xylazine-ketamine combination until onset o ...20143963578
exploratory rigid laparoscopy in an african elephant (loxodonta africana).in march 2009, a 25-yr-old captive female african elephant (loxodonta africana) underwent an exploratory laparoscopy after several weeks of diarrhea, submandibular and ventral edema, and swelling on medial and lateral aspects of all feet. although there have been recent advances in laparoscopic vasectomies in free-ranging african elephants in south africa utilizing specially designed rigid laparoscopes and insufflation devices, this was the first attempt at using these same techniques for an exp ...201425632688
age group estimation in free-ranging african elephants based on acoustic cues of low-frequency rumbles.animal vocal signals are increasingly used to monitor wildlife populations and to obtain estimates of species occurrence and abundance. in the future, acoustic monitoring should function not only to detect animals, but also to extract detailed information about populations by discriminating sexes, age groups, social or kin groups, and potentially individuals. here we show that it is possible to estimate age groups of african elephants (loxodonta africana) based on acoustic parameters extracted f ...201425821348
recurrence of hyperprolactinemia and continuation of ovarian acyclicity in captive african elephants (loxodonta africana) treated with cabergoline.hyperprolactinemia is associated with reproductive acyclicity in zoo african elephants (loxodonta africana) and may contribute to the non-self-sustainability of the captive population in north america. it is a common cause of infertility in women and other mammals and can be treated with the dopamine agonist cabergoline. the objectives of this study were to assess prolactin responses to cabergoline treatment in hyperprolactinemic, acyclic african elephants and to determine the subsequent impact ...201425314824
response of african elephants (loxodonta africana) to seasonal changes in rainfall.the factors that trigger sudden, seasonal movements of elephants are uncertain. we hypothesized that savannah elephant movements at the end of the dry season may be a response to their detection of distant thunderstorms. nine elephants carrying global positioning system (gps) receivers were tracked over seven years in the extremely dry and rugged region of northwestern namibia. the transition date from dry to wet season conditions was determined annually from surface- and satellite-derived rainf ...201425299514
data-driven discovery of the spatial scales of habitat choice by elephants.setting conservation goals and management objectives relies on understanding animal habitat preferences. models that predict preferences combine location data from tracked animals with environmental information, usually at a spatial resolution determined by the available data. this resolution may be biologically irrelevant for the species in question. individuals likely integrate environmental characteristics over varying distances when evaluating their surroundings; we call this the scale of se ...201425177532
elevated elephant density does not improve ecotourism opportunities: convergence in social and ecological objectives.in order to sustainably conserve biodiversity, many protected areas, particularly private protected areas, must find means of self-financing. ecotourism is increasingly seen as a mechanism to achieve such financial sustainability. however, there is concern that ecotourism operations are driven to achieve successful game-viewing, influencing the management of charismatic species. an abundance of such species, including the african elephant (loxodonta africana), has been stocked in protected areas ...201425154086
african elephants (loxodonta africana) recognize visual attention from face and body orientation.how do animals determine when others are able and disposed to receive their communicative signals? in particular, it is futile to make a silent gesture when the intended audience cannot see it. some non-human primates use the head and body orientation of their audience to infer visual attentiveness when signalling, but whether species relying less on visual information use such cues when producing visual signals is unknown. here, we test whether african elephants (loxodonta africana) are sensiti ...201425013015
bilateral ovarian cystadenoma in a geriatric african elephant (loxodonta africana).a 59-yr-old, captive female african elephant (loxodonta africana) died of a cardiovascular collapse. necropsy revealed bilateral replacement of the ovarian tissue by multiple cystic formations of up to 10 cm in diameter. the cysts were thin walled and filled with clear watery fluid. smaller solid masses with an irregular surface projected from the wall of a few of the cysts. histologically, the cystic structures were characterized by a single layer of well-differentiated cuboidal epithelial cell ...201425000708
development of a body condition scoring index for female african elephants validated by ultrasound measurements of subcutaneous fat.obesity-related health and reproductive problems may be contributing to non-sustainability of zoo african elephant (loxodonta africana) populations. however, a major constraint in screening for obesity in elephants is lack of a practical method to accurately assess body fat. body condition scoring (bcs) is the assessment of subcutaneous fat stores based on visual evaluation and provides an immediate appraisal of the degree of obesity of an individual. the objective of this study was to develop a ...201424718304
laparoscopic vasectomy in african elephants (loxodonta africana).to describe a surgical technique for, and outcome after, laparoscopic vasectomy of free-ranging elephants.201424617837
arteriosclerosis in the african elephant: part 2. medial sclerosis.a type of spontaneous arteriosclerosis, described as medial sclerosis and quite distinct from atherosclerosis, was found in the aortas, coronary arteries and aortic branch arteries of free-living elephants (loxodonta africana) in uganda and kenya. the lesions took the form of calcified fibrotic plaques in the inner tunica media. the calcification appeared to commence in the internal elastic lamina and was associated with atrophy of medial smooth muscle fibres and their replacement by fibrous tis ...20141131300
surgical treatment of an umbilical hernia in a free-ranging sub-adult african elephant in samburu national reserve, kenya.a 10-year-old male african elephant (loxodonta africana) at samburu national reserve in northern kenya, weighing approximately 1,600 kg, presented with an umbilical hernia in october 2013. umbilical herniorrhaphy was carried out under field conditions. anesthesia was induced and maintained using etorphine hydrochloride for 3 hours during the surgery. this case report details both the surgical and anesthetic procedure carried out to correct the hernia, and the eventual successful recovery of the ...201530101103
legal ivory trade in a corrupt world and its impact on african elephant populations.illegal hunting of african elephants (loxodonta africana) for ivory is causing rapid declines in their populations. since 2007, illegal ivory trade has more than doubled. african elephants are facing the most serious conservation crisis since 1989, when international trade was banned. one solution proposed is establishment of a controlled legal trade in ivory. high prices for ivory mean that the incentives to obtain large quantities are high, but the quantity of tusks available for trade are bio ...201525103555
all roads lead to rome, even in african savannah elephants--or do they? 201525808893
Displaying items 301 - 400 of 565