Publications
| Title | Abstract | Year Filter | PMID(sorted ascending) Filter |
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| a neuroanatomical comparison of humans and spotted hyena, a natural animal model for common urogenital sinus: clinical reflections on feminizing genitoplasty. | surgical treatment of the common urogenital sinus phallus has been one of the most challenging areas in pediatric urology. to better understand the neuroanatomy of the common urogenital sinus phallus, we evaluated an animal model naturally having this condition, the spotted hyena, crocuta crocuta. we compared the neuroanatomy of male and female humans and spotted hyenas using anatomical, immunohistochemical and 3d reconstruction techniques. we also examined the implications of the pattern of cli ... | 2006 | 16406926 |
| severe streptococcus infection in spotted hyenas in the ngorongoro crater, tanzania. | in a population of spotted hyenas (crocuta crocuta) monitored between 1996 and 2005 in the ngorongoro crater, tanzania, 16 individuals from five of eight social groups displayed clinical signs of an infection, including severe unilateral swelling of the head followed by abscess formation at the mandibular angle, respiratory distress, mild ataxia, and lethargy. two (12.5%) of these 16 individuals died within days of developing signs. clinical signs in hyenas were first noted in 2001, and most cas ... | 2006 | 16460891 |
| molecular systematics of the hyaenidae: relationships of a relictual lineage resolved by a molecular supermatrix. | the four extant species of hyenas (hyaenidae; carnivora) form a morphologically and ecologically heterogeneous group of feliform carnivorans that are remnants of a formerly diverse group of mammalian predators. they include the aardwolf (proteles cristatus), a termite-feeding specialist, and three species with a craniodental morphology adapted to cracking the bones of prey and/or carcasses, the spotted hyena (crocuta crocuta), brown hyena (parahyaena brunnea), and striped hyena (hyaena hyaena). ... | 2006 | 16503281 |
| dominance in vertebrate broods and litters. | drawing on the concepts and theory of dominance in adult vertebrates, this article categorizes the relationships of dominance between infant siblings, identifies the behavioral mechanisms that give rise to those relationships, and proposes a model to explain their evolution. dominance relationships in avian broods can be classified according to the agonistic roles of dominants and subordinates as "aggression-submission," "aggression-resistance," "aggression-aggression," "aggression-avoidance," " ... | 2006 | 16602272 |
| rank-related maternal effects of androgens on behaviour in wild spotted hyaenas. | within any hierarchical society, an individual's social rank can have profound effects on its health and reproductive success, and rank-related variation in these traits is often mediated by variation in endocrine function. maternal effects mediated by prenatal hormone exposure are potentially important for non-genetic inheritance of phenotypic traits related to social rank, and thus for shaping individual variation in behaviour and social structure. here we show that androgen concentrations in ... | 2006 | 16641996 |
| masculinized otoacoustic emissions in female spotted hyenas (crocuta crocuta). | in humans and rhesus monkeys, click-evoked otoacoustic emissions (ceoaes) are stronger in females than in males, and there is considerable circumstantial evidence that this sex difference is attributable to the greater exposure to androgens prenatally in males. because female spotted hyenas are highly androgenized beginning early in prenatal development, we expected an absence of sexual dimorphism in the ceoaes of this species. the ceoaes obtained from 9 male and 7 female spotted hyenas confirme ... | 2006 | 16682033 |
| sex determination in spotted hyena (crocuta crocuta ) by restriction fragment length polymorphism of amplified zfx/zfy loci. | we describe a quick and efficient method of determining the sex of dna samples in the hyena. by choosing primers from sequences that are conserved between the human and bovine zfy and zfx genes, we amplified a 448 bp fragment from 1 male and 2 female hyenas. using comparative sequencing, single base pair polymorphisms between the amplified zfy and zfx were established. restriction fragment length polymorphism (rflp) analysis with psti and taqi confirmed the sequence data and yielded specific ban ... | 1994 | 16727412 |
| distribution of vasopressin in the forebrain of spotted hyenas. | the extreme virilization of the female spotted hyena raises interesting questions with respect to sexual differentiation of the brain and behavior. females are larger and more aggressive than adult, non-natal males and dominate them in social encounters; their external genitalia also are highly masculinized. in many vertebrates, the arginine vasopressin (vp) innervation of the forebrain, particularly that of the lateral septum, is associated with social behaviors such as aggression and dominance ... | 2006 | 16856162 |
| endocrine differentiation of fetal ovaries and testes of the spotted hyena (crocuta crocuta): timing of androgen-independent versus androgen-driven genital development. | female spotted hyenas (crocuta crocuta) have an erectile peniform clitoris and a pseudoscrotum but no external vagina, all established by day 35 of a 110-day gestation. recent studies indicate that these events are androgen-independent, although androgen secretion by fetal ovaries and testis was hypothesized previously to induce phallic development in both sexes. we present the first data relating to the capacity of the ovaries and testes of the spotted hyena to synthesize androgens at different ... | 2006 | 17008476 |
| mammalian sexual differentiation: lessons from the spotted hyena. | female spotted hyenas (crocuta crocuta) are the only female mammals that lack an external vaginal opening. mating and birth take place through a urogenital canal that exits at the tip of a hypertrophied clitoris. this 'masculine' phenotype spurred a search for an alternate source of fetal androgens. although androstenedione from the maternal ovary is readily metabolized to testosterone by the hyena placenta, formation of the penile clitoris and scrotum appear to be largely androgen independent. ... | 2006 | 17010637 |
| structure of the midterm placenta of the spotted hyena, crocuta crocuta, with emphasis on the diverse hemophagous regions. | the hyena placenta is unique among carnivores in being hemochorial. it also has areas of erythrocyte uptake that differ from those seen in more commonly studied carnivores. the availability of timed midterm pregnancies made it possible to examine the organization of the placenta, the distribution of regions of columnar trophoblast and the nature of the heterophagous and hemophagous regions in well-preserved material. the labyrinth of the placenta is orderly arranged with periodic primary villi t ... | 2006 | 17108685 |
| spotted hyenas. | 2006 | 17113370 | |
| placental expression and molecular characterization of aromatase cytochrome p450 in the spotted hyena (crocuta crocuta). | at birth, the external genitalia of female spotted hyenas (crocuta crocuta) are the most masculinized of any known mammal, but are still sexually differentiated. placental aromatase cytochrome p450 (p450arom) is an important route of androgen metabolism protecting human female fetuses from virilization in utero. therefore, placental p450arom expression was examined in spotted hyenas to determine levels during genital differentiation, and to compare molecular characteristics between the hyena and ... | 2007 | 17198727 |
| social intelligence in the spotted hyena (crocuta crocuta). | if the large brains and great intelligence characteristic of primates were favoured by selection pressures associated with life in complex societies, then cognitive abilities and nervous systems with primate-like attributes should have evolved convergently in non-primate mammals living in large, elaborate societies in which social dexterity enhances individual fitness. the societies of spotted hyenas are remarkably like those of cercopithecine primates with respect to size, structure and pattern ... | 2007 | 17289649 |
| erythema multiforme in a spotted hyena (crocuta crocuta). | a 10.5-yr-old male spotted hyena (crocuta crocuta) developed acute, severe erythematous and ulcerative dermatitis of the hindquarters, feet, face, and ears 19 days after receiving a recombinant canary pox vectored canine distemper vaccine. biopsies of the lesions supported a diagnosis of erythema multiforme (em), which is an immune-mediated disorder that can occur days to months after exposure to antigenic stimuli. during the lengthy recovery, esophageal regurgitation and ulceration developed ei ... | 2005 | 17312775 |
| sex and seasonal differences in aggression and steroid secretion in lemur catta: are socially dominant females hormonally 'masculinized'? | female social dominance characterizes many strepsirrhine primates endemic to madagascar, but currently there is no comprehensive explanation for how or why female lemurs routinely dominate males. reconstructing the evolutionary pressures that may have shaped female dominance depends on better understanding the mechanism of inheritance, variation in trait expression, and correlating variables. indeed, relative to males, many female lemurs also display delayed puberty, size monomorphism, and 'masc ... | 2007 | 17382329 |
| transient genital abnormalities in striped hyenas (hyaena hyaena). | the highly masculinized genitalia of female spotted hyenas crocuta crocuta is unique among mammals: crocuta have no external vagina so urination, penile intromission and parturition take place through the clitoris, which mimics a fully erectile male penis. among hyenids, virilization of external female genitalia has previously been observed only in crocuta, so functional explanations of masculinization have focused on aspects of social ecology unique to the species. here we first show that the s ... | 2007 | 17442316 |
| glycosylation at the fetomaternal interface in hemomonochorial placentae from five widely separated species of mammal: is there evidence for convergent evolution? | hemomonochorial placentation occurs in diverse species. we have examined placental glycosylation in five widely separated mammals with this type of placentation--lesser hedgehog tenrec (echinops telfairi), spotted hyena (crocuta crocuta), nine-banded armadillo (dasypus novemcinctus), human (homo sapiens) and guinea pig (cavia porcellus)--in order to assess whether evolutionary convergence to the hemomonochorial state is accompanied by a similar convergence of glycan expression. placentae from 2 ... | 2007 | 17587801 |
| female mate-choice drives the evolution of male-biased dispersal in a social mammal. | dispersal has a significant impact on lifetime reproductive success, and is often more prevalent in one sex than the other. in group-living mammals, dispersal is normally male-biased and in theory this sexual bias could be a response by males to female mate preferences, competition for access to females or resources, or the result of males avoiding inbreeding. there is a lack of studies on social mammals that simultaneously assess these factors and measure the fitness consequences of male disper ... | 2007 | 17700698 |
| non-invasive measurement of fecal estrogens in the spotted hyena (crocuta crocuta). | fecal hormone analysis is a useful tool for frequent, non-invasive sampling of free-living animals. estrogens fluctuate throughout life among reproductive states in female animals, and intensive repetitive sampling can permit accurate assessment of female reproductive condition. this type of repetitive sampling is difficult in large carnivores, including the spotted hyena (crocuta crocuta). patterns of estrogen secretion in captive and free-living hyenas are virtually unknown. here we present va ... | 2008 | 17884046 |
| mammalian body size changes and plio-pleistocene environmental shifts: implications for understanding hominin evolution in eastern and southern africa. | this study examines geographic and temporal variation in three mammalian taxa co-occurring in eastern and southern africa. the selected taxa-the spotted hyena (crocuta crocuta), the plains zebra (equus burchellii), and the impala (aepyceros melampus)--are geographically widespread in modern times and are abundant in eastern and southern african plio-pleistocene fossil sites. craniodental measurements of modern conspecifics from known geographic locations are compared using multivariate statistic ... | 2007 | 17915290 |
| diagnosis and treatment of chronic t-lymphocytic leukemia in a spotted hyena (crocuta crocuta). | physical examination of an asymptomatic 20-yr-old intact female spotted hyena (crocuta crocuta) revealed a midabdominal mass. a complete blood count (cbc) revealed peripheral lymphocytosis. abdominal ultrasonography and laparoscopy confirmed severe splenomegaly. cytologic examination of a bone-marrow core and histologic examination of spleen and liver biopsy samples revealed neoplastic small lymphocytes. immunohistochemical staining of liver and spleen samples with the use of leukocyte-specific ... | 2007 | 17939362 |
| [early sibling aggression in mammals and its hormonal correlates]. | early sibling aggression is a widespread phenomenon in birds. ornithologists distinguish species with "obligate" and "facultative" siblicide. sibling aggression was described in some mammal species: the domestic pig (sus scrofa), the spotted hyena (crocuta crocuta), the eurasian lynx (lynx lynx), and the iberian lynx (l. par-dinus). in all of them, sibling aggression corresponds well with the "facultative" siblicide model in birds. sibling aggression was observed at the age of 36-64 days in both ... | 2007 | 17944114 |
| external genital morphology of the ring-tailed lemur (lemur catta): females are naturally "masculinized". | the extravagance and diversity of external genitalia have been well characterized in male primates; however, much less is known about sex differences or variation in female form. our study represents a departure from traditional investigations of primate reproductive anatomy because we 1) focus on external rather than internal genitalia, 2) measure both male and female structures, and 3) examine a strepsirrhine rather than an anthropoid primate. the subjects for morphological study were 21 repro ... | 2008 | 17972270 |
| characterization of streptococcus equi subsp. ruminatorum isolated from spotted hyenas (crocuta crocuta) and plains zebras (equus burchelli), and identification of a m-like protein (srm) encoding gene. | thirteen strains of streptococcus equi subsp. ruminatorum from free-ranging spotted hyenas (crocuta crocuta) and plains zebras (equus burchelli) in tanzania were characterized by biochemical and molecular-biological methods. although the colony appearance of the s.e. ruminatorum wildlife strains differed from that of the s.e. ruminatorum type strain cect 5772(t), all biochemical reactions of the wildlife strains were similar to those of the type strain. in addition, all wildlife strains produced ... | 2008 | 17997053 |
| predator-prey size relationships in an african large-mammal food web. | 1. size relationships are central in structuring trophic linkages within food webs, leading to suggestions that the dietary niche of smaller carnivores is nested within that of larger species. however, past analyses have not taken into account the differing selection shown by carnivores for specific size ranges of prey, nor the extent to which the greater carcass mass of larger prey outweighs the greater numerical representation of smaller prey species in the predator diet. furthermore, the top- ... | 2008 | 18177336 |
| a hepatozoon species genetically distinct from h. canis infecting spotted hyenas in the serengeti ecosystem, tanzania. | health monitoring of spotted hyenas (crocuta crocuta) in the serengeti ecosystem, tanzania, revealed hepatozoon infection in all of 11 immature individuals examined following death from natural causes. hepatozoon infection was probably an important factor contributing to mortality in two cases that exhibited clinical signs of ataxia, lethargy, ocular discharge, retching, and labored breathing before death. whether hepatozoon infection contributed to six deaths from fire, probable lion predation ... | 2008 | 18263820 |
| pulmonary infection due to mycobacterium goodii in a spotted hyena (crocuta crocuta) from south africa. | we report a case of pyogranulomatous pneumonia due to infection with mycobacterium goodii in an adult female spotted hyena (crocuta crocuta). the lungs of the animal showed consolidated, granulomatous lesions, and they were extensively and severely infiltrated. polymerase chain reaction sequencing of isolated crude lung tissue dna, and boiled lung culture samples, all confirmed that the causative organism was m. goodii, a recently described fast-growing organism closely related to the nonpathoge ... | 2008 | 18263830 |
| do female hyaenas choose mates based on tenure? | in their investigation into whether female mate-choice drives male dispersal, höner et al. argue that female spotted hyaenas (crocuta crocuta) prefer mates whose tenure in the social group is less than the females' age, to avoid paternal incest, and suggest that male dispersal reflects this preference. however, we are not persuaded that females choose mates on the basis of tenure because höner et al. overlook the alternative hypothesis that dispersal status itself is important in female mate-cho ... | 2008 | 18615020 |
| effect of prenatal androgens on click-evoked otoacoustic emissions in male and female sheep (ovis aries). | otoacoustic emissions (oaes) were measured in male and female suffolk sheep (ovis aries). some sheep had been administered androgens or estrogens during prenatal development, some were gonadectomized after birth, and some were allowed to develop normally. as previously reported for spotted hyenas, gonadectomy did not alter the oaes for either sex; accordingly, the untreated/intact and the untreated/gonadectomized animals were pooled to form the control groups. the click-evoked otoacoustic emissi ... | 2009 | 18834887 |
| chemical characterization of milk oligosaccharides of a spotted hyena (crocuta crocuta). | the carnivora include the superfamilies canoidea and feloidea. in species of canoidea other than canidae, the milk contains only traces of lactose and much larger concentrations of oligosaccharides. in this study, the following oligosaccharides were characterized in the milk of a spotted hyena, which is a species of feloidea species: neu5ac(alpha2-3)gal(beta1-4)glc, gal(alpha1-3)[fuc(alpha1-2)]gal(beta1-4)glc, gal(alpha1-3)gal(beta1-4)glc and fuc(alpha1-2)gal(beta1-4)glc. lactose was found to be ... | 2009 | 18840538 |
| parallels between playbacks and pleistocene tar seeps suggest sociality in an extinct sabretooth cat, smilodon. | inferences concerning the lives of extinct animals are difficult to obtain from the fossil record. here we present a novel approach to the study of extinct carnivores, using a comparison between fossil records (n=3324) found in late pleistocene tar seeps at rancho la brea in north america and counts (n=4491) from playback experiments used to estimate carnivore abundance in africa. playbacks and tar seep deposits represent competitive, potentially dangerous encounters where multiple predators are ... | 2009 | 18957359 |
| fecal glucocorticoids reflect socio-ecological and anthropogenic stressors in the lives of wild spotted hyenas. | our aim was to identify natural and anthropogenic influences on the stress physiology of large african carnivores, using wild spotted hyenas (crocuta crocuta) as model animals. with both longitudinal data from a single social group, and cross-sectional data from multiple groups, we used fecal glucocorticoids (fgc) to examine potential stressors among spotted hyenas. longitudinal data from adult members of a group living on the edge of the masai mara national reserve, kenya, revealed that fgc con ... | 2009 | 19056392 |
| a survey of echinococcus species in wild carnivores and livestock in east africa. | we examined 71 faecal samples of carnivores from queen elizabeth national park (qenp), uganda, for eggs of echinococcus species. thirty-nine faecal samples contained taeniid eggs. for species diagnosis, dna was isolated from a total of 1984 individual taeniid eggs. to differentiate eggs of echinococcus felidis from other taeniid taxa (including the closely related echinococcus granulosus sensu stricto), a restriction fragment length polymorphism (rflp)-pcr of the mitochondrial nad1 gene was deve ... | 2009 | 19275902 |
| post-weaning maternal effects and the evolution of female dominance in the spotted hyena. | mammalian societies in which females dominate males are rare, and the factors favouring the evolution of female dominance have yet to be clearly identified. we propose a new hypothesis for the evolution of female dominance and test its predictions with empirical data from the spotted hyena (crocuta crocuta), a well-studied species characterized by female dominance. we suggest that constraints imposed by the development of a feeding apparatus specialized for bone cracking, in combination with the ... | 2009 | 19324728 |
| relaxin concentrations in serum and urine of endangered and crazy mixed-up species. | the human population explosion has pushed many mammalian wildlife species to the brink of extinction. conservationists are increasingly turning to captive breeding as a means of preserving the gene pool. we previously reported that serum immunoactive relaxin provided a reliable means of distinguishing between true and pseudopregnancy in domestic dogs, and this method has since been found to be a reliable indicator of true pregnancy in endangered asian and african elephants and sumatran rhinocero ... | 2009 | 19416182 |
| ontogenetic change in skull morphology and mechanical advantage in the spotted hyena (crocuta crocuta). | weaning represents a challenging transition for young mammals, one particularly difficult for species coping with extreme conditions during feeding. spotted hyenas (crocuta crocuta) experience such extreme conditions imposed by intense feeding competition during which the ability to consume large quantities of food quickly is highly advantageous. as adult spotted hyenas have massive skulls specialized for durophagy and can feed very rapidly, young individuals are likely at a competitive disadvan ... | 2010 | 19862838 |
| what the hyena's laugh tells: sex, age, dominance and individual signature in the giggling call of crocuta crocuta. | among mammals living in social groups, individuals form communication networks where they signal their identity and social status, facilitating social interaction. in spite of its importance for understanding of mammalian societies, the coding of individual-related information in the vocal signals of non-primate mammals has been relatively neglected. the present study focuses on the spotted hyena crocuta crocuta, a social carnivore known for its complex female-dominated society. we investigate i ... | 2010 | 20353550 |
| 'emerging' mycobacteria in south africa. | disease can be caused by various species of the genus mycobacterium. a number of reports, both published and unpublished, of rarely reported mycobacteria have surfaced in south africa in the last few years. some unusual hosts have also been involved, causing concern in some quarters.these include reports on mycobacterium goodii in a spotted hyaena (crocuta crocuta), m. xenopi in a ruffed lemur (varecia variegata), m. intracellulare in wild-caught chacma baboons (papio ursinus), the 'dassie bacil ... | 2009 | 20458859 |
| peptoniphilus methioninivorax sp. nov., a novel gram-positive anaerobic coccus isolated from retail ground beef. | strain nrrl b-23883 was isolated from retail ground beef as part of a study on the genetic diversity of clostridium perfringens. the strain was found to be a strictly anaerobic, gram- positive coccus that was able to utilize peptone as a sole carbon source. subsequent to sequencing the 16s ribosomal rna gene, it was found that the strain was closely related to species within the genera peptoniphilus and anaerosphaera, but it was substantially different from the closest recognized species by near ... | 2010 | 20817843 |
| retrospective analysis of suspected rabies cases reported at bugando referral hospital, mwanza, tanzania. | the aim of this study was to determine the incidence of humans being bitten by rabies-suspected animals, and the victims' adherence to post-exposure prophylaxis (pep) regimen. | 2010 | 20927280 |
| endocrine correlates of pregnancy in the ring-tailed lemur (lemur catta): implications for the masculinization of daughters. | female ring-tailed lemurs (lemur catta) are malagasy primates that are size monomorphic with males, socially dominate males, and exhibit a long, pendulous clitoris, channeled by the urethra. these masculine traits evoke certain attributes of female spotted hyenas (crocuta crocuta) and draw attention to the potential role of androgens in lemur sexual differentiation. here, hormonal correlates of prenatal development were assessed to explore the possibility that maternal androgens may shape the ma ... | 2011 | 20932838 |
| the anti-androgen combination, flutamide plus finasteride, paradoxically suppressed lh and androgen concentrations in pregnant spotted hyenas, but not in males. | the androgen receptor blocker flutamide and the 5α-reductase inhibitor finasteride have been used in a variety of species to investigate the ontogeny of sexual dimorphisms by treating pregnant females or neonates at critical periods of sexual differentiation. likewise, we have used these drugs to study the profound masculinization of the external genitalia in female spotted hyenas. however, a potential pitfall of administering flutamide, either alone or in combination with finasteride, is that i ... | 2011 | 21036174 |
| sex and the frontal cortex: a developmental ct study in the spotted hyena. | the purpose of this study was to examine developmental and individual variation in total endocranial volume and regional brain volumes, including the anterior cerebrum, posterior cerebrum and cerebellum/brain stem, in the spotted hyena (crocuta crocuta). the spotted hyena is a highly gregarious animal noted for living in large, hierarchically organized groups. the social lives of male and female spotted hyenas do not differ until after puberty, when males disperse from the natal group, while fem ... | 2010 | 21088374 |
| chemical characterization of milk oligosaccharides of an african lion (panthera leo) and a clouded leopard (neofelis nebulosa). | the carnivora include the superfamilies canoidea and feloidea. in species of canoidea other than the domestic dog, canis lupus, the milk contains only traces of lactose and much larger concentrations of oligosaccharides. in this study, lactose was found to be the dominant saccharide in the milk or colostrum of two species of feloidea, namely the african lion (panthera leo) and the clouded leopard (neofelis nebulosa). in addition to lactose, the following oligosaccharides were characterized in th ... | 2010 | 21108689 |
| brain size and social complexity: a computed tomography study in hyaenidae. | the social brain hypothesis posits that the demands of living in complex social groups require increased neural processing, and that this underlies the expansion of brain areas involved in mediation of complex social behavior. however, much of the support for the social brain hypothesis is derived from comparative studies in primates. if large brains evolved as a result of selection pressures imposed by life within complex societies, as the social brain hypothesis predicts, then gregarious nonpr ... | 2011 | 21335942 |
| tracking the feeding patterns of tsetse flies (glossina genus) by analysis of bloodmeals using mitochondrial cytochromes genes. | tsetse flies are notoriously difficult to observe in nature, particularly when populations densities are low. it is therefore difficult to observe them on their hosts in nature; hence their vertebrate species can very often only be determined indirectly by analysis of their gut contents. this knowledge is a critical component of the information on which control tactics can be developed. the objective of this study was to determine the sources of tsetse bloodmeals, hence investigate their feeding ... | 2011 | 21386971 |
| the fossil bovidae (artiodactyla, mammalia) from gesher benot ya'aqov, israel: out of africa during the early-middle pleistocene transition. | we report the study of the collection of fossil bovid specimens from the early-middle pleistocene acheulian site of gesher benot ya'aqov. this locality, situated in the levantine corridor (the bottleneck that connects africa and eurasia) is a key site to explain the faunal and human dispersals out of africa during the matuyama/brunhes boundary around 0.8ma. two species of bovine (bos sp., and bovini gen. et sp. indet. cf. bison sp.), one antelope (gazella sp. cf. g. gazella), and another indeter ... | 2010 | 21392634 |
| lifetime selection on a hypoallometric size trait in the spotted hyena. | size-related traits are common targets of natural selection, yet there is a relative paucity of data on selection among mammals, particularly from studies measuring lifetime reproductive success (lrs). we present the first phenotypic selection analysis using lrs on size-related traits in a large terrestrial carnivore, the spotted hyena, which displays a rare pattern of female-biased sexual size dimorphism (ssd). using path analysis, we investigate the operation of selection to address hypotheses ... | 2011 | 21411457 |
| ontogenetic relationships between cranium and mandible in coyotes and hyenas. | developing animals must resolve the conflicting demands of survival and growth, ensuring that they can function as infants or juveniles while developing toward their adult form. in the case of the mammalian skull, the cranium and mandible must maintain functional integrity to meet the feeding needs of a juvenile even as the relationship between parts must change to meet the demands imposed on adults. we examine growth and development of the cranium and mandible, using a unique ontogenetic series ... | 2011 | 21484852 |
| variance estimation for systematic designs in spatial surveys. | in spatial surveys for estimating the density of objects in a survey region, systematic designs will generally yield lower variance than random designs. however, estimating the systematic variance is well known to be a difficult problem. existing methods tend to overestimate the variance, so although the variance is genuinely reduced, it is over-reported, and the gain from the more efficient design is lost. the current approaches to estimating a systematic variance for spatial surveys are to app ... | 2011 | 21534940 |
| virtual endocasts: an application of computed tomography in the study of brain variation among hyenas. | reliable brain volume measurements are crucial in identifying factors that influence the course of brain evolution. here, we demonstrate the potential for using virtual endocasts (ves) to examine inter- and intraspecific variation in brain volume in members of the family hyaenidae. total endocranial volume (adjusted for body size) and anterior cerebrum volume (adjusted for endocranial volume) were greater in the spotted hyena, the most gregarious of the species, than in the other hyaenids, all o ... | 2011 | 21599694 |
| minimizing predation risk in a landscape of multiple predators: effects on the spatial distribution of african ungulates. | studies that focus on single predator-prey interactions can be inadequate for understanding antipredator responses in multi-predator systems. yet there is still a general lack of information about the strategies of prey to minimize predation risk from multiple predators at the landscape level. here we examined the distribution of seven african ungulate species in the fenced karongwe game reserve (kgr), south africa, as a function of predation risk from all large carnivore species (lion, leopard, ... | 2011 | 21618919 |
| the impact of a pathogenic bacterium on a social carnivore population. | 1. the long-term ecological impact of pathogens on group-living, large mammal populations is largely unknown. we evaluated the impact of a pathogenic bacterium, streptococcus equi ruminatorum, and other key ecological factors on the dynamics of the spotted hyena crocuta crocuta population in the ngorongoro crater, tanzania. 2. we compared key demographic parameters during two years when external signs of bacterial infection were prevalent ('outbreak') and periods of five years before and after t ... | 2011 | 21631499 |
| society, demography and genetic structure in the spotted hyena. | spotted hyenas (crocuta crocuta) are large mammalian carnivores, but their societies, called 'clans', resemble those of such cercopithecine primates as baboons and macaques with respect to their size, hierarchical structure, and frequency of social interaction among both kin and unrelated group-mates. however, in contrast to cercopithecine primates, spotted hyenas regularly hunt antelope and compete with group-mates for access to kills, which are extremely rich food sources, but also rare and ep ... | 2012 | 21880088 |
| morphology of the external genitalia of the adult male and female mice as an endpoint of sex differentiation. | adult external genitalia (exg) are the endpoints of normal sex differentiation. detailed morphometric analysis and comparison of adult mouse exg has revealed 10 homologous features distinguishing the penis and clitoris that define masculine vs. feminine sex differentiation. these features have enabled the construction of a simple metric to evaluate various intersex conditions in mutant or hormonally manipulated mice. this review focuses on the morphology of the adult mouse penis and clitoris thr ... | 2011 | 21893161 |
| Development of a hyena immunology toolbox. | Animals that hunt and scavenge are often exposed to a broad array of pathogens. Theory predicts the immune systems of animals specialized for scavenging should have been molded by selective pressures associated with surviving microbial assaults from their food. Spotted hyenas (Crocuta crocuta) are capable hunters that have recently descended from carrion feeding ancestors. Hyenas have been documented to survive anthrax and rabies infections, and outbreaks of several other viral diseases that dec ... | 2011 | 22173276 |
| phylogenetic comparisons implicate sex hormone-binding globulin in "masculinization" of the female spotted hyena (crocuta crocuta). | exposures to sex steroids during fetal development are thought to contribute to the unique urogenital anatomy and social dominance of the female spotted hyena: overt phenotypes not shared by other hyenids (i.e. striped hyena, brown hyena, and aardwolf). because both androgens and estrogens influence development of genitalia and behavior, and because plasma shbg regulates their access to tissues, we compared the shbg gene sequences, structures, and steroid-binding properties in the four extant hy ... | 2012 | 22253421 |
| coprolites as a source of information on the genome and diet of the cave hyena. | we performed high-throughput sequencing of dna from fossilized faeces to evaluate this material as a source of information on the genome and diet of pleistocene carnivores. we analysed coprolites derived from the extinct cave hyena (crocuta crocuta spelaea), and sequenced 90 million dna fragments from two specimens. the dna reads enabled a reconstruction of the cave hyena mitochondrial genome with up to a 158-fold coverage. this genome, and those sequenced from extant spotted (crocuta crocuta) a ... | 2012 | 22456883 |
| adaptability of large carnivores to changing anthropogenic food sources: diet change of spotted hyena (crocuta crocuta) during christian fasting period in northern ethiopia. | 2012 | 22486435 | |
| validation of an enzyme immunoassay for the measurement of faecal glucocorticoid metabolites in spotted hyenas (crocuta crocuta). | the use of enzyme immunoassays (eias) to measure faecal glucocorticoid metabolites (fgcm) is a useful non-invasive technique to monitor adrenocortical activity in vertebrates. the first objective of this study was to validate an 'in-house' eia (cortisol-3-cmo) for the measurement of fgcm concentrations in spotted hyenas. high-performance liquid chromatography (hplc) was used to characterise fgcm in samples from a captive hyena that received an i.v. injection of [(3)h] cortisol. all hplc fraction ... | 2012 | 22634955 |
| sibling rivalry: training effects, emergence of dominance and incomplete control. | within-brood or -litter dominance provides fitness-related benefits if dominant siblings selfishly skew access to food provided by parents in their favour. models of facultative siblicide assume that dominants exert complete control over their subordinate sibling's access to food and that control is maintained, irrespective of the subordinate's hunger level. by contrast, a recent functional hypothesis suggests that subordinates should contest access to food when the cost of not doing so is high. ... | 2012 | 22719032 |
| innovative problem solving by wild spotted hyenas. | innovative animals are those able to solve novel problems or invent novel solutions to existing problems. despite the important ecological and evolutionary consequences of innovation, we still know very little about the traits that vary among individuals within a species to make them more or less innovative. here we examine innovative problem solving by spotted hyenas (crocuta crocuta) in their natural habitat, and demonstrate for the first time in a non-human animal that those individuals exhib ... | 2012 | 22874748 |
| evidence for a bacterial mechanism for group-specific social odors among hyenas. | symbiotic microbes can benefit their animal hosts by enhancing the diversity of communication signals available to them. the fermentation hypothesis for chemical recognition posits that 1) fermentative bacteria in specialized mammalian scent glands generate odorants that mammals co-opt to communicate with one another, and 2) that variation in scent gland odors is due to underlying variation in the structure of bacterial communities within scent glands. for example, group-specific social odors ar ... | 2012 | 22937224 |
| evidence for chlamydia in wild mammals of the serengeti. | only limited information is available on the presence of chlamydiaceae in wildlife, a deficit that is particularly acute concerning mammalian wildlife in africa. in a retrospective analysis of organ material from an earlier study on wild mammals from the seregenti national park, 521 samples from 54 animals of 14 mammalian species were investigated. the presence of chlamydiaceae was analyzed using molecular methods and immunohistochemistry. chlamydial dna was detected by real-time polymerase chai ... | 2012 | 23060512 |
| coronavirus genotype diversity and prevalence of infection in wild carnivores in the serengeti national park, tanzania. | knowledge of coronaviruses in wild carnivores is limited. this report describes coronavirus genetic diversity, species specificity and infection prevalence in three wild african carnivores. coronavirus rna was recovered from fresh feces from spotted hyena and silver-backed jackal, but not bat-eared fox. analysis of sequences of membrane (m) and spike (s) gene fragments revealed strains in the genus alphacoronavirus, including three distinct strains in hyenas and one distinct strain in a jackal. ... | 2013 | 23212740 |
| determinants of persistence and tolerance of carnivores on namibian ranches: implications for conservation on southern african private lands. | changing land use patterns in southern africa have potential to dramatically alter the prospects for carnivore conservation. understanding these influences is essential for conservation planning. we interviewed 250 ranchers in namibia to assess human tolerance towards and the distribution of large carnivores. cheetahs (acinonyx jubatus), leopards (panthera pardus) and brown hyaenas (hyaena brunnea) were widely distributed on namibian farmlands, spotted hyaenas (crocuta crocuta) had a narrower di ... | 2013 | 23326333 |
| comparison of the effects of artificial and natural barriers on large african carnivores: implications for interspecific relationships and connectivity. | 1. physical barriers contribute to habitat fragmentation, influence species distribution and ranging behaviour, and impact long-term population viability. barrier permeability varies among species and can potentially impact the competitive balance within animal communities by differentially affecting co-occurring species. the influence of barriers on the spatial distribution of species within whole communities has nonetheless received little attention. 2. during a 4-year period, we studied the i ... | 2013 | 23402594 |
| complete genome sequence of the crocuta crocuta papillomavirus type 1 (ccrpv1) from a spotted hyena, the first papillomavirus characterized in a member of the hyaenidae. | we report the complete genomic sequence of the crocuta crocuta papillomavirus type 1 (ccrpv1), isolated from an oral papillomatous lesion of a wild spotted hyena. this virus is the first papillomavirus found in a species belonging to the hyaenidae family of carnivores, and it can be classified in the genus lambdapapillomavirus. | 2013 | 23405364 |
| fear of the dark or dinner by moonlight? reduced temporal partitioning among africa's large carnivores. | africa is home to the last intact guild of large carnivores and thus provides the only opportunity to investigate mechanisms of coexistence among large predator species. strong asymmetric dominance hierarchies typically characterize guilds of large carnivores; but despite this asymmetry, subdominant species may persist alongside their stronger counterparts through temporal partitioning of habitat and resources. in the african guild, the subdominant african wild dogs and cheetahs are routinely de ... | 2012 | 23431590 |
| rabies virus and canine distemper virus in wild and domestic carnivores in northern kenya: are domestic dogs the reservoir? | rabies virus (rv) and canine distemper virus (cdv) can cause significant mortality in wild carnivore populations, and rv threatens human lives. we investigated serological patterns of exposure to cdv and rv in domestic dogs (canis familiaris), african wild dogs (lycaon pictus), black-backed jackals (canis mesomelas), spotted hyenas (crocuta crocuta), striped hyenas (hyaena hyaena) and african lions (panthera leo), over a 10-year period, in a kenyan rangeland to assess the role domestic dogs may ... | 2012 | 23459924 |
| risk avoidance in sympatric large carnivores: reactive or predictive? | 1. risks of predation or interference competition are major factors shaping the distribution of species. an animal's response to risk can either be reactive, to an immediate risk, or predictive, based on preceding risk or past experiences. the manner in which animals respond to risk is key in understanding avoidance, and hence coexistence, between interacting species. 2. we investigated whether cheetahs (acinonyx jubatus), known to be affected by predation and competition by lions (panthera leo) ... | 2013 | 23692142 |
| papillomavirus-associated cutaneous papillomas in a population of wild spotted hyenas (crocuta crocuta). | beginning in 1997 michigan state university mara hyena project investigators observed waxing and waning progression of oral and genital masses during long-term behavioral observations of a population of wild spotted hyenas (crocuta crocuta) from the masai mara game reserve, kenya. from 1999-2000, we darted adult spotted hyenas to obtain routine physiologic and hematologic data and collected small, raised, lobulated, pigmented masses from the oral or genital areas of eight animals. microscopicall ... | 2013 | 23778611 |
| rabies, canine distemper, and canine parvovirus exposure in large carnivore communities from two zambian ecosystems. | disease transmission within and among wild and domestic carnivores can have significant impacts on populations, particularly for threatened and endangered species. we used serology to evaluate potential exposure to rabies virus, canine distemper virus (cdv), and canine parvovirus (cpv) for populations of african lions (panthera leo), african wild dogs (lycaon pictus), and spotted hyenas (crocuta crocuta) in zambia's south luangwa national park (slnp) and liuwa plain national park (lpnp) as well ... | 2013 | 23805791 |
| symbiotic bacteria appear to mediate hyena social odors. | all animals harbor beneficial microbes. one way these microbes can benefit their animal hosts is by increasing the diversity and efficacy of communication signals available to the hosts. the fermentation hypothesis for mammalian chemical communication posits that bacteria in the scent glands of mammals generate odorous metabolites used by their hosts for communication and that variation in host chemical signals is a product of underlying variation in the bacterial communities inhabiting the scen ... | 2013 | 24218592 |
| two new species of cylicospirura vevers, 1922 (nematoda: spirocercidae) from carnivores in southern africa, with validation of the related genera gastronodus singh, 1934 and skrjabinocercina matschulsky, 1952. | two new species of cylicospirura vevers, 1922 are described from carnivores from southern africa. cylicospirura crocutae junker et mutafchiev sp. n. from crocuta crocuta (erxleben) in zimbabwe is distinguished from its congeners by combinations of characters, including the presence of four cephalic and four external labial papillae, while internal labial papillae were not distinct, the presence of groups of small accessory teeth between the six large tricuspid teeth, the fifth and the sixth pair ... | 2013 | 24261135 |
| pleistocene chinese cave hyenas and the recent eurasian history of the spotted hyena, crocuta crocuta. | the living hyena species (spotted, brown, striped and aardwolf) are remnants of a formerly diverse group of more than 80 fossil species, which peaked in diversity in the late miocene (about 7-8 ma). the fossil history indicates an african origin, and morphological and ancient dna data have confirmed that living spotted hyenas (crocuta crocuta) of africa were closely related to extinct late pleistocene cave hyenas from europe and asia. the current model used to explain the origins of eurasian cav ... | 2014 | 24320717 |
| prevalence and diversity of babesia, hepatozoon, ehrlichia, and bartonella in wild and domestic carnivores from zambia, africa. | a molecular survey was conducted for several hemoparasites of domestic dogs and three species of wild carnivores from two sites in zambia. three babesia spp. were detected including babesia felis and babesia leo in lions (panthera leo) and a babesia sp. (similar to babesia lengau) in spotted hyenas (crocuta crocuta) and a single lion. all wild dogs (lycaon pictus) and domestic dogs were negative for babesia. high prevalences for hepatozoon were noted in all three wild carnivores (38-61%) and in ... | 2014 | 24363181 |
| squamous cell carcinoma of the anal sac in a spotted hyena (crocuta crocuta). | a 25-yr-old spayed female spotted hyena (crocuta crocuta) developed intermittent right pelvic limb lameness that persisted following conservative medical therapy. no obvious musculoskeletal lesions were noted on initial physical exam; however, spinal radiography was suspicious for possible intervertebral degenerative joint disease or discospondylitis. despite prolonged medical therapy, the lameness progressed to minimal weight bearing and marked muscle atrophy of the right pelvic limb. electromy ... | 2013 | 24450071 |
| underestimating the frequency, strength and cost of antipredator responses with data from gps collars: an example with wolves and elk. | field studies that rely on fixes from gps-collared predators to identify encounters with prey will often underestimate the frequency and strength of antipredator responses. these underestimation biases have several mechanistic causes. (1) step bias: the distance between successive gps fixes can be large, and encounters that occur during these intervals go undetected. this bias will generally be strongest for cursorial hunters that can rapidly cover large distances (e.g., wolves and african wild ... | 2013 | 24455148 |
| characterization of toll-like receptors 1-10 in spotted hyenas. | previous research has shown that spotted hyenas (crocuta crocuta) regularly survive exposure to deadly pathogens such as rabies, canine distemper virus, and anthrax, suggesting that they have robust immune defenses. toll-like receptors (tlrs) recognize conserved molecular patterns and initiate a wide range of innate and adaptive immune responses. tlr genes are evolutionarily conserved, and assessing tlr expression in various tissues can provide insight into overall immunological organization and ... | 2014 | 24488231 |
| factors influencing dipylidium sp. infection in a free-ranging social carnivore, the spotted hyaena (crocuta crocuta). | we provide the first genetic sequence data for a dipylidium species from a wild carnivore plus an analysis of the effects of ecological, demographic, physiological and behavioural factors on dipylidium sp. infection prevalence in a social carnivore, the spotted hyaena (crocuta crocuta), in the serengeti national park, tanzania. our sequence data from a mitochondrial gene fragment (1176 base pair long) had a similarity of between 99% and 89% to dipylidium caninum. we determined infection prevalen ... | 2013 | 24533344 |
| hormone-independent pathways of sexual differentiation. | new observations over the last 25 years of hormone-independent sexual dimorphisms have gradually and unequivocally overturned the dogma, arising from jost's elegant experiments in the mid-1900s, that all somatic sex dimorphisms in vertebrates arise from the action of gonadal hormones. although we know that sry, a y-linked gene, is the primary gonadal sex determinant in mammals, more recent analysis in marsupials, mice, and finches has highlighted numerous sexual dimorphisms that are evident well ... | 2014 | 24577198 |
| development of the external genitalia: perspectives from the spotted hyena (crocuta crocuta). | this review/research paper summarizes data on development of the external genitalia of the spotted hyena, a fascinating mammal noted for extreme masculinization of the female external genitalia. the female spotted hyena is the only extant mammal that mates and gives birth through a pendulous penis-like clitoris. our studies indicate that early formation of the phallus in both males and females is independent of androgens; indeed the phallus forms before the fetal testes or ovaries are capable of ... | 2016 | 24582573 |
| a survey for echinococcus spp. of carnivores in six wildlife conservation areas in kenya. | to investigate the presence of echinococcus spp. in wild mammals of kenya, 832 faecal samples from wild carnivores (lions, leopards, spotted hyenas, wild dogs and silver-backed jackals) were collected in six different conservation areas of kenya (meru, nairobi, tsavo west and tsavo east national parks, samburu and maasai mara national reserves). taeniid eggs were found in 120 samples (14.4%). in total, 1160 eggs were isolated and further analysed using rflp-pcr of the nad1 gene and sequencing. 3 ... | 2014 | 24732034 |
| phylogenetic characterisation of taenia tapeworms in spotted hyenas and reconsideration of the "out of africa" hypothesis of taenia in humans. | the african origin of hominins suggests that taenia spp. in african carnivores are evolutionarily related to the human-infecting tapeworms taenia solium, taenia saginata and taenia asiatica. nevertheless, the hypothesis has not been verified through molecular phylogenetics of taenia. this study aimed to perform phylogenetic comparisons between taenia spp. from african hyenas and the congeneric human parasites. during 2010-2013, 233 adult specimens of taenia spp. were collected from 11 spotted hy ... | 2014 | 24815426 |
| space use of african wild dogs in relation to other large carnivores. | interaction among species through competition is a principle process structuring ecological communities, affecting behavior, distribution, and ultimately the population dynamics of species. high competition among large african carnivores, associated with extensive diet overlap, manifests in interactions between subordinate african wild dogs (lycaon pictus) and dominant lions (panthera leo) and spotted hyenas (crocuta crocuta). using locations of large carnivores in hluhluwe-imfolozi park, south ... | 2014 | 24896638 |
| landscape suitability in botswana for the conservation of its six large african carnivores. | wide-ranging large carnivores often range beyond the boundaries of protected areas into human-dominated areas. mapping out potentially suitable habitats on a country-wide scale and identifying areas with potentially high levels of threats to large carnivore survival is necessary to develop national conservation action plans. we used a novel approach to map and identify these areas in botswana for its large carnivore guild consisting of lion (panthera leo), leopard (panthera pardus), spotted hyae ... | 2014 | 24949735 |
| an objective approach to determining the weight ranges of prey preferred by and accessible to the five large african carnivores. | broad-scale models describing predator prey preferences serve as useful departure points for understanding predator-prey interactions at finer scales. previous analyses used a subjective approach to identify prey weight preferences of the five large african carnivores, hence their accuracy is questionable. this study uses a segmented model of prey weight versus prey preference to objectively quantify the prey weight preferences of the five large african carnivores. based on simulations of known ... | 2014 | 24988433 |
| the "bear" essentials: actualistic research on ursus arctos arctos in the spanish pyrenees and its implications for paleontology and archaeology. | neotaphonomic studies of large carnivores are used to create models in order to explain the formation of terrestrial vertebrate fossil faunas. the research reported here adds to the growing body of knowledge on the taphonomic consequences of large carnivore behavior in temperate habitats and has important implications for paleontology and archaeology. using photo- and videotrap data, we were able to describe the consumption of 17 ungulate carcasses by wild brown bears (ursus arctos arctos) rangi ... | 2014 | 25029167 |
| limited social learning of a novel technical problem by spotted hyenas. | social learning can have profound evolutionary consequences because it drives the diffusion of novel behaviours among individuals and promotes the maintenance of traditions within populations. we inquired whether spotted hyenas (crocuta crocuta), generalist carnivores living in complex, primate-like societies, acquire information from conspecifics about a novel problem-solving task. previously, we presented wild hyenas with a food-access puzzle and found that social learning opportunities did no ... | 2014 | 25245305 |
| differential effects of temperature change and human impact on european late quaternary mammalian extinctions. | species that inhabited europe during the late quaternary were impacted by temperature changes and early humans, resulting in the disappearance of half of the european large mammals. however, quantifying the relative importance that each factor had in the extinction risk of species has been challenging, mostly due to the spatio-temporal biases of fossil records, which complicate the calibration of realistic and accurate ecological niche modeling. here, we overcome this problem by using ecotypes, ... | 2015 | 25311114 |
| the lion king and the hyaena queen: large carnivore interactions and coexistence. | interactions among species, which range from competition to facilitation, have profound effects on ecosystem functioning. large carnivores are of particular importance in shaping community structure since they are at the top of the food chain, and many efforts are made to conserve such keystone species. despite this, the mechanisms of carnivore interactions are far from understood, yet they are key to enabling or hindering their coexistence and hence are highly relevant for their conservation. t ... | 2015 | 25530248 |
| molecular characterization of canine kobuvirus in wild carnivores and the domestic dog in africa. | knowledge of kobuvirus (family picornaviridae) infection in carnivores is limited and has not been described in domestic or wild carnivores in africa. to fill this gap in knowledge we used rt-pcr to screen fresh feces from several african carnivores. we detected kobuvirus rna in samples from domestic dog, golden jackal, side-striped jackal and spotted hyena. using next generation sequencing we obtained one complete kobuvirus genome sequence from each of these species. our phylogenetic analyses r ... | 2015 | 25667111 |
| first report of a mixed infection of trichinella nelsoni and trichinella t8 in a leopard (panthera pardus) from the greater kruger national park, south africa. | at least three trichinella species, namely trichinella nelsoni, trichinella britovi and trichinella zimbabwensis, and one genotype (trichinella t8), have been isolated from sylvatic carnivores on the african continent. with the exception of t. britovi, the other species are known to circulate in wildlife of the kruger national park (knp), south africa, and knp neighbouring game reserves (collectively known as the greater knp area). lions (panthera leo) and spotted hyenas (crocuta crocuta) appear ... | 2014 | 25686214 |
| a comparison of antiserum and protein a as secondary reagents to assess toxoplasma gondii antibody titers in cats and spotted hyenas. | toxoplasma gondii is a protozoal parasite with worldwide distribution that is able to infect a wide variety of mammals and birds. our main goal was to screen for t. gondii antibody titers in a previously untested species, the spotted hyena ( crocuta crocuta); however, this goal first required us to investigate serological procedures that could be suitable for hyenas. cats are the closest domestic relations of hyenas, so t. gondii antibody titers were first compared in 26 feral cats with specific ... | 2015 | 25710628 |
| socioecological variables predict telomere length in wild spotted hyenas. | telomeres are regarded as important biomarkers of ageing and serve as useful tools in revealing how stress acts at the cellular level. however, the effects of social and ecological factors on telomere length remain poorly understood, particularly in free-ranging mammals. here, we investigated the influences of within-group dominance rank and group membership on telomere length in wild adult spotted hyenas (crocuta crocuta). we found large effects of both factors; high-ranking hyenas exhibited si ... | 2015 | 25716089 |
| effects of trophy hunting leftovers on the ranging behaviour of large carnivores: a case study on spotted hyenas. | human-related food resources such as garbage dumps and feeding sites have been shown to significantly influence space use, breeding success and population dynamics in a variety of animal species. in contrast, relatively little is known on the effects of unpredictable sources of food, such as carcasses discarded by hunters, on carnivore species. we evaluated the effect of elephant carcasses, mainly deriving from trophy hunting, on the ranging and feeding behavior of spotted hyenas (crocuta crocut ... | 2015 | 25793976 |
| a sylvatic lifecycle of echinococcus equinus in the etosha national park, namibia. | various species of echinococcus have been described in the past from wild mammals of sub-saharan africa. however, it is only recently, that a few isolates have become available for molecular identification; therefore, the involvement of wildlife in the lifecycles of the various cryptic species within echinococcus granulosus sensu lato is still only partially known. a preliminary survey was undertaken in etosha national park, namibia, from august to october 2012. faecal samples were obtained from ... | 2015 | 25830103 |
| long-distance communication facilitates cooperation among wild spotted hyaenas, crocuta crocuta. | calls that catalyse group defence, as in the mobbing of predators, appear to facilitate cooperation by recruiting receivers to act collectively. however, even when such signals reliably precede cooperative behaviour, the extent to which the calls function as recruitment signals is unclear. calls might simply arouse listeners' attention, setting off a cascade of independent responses to the threat. by contrast, they might convey information, for example, about signaller identity and the nature of ... | 2015 | 25908882 |