| lymphosarcoma in a spotted hyena, crocuta crocuta. | lymphosarcoma of the mesenteric and mediastinal lymph nodes with peritoneal and mediastinal implantations, as well as widespread intravascular metastases and thrombosis with haemorrhages was diagnosed in a spotted hyena. | 1983 | 6689181 |
| the chorioallantoic placenta of the spotted hyena (crocuta crocuta erxleben): an electron microscopic study. | the histology and ultrastructure of the chorioallantoic placenta of the spotted hyena have been studied in three specimens obtained in the field and fixed promptly with glutaraldehyde. observations revealed that the interhemal membrane at its minimal thickness is hemomonochorial, consisting of a continuous layer of syncytial trophoblast, a basal lamina, and fetal capillary endothelium. cytotrophoblastic cells form a discontinuous layer beneath the syncytial trophoblast and are distinguished by t ... | 1982 | 7158827 |
| fetal androgens and sexual mimicry in spotted hyaenas (crocuta crocuta). | sexual differentiation of the müllerian duct system and gonad in female fetuses conformed to the general mammalian pattern, whereas the external genital anlage in male and female fetuses developed into the male facies. interstitial cells occurred in the primary germinal cords of both male and female fetal gonads and are suggested to be the source of androgen production in spotted hyaena fetuses. maternal transfer of androgens to the fetus via the placenta was negligible. male fetuses had higher ... | 1982 | 7097645 |
| sexual dimorphism of the phallus in spotted hyaena (crocuta crocuta). | the weight of the skinned phallus and the diameter of its shaft and glans did not differ significantly in the two sexes of spotted hyaena, but phallus length was greater in males. the urethra of the penis was surrounded by corpus spongiosum, while the urogenital canal of the clitoris was suspended beneath the erectile bodies in loose connective tissue, an arrangement compatible with dilatation of the canal during copulation and parturition. the average width of the phallic meatus in juvenile fem ... | 1980 | 7431309 |
| sexual differentiation in three unconventional mammals: spotted hyenas, elephants and tammar wallabies. | the present review explores sexual differentiation in three non-conventional species: the spotted hyena, the elephant and the tammar wallaby, selected because of the natural challenges they present for contemporary understanding of sexual differentiation. according to the prevailing view of mammalian sexual differentiation, originally proposed by alfred jost, secretion of androgen and anti-mullerian hormone (amh) by the fetal testes during critical stages of development accounts for the full ran ... | 2005 | 16197946 |
| defense of females, but not social status, predicts plasma androgen levels in male spotted hyenas. | a positive correlation between male social status and testosterone levels is expected and often found in social species with high rates of agonistic interactions or when social relationships among males are unstable. in contrast, in species with low rates of agonistic interactions or when social relationships are stable, testosterone levels should not correlate with social status. the "challenge hypothesis" predicts that androgen levels should rise during periods of courtship or mate guarding. w ... | 2006 | 13130437 |
| prevalence and molecular identification of trichinella species isolated from wildlife originating from limpopo and mpumalanga provinces of south africa. | trichinella species are widely distributed on all continents with the exception of antarctica, although the full spectrum of trichinella species found in sub-saharan african countries, and their hosts, has not been fully documented. this study was conducted to determine the prevalence of trichinella in wildlife from the greater kruger national park (gknp) and adjacent areas located in the limpopo and mpumalanga provinces of south africa, and to identify the species and/or genotypes of trichinell ... | 2017 | 29168444 |
| the occurrence of some nonblood protozoan parasites in wild and domestic mammals in south africa. | relatively little is known about protozoan parasites in african animals. here we investigated the occurrence of protozoan parasites in mammals from south africa. oocysts of protozoan parasites were detected in 13 of 56 (23%) fecal samples using conventional microscopic examination methods. cryptosporidium spp. and isospora spp. were detected in eight (14 %) and five (9 %) samples, respectively. mixed parasitic infection of cryptosporidium spp. and isospora spp. was recorded in banded mongoose ( ... | 2018 | 29369722 |
| spotted hyenas. | | 2006 | 17113370 |
| a mobile laboratory for ancient dna analysis. | mobile devices for on-field dna analysis have been used for medical diagnostics at the point-of-care, forensic investigations and environmental surveys, but still have to be validated for ancient dna studies. we report here on a mobile laboratory that we setup using commercially available devices, including a compact real-time pcr machine, and describe procedures to perform dna extraction and analysis from a variety of archeological samples within 4 hours. the process is carried out on 50 mg sam ... | 2020 | 32187203 |
| 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 |
| a preliminary survey of medium and large-sized mammals from lebu natural protected forest, southwest showa, ethiopia. | this study was conducted to determine the species composition and diversity of medium and large-sized mammals from lebu natural protected forest, ethiopia. surveys were conducted to record mammals through direct observation and indirect evidence from three habitat types, namely: natural forest, bushland, and riverine forest. a total of 15 mammalian species were recorded. the species recorded were papio anubis, chlorocebus aethiops, tragelaphus scriptus, canis aureus, crocuta crocuta, panthera pa ... | 2019 | 31832163 |
| social status does not predict corticosteroid levels in postdispersal male spotted hyenas. | in social species with low rates of direct male competition levels of corticosteroids should not correlate with social status. male spotted hyenas acquire social status by observing strict queuing conventions over many years, and thus levels of male-male aggression are low, and male social status and tenure are closely correlated. in this study, we investigated whether the low rate of direct male competition in spotted hyenas was reflected in fecal corticosteroid levels of adult males in the ser ... | 2003 | 12788293 |
| patterns of livestock depredation and cost-effectiveness of fortified livestock enclosures in northern tanzania. | human-carnivore conflicts and retaliatory killings contribute to carnivore populations' declines around the world. strategies to mitigate conflicts have been developed, but their efficacy is rarely assessed in a randomized case-control design. further, the economic costs prevent the adoption and wide use of conflict mitigation strategies by pastoralists in rural africa. we examined carnivore (african lion [panthera leo], leopard [panthera pardus], spotted hyena [crocuta crocuta], jackal [canis m ... | 2019 | 31641483 |
| the evolution of matrilineal social systems in fissiped carnivores. | we review matrilineal relationships in the societies of fissiped mammalian carnivores, focusing on how the most complex of these may have evolved from simpler systems. although competition for food is very intense at the trophic level occupied by most carnivores, and although most species of extant fissiped carnivores therefore lead solitary lives, some species show at least rudimentary clustering of maternal kin and matrilineal resource-sharing or transmission of critical resources between gene ... | 2019 | 31303158 |
| intrinsic qualities of primate bones as predictors of skeletal element representation in modern and fossil carnivore feeding assemblages. | plio-pleistocene faunal assemblages from swartkrans cave (south africa) preserve large numbers of primate remains. brain, c.k., 1981. the hunters or the hunted? an introduction to african cave taphonomy. university of chicago press, chicago suggested that these primate subassemblages might have resulted from a focus by carnivores on primate predation and bone accumulation. brain's hypothesis prompted us to investigate, in a previous study, this taphonomic issue as it relates to density-mediated ... | 2003 | 12727462 |
| multispecies hierarchical modeling reveals variable responses of african carnivores to management alternatives. | carnivore communities face unprecedented threats from humans. yet, management regimes have variable effects on carnivores, where species may persist or decline in response to direct or indirect changes to the ecosystem. using a hierarchical multispecies modeling approach, we examined the effects of alternative management regimes (i.e., active vs. passive enforcement of regulations) on carnivore abundances and group sizes at both species and community levels in the masai mara national reserve, ke ... | 2019 | 30694574 |
| a multispecies assessment of wildlife impacts on local community livelihoods. | conflicts between the interests of agriculture and wildlife conservation are a major threat to biodiversity and human well-being globally. addressing such conflicts requires a thorough understanding of the impacts associated with living alongside protected wildlife. despite this, most studies reporting on human-wildlife impacts and the strategies used to mitigate them focus on a single species, thus oversimplifying often complex systems of human-wildlife interactions. we sought to characterize t ... | 2020 | 32496643 |
| on sexual behavior and sex-role reversal. | sex is not about reproduction; sex is about (re-)combination of dna. sex, not reproduction, always involves physical contact between two individuals; to achieve this, strategies of sexual behavior evolved. sexual behavior, therefore, did not evolve as part of a reproductive strategy, but evolved to enable exchange of genetic material. in multicellular organisms the situation is more complicated than in unicellular organisms, as it is impossible for each cell within a multicellular body to have s ... | 2005 | 16295520 |
| evidence of high exposure to toxoplasma gondii in free-ranging and captive african carnivores. | toxoplasma gondii is an ubiquitous intracellular protozoan parasite. mammals and birds are intermediate hosts and felid species are definitive hosts. in most human altered habitats the domestic cat is the predominant definitive host. current knowledge of t. gondii infection in african ecosystems is limited. this study aimed to assess exposure to t. gondii in wild carnivores in the serengeti ecosystem in east africa. carnivores can be infected by the consumption of tissue cysts when feeding on in ... | 2019 | 30740303 |
| sexual mimicry in hyenas. | genital masculinization in female spotted hyenas has been widely explained as an incidental consequence of high androgen levels. high androgen levels, in turn, were supposed to be favored because they led to adaptive aggressive behavior. incidental androgenization is no longer a tenable hypothesis, however, because genital masculinization has been shown to proceed in the absence of androgenic steroids. thus, an alternative hypothesis is required. the genitals of spotted hyena females are not sim ... | 2002 | 11963460 |
| palaeoproteomic analysis of pleistocene cave hyenas from east asia. | the spotted hyena (crocuta crocuta) is the only extant species of the genus crocuta, which once occupied a much wider range during the pliocene and pleistocene. however, its origin and evolutionary history is somewhat contentious due to discordances between morphological, nuclear, and mitochondrial data. due to the limited molecular data from east asian crocuta, also known as cave hyena, and the difficulty of extracting ancient dna from this area, here we present proteomic analysis of cave hyena ... | 2020 | 33028848 |
| an improved spotted hyena optimizer for pid parameters in an avr system. | in this paper, an improved spotted hyena optimizer (isho) with a nonlinear convergence factor is proposed for proportional integral derivative (pid) parameter optimization in an automatic voltage regulator (avr). in the proposed isho, an opposition-based learning strategy is used to initialize the spotted hyena individual's position in the search space, which strengthens the diversity of individuals in the global searching process. a novel nonlinear update equation for the convergence factor is ... | 2020 | 32987554 |
| social, state-dependent and environmental modulation of faecal corticosteroid levels in free-ranging female spotted hyenas. | little is known about to what extent the sensitivity of the hypothalamic-pituitary-adrenal (hpa) axis may be state dependent and vary in the same species between environments. here we tested whether the faecal corticosteroid concentrations of matrilineal adult female spotted hyenas are influenced by social and reproductive status in adjacent ecosystems and whether they vary between periods with and without social stress. females in the serengeti national park frequently become socially subordina ... | 2001 | 11747563 |
| the story of the spotted hyena and the hermaphrodite: biological order and enigma. | the complex problem of genital masculinization is illustrated in this article from the perspectives of comparative zoology, and pediatric plastic surgery on intersex children. in addition, criticism and recommendations coming from patient internet communications are introduced into the medical community. | 2000 | 10994184 |
| a sex difference in the hypothalamus of the spotted hyena. | | 1999 | 10526331 |
| social facilitation, affiliation, and dominance in the social life of spotted hyenas. | | 1997 | 9071350 |
| a draft genome assembly of spotted hyena, crocuta crocuta. | the spotted hyena (crocuta crocuta), one of the largest terrestrial predators native to sub-saharan africa, is well known for its matriarchal social system and large-sized social group in which larger females dominate smaller males. spotted hyenas are highly adaptable predators as they both actively hunt prey and scavenge kills by other predators, and possess an enhanced hypercarnivorous dentition that allows them to crack open bones and thereby feed on nearly all parts of a carcass. here, we pr ... | 2020 | 32345970 |
| cross-species transmission and evolutionary dynamics of canine distemper virus during a spillover in african lions of serengeti national park. | the outcome of pathogen spillover from a reservoir to a novel host population can range from a "dead-end" when there is no onward transmission in the recipient population, to epidemic spread and even establishment in new hosts. understanding the evolutionary epidemiology of spillover events leading to discrete outcomes in novel hosts is key to predicting risk and can lead to a better understanding of the mechanisms of emergence. here we use a bayesian phylodynamic approach to examine cross-speci ... | 2020 | 32306443 |
| why do some males choose to breed at home when most other males disperse? | dispersal is a key driver of ecological and evolutionary processes. despite substantial efforts to explain the evolution of dispersal, we still do not fully understand why individuals of the same sex of a species vary in their propensity to disperse. the dominant hypothesis emphasizes movements and assumes that leaving home (dispersal) and staying at home (philopatry) are two alternative strategies providing different fitness. it suggests that only individuals of high phenotypic quality can purs ... | 2016 | 27034982 |
| topological effects of network structure on long-term social network dynamics in a wild mammal. | social structure influences ecological processes such as dispersal and invasion, and affects survival and reproductive success. recent studies have used static snapshots of social networks, thus neglecting their temporal dynamics, and focused primarily on a limited number of variables that might be affecting social structure. here, instead we modelled effects of multiple predictors of social network dynamics in the spotted hyena, using observational data collected during 20 years of continuous f ... | 2015 | 25975663 |
| 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 |
| 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 |
| 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 |
| 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 |
| taphonomic bone trauma caused by southern african scavengers. | forensic anthropologists in southern africa are often confronted with post-mortem modifications of human skeletal remains caused by animal scavenging. this is troublesome as the post-mortem pseudo-trauma could be misinterpreted. this study aimed to describe the skeletal trauma caused by southern african scavengers which are of forensic interest. the scavenging animals selected for this study included wild dog, spotted hyena, lion, leopard, black-backed jackal, caracal, and porcupine housed at th ... | 2020 | 31471653 |
| c-hmoshssa: gene selection for cancer classification using multi-objective meta-heuristic and machine learning methods. | over the last two decades, dna microarray technology has emerged as a powerful tool for early cancer detection and prevention. it helps to provide a detailed overview of disease complex microenvironment. moreover, online availability of thousands of gene expression assays made microarray data classification an active research area. a common goal is to find a minimum subset of genes and maximizing the classification accuracy. | 2019 | 31416551 |
| 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 |
| can hyena behaviour provide information on population trends of sympatric carnivores? | mammalian carnivores are declining worldwide owing to human activities. behavioural indicators have the potential to help identify population trends and inform conservation actions, although this area of research is understudied. we investigate whether behaviour is linked to abundance in a community of carnivores in the masai mara national reserve, kenya. anthropogenic disturbance increased exponentially in parts of the reserve between 1988 and 2017, mainly owing to daily incursions by large num ... | 2019 | 31352879 |
| early life social and ecological determinants of global dna methylation in wild spotted hyenas. | environmental factors early in life can have lasting influence on the development and phenotypes of animals, but the underlying molecular modifications remain poorly understood. we examined cross-sectional associations among early life socioecological factors and global dna methylation in 293 wild spotted hyenas (crocuta crocuta) in the masai mara national reserve, kenya, grouped according to three age classes (cub, subadult and adult). explanatory variables of interest included annual maternal ... | 2019 | 31291495 |
| 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 |
| what do sex, twins, spotted hyenas, adhd, and sexual orientation have in common? | the otoacoustic emissions (oaes) measured in a collection of special populations of humans and certain nonhuman species suggest that oaes may provide a window into some processes of human prenatal development and sexual differentiation. for reasons that are unclear, oaes appear to be highly sensitive to events occurring during prenatal development that seem to be related to the degree of exposure to androgens a fetus receives. the (largely circumstantial) evidence for a relationship between andr ... | 2008 | 26158951 |
| molecular identification of bloodmeal sources and trypanosomes in glossina spp., tabanus spp. and stomoxys spp. trapped on cattle farm settlements in southwest nigeria. | the interactions of host, vector and parasite in bovine trypanosomiasis transmission cycles in southwest nigeria are not yet well understood. trypanosoma (trypanosomatida: trypanosomatidae) species infection prevalences and bloodmeal sources were determined in transmitting vectors of the genera glossina (diptera: glossinidae), tabanus (diptera: tabanidae) and stomoxys (diptera: muscidae) collected using nzi traps in cattle settlements in southwest nigeria. sequenced cytochrome b mitochondrial dn ... | 2019 | 30730048 |
| slow recovery from a disease epidemic in the spotted hyena, a keystone social carnivore. | predicting the impact of disease epidemics on wildlife populations is one of the twenty-first century's main conservation challenges. the long-term demographic responses of wildlife populations to epidemics and the life history and social traits modulating these responses are generally unknown, particularly for k-selected social species. here we develop a stage-structured matrix population model to provide a long-term projection of demographic responses by a keystone social predator, the spotted ... | 2018 | 30480102 |
| the birth and survival of wildebeest calves. | this paper describes social organization, parturition, post partum behavior of wildebeest mothers and offspring, and calf predation during the annual birth peak in ngorongoro crater, tanzania. the wildebeest's "follower-calf" system, unique among the bovidae, is remarkably effective in protecting neonates. even during hte one-month peak, the major predator on calves, the spotted hyena, is unable to feed to satiation. calf survival is consistently high, despite large fluctuations in the numbers o ... | 1979 | 494841 |
| first molecular identification of kobuviruses in wolves (canis lupus) in italy. | canine kobuviruses (cakovs) were first identified in diarrhoeic and asymptomatic dogs in 2011 in the usa. subsequent studies have demonstrated a worldwide distribution of these viruses, but it is not clear if cakovs play a role as enteric pathogens of dogs. more recently, cakov rna has been detected in wild carnivores, including red fox, golden jackal, side-striped jackal and spotted hyena. in this study, we addressed the hypothesis that wolves are susceptible to cakov infections. a total of 185 ... | 2018 | 29101539 |
| clitoral length in immature and mature captive tufted capuchin (sapajus spp.) females: a cross-sectional study. | quantitative data on female external genital morphology are sporadic in the primate literature, and the intraspecific and interfemale variation is especially under investigated (e.g., external clitoris length). since in most anthropoid primate species female external genitals are relatively small and often hidden, for those species whose external clitoris is described as hypertrophic, external genital resemblance may represent a source of confusion in distinguishing the sexes at a distance. this ... | 2020 | 32319142 |
| androgen-independent events in penile development in humans and animals. | the common view on penile development is that it is androgen-dependent, based first and foremost on the fact that the genital tubercle forms a penis in males and a clitoris in females. however, critical examination of the complex processes involved in human penile development reveals that many individual steps in development of the genital tubercle are common to both males and females, and thus can be interpreted as androgen-independent. for certain developmental events this conclusion is bolste ... | 2020 | 31783219 |
| social status mediates the fitness costs of infection with canine distemper virus in serengeti spotted hyenas. | the extent to which the fitness costs of infection are mediated by key life-history traits such as age or social status is still unclear. within populations, individual heterogeneity in the outcome of infection is the result of two successive processes; the degree of contact with the pathogen (exposure) and the immune response to infection. in social mammals, because individuals holding high social status typically interact more frequently with group members, they should be more often in contact ... | 2018 | 32313354 |
| proactive behavior, but not inhibitory control, predicts repeated innovation by spotted hyenas tested with a multi-access box. | innovation is widely linked to cognitive ability, brain size, and adaptation to novel conditions. however, successful innovation appears to be influenced by both cognitive factors, such as inhibitory control, and non-cognitive behavioral traits. we used a multi-access box (mab) paradigm to measure repeated innovation, the number of unique innovations learned across trials, by 10 captive spotted hyenas (crocuta crocuta). spotted hyenas are highly innovative in captivity and also display striking ... | 2018 | 29511943 |
| lions, hyenas and mobs (oh my!). | understanding the factors that facilitate the emergence of cooperation among organisms is central to the study of social evolution. spotted hyenas crocuta crocuta frequently cooperate to mob lions panthera leo, approaching the lions as a tightknit group while vocalizing loudly in an attempt to overwhelm them and drive them away. whereas cooperative mobbing behavior has been well documented in birds and some mammals, to our knowledge it has never been described during interactions between 2 apex ... | 2017 | 29491990 |
| numerical assessment in the wild: insights from social carnivores. | playback experiments have proved to be a useful tool to investigate the extent to which wild animals understand numerical concepts and the factors that play into their decisions to respond to different numbers of vocalizing conspecifics. in particular, playback experiments have broadened our understanding of the cognitive abilities of historically understudied species that are challenging to test in the traditional laboratory, such as members of the order carnivora. additionally, playback experi ... | 2017 | 29292356 |
| the hunters or the hunters: human and hyena prey choice divergence in the late pleistocene levant. | hunting preferences reveal a great deal about the life of paleolithic humans, and may reflect changes in human demography, technology, and adaptations to changing environments. however, the effects of hunting preferences and environmental availability are often conflated, stressing the need for comparisons to other predators that exploited the same environment. manot cave (israel), preserved rich early upper paleolithic (46-33 ka) human occupations, along with repeated spotted hyena (crocuta cro ... | 2019 | 30850235 |
| rabies of canid biotype in wild dog (lycaon pictus) and spotted hyaena (crocuta crocuta) in madikwe game reserve, south africa in 2014-2015: diagnosis, possible origins and implications for control. | both domestic and wild carnivore species are commonly diagnosed with rabies virus (rabv) infection in south africa. although the majority of confirmed rabies cases in wild carnivore species are reported from the yellow mongoose (cynictis penicillata), the rest are from other wild carnivores including the highly endangered wild dog (lycaon pictus). lyssavirus infection was confirmed in two wild dogs and a spotted hyaena (crocuta crocuta) in the madikwe game reserve, north west province in south a ... | 2018 | 29781673 |
| hair cortisol analyses in different mammal species: choosing the wrong assay may lead to erroneous results. | wild animals are faced with a broad range of environmental stressors and research is needed to better understand their effect on populations. hormone analysis based on enzyme immunoassays (eias) can provide valuable information on adrenocortical activity (stress), and assessment of cortisol in hair may allow the quantification of cortisol production. to validate hair hormone analysis, we compared two eias based on antibodies against cortisol-3-cmo-bsa and cortisol-21-hs-bsa for hair glucocortico ... | 2020 | 32153782 |
| spotted hyaenas and the sexual spectrum: reproductive endocrinology and development. | the spotted hyaena (crocuta crocuta) is a unique species, even amongst the hyaenidae. extreme clitoral development in female spotted hyaenas challenges aspects of the accepted framework of sexual differentiation and reproductive function. they lack a vulva and instead urinate, copulate and give birth through a single, long urogenital canal that traverses a clitoris superficially resembling a penis. recent and historical evidence is reviewed to describe our changing understanding of the biology o ... | 2020 | 32755997 |
| innovative problem-solving in wild hyenas is reliable across time and contexts. | individual differences in behavior are the raw material upon which natural selection acts, but despite increasing recognition of the value of considering individual differences in the behavior of wild animals to test evolutionary hypotheses, this approach has only recently become popular for testing cognitive abilities. in order for the intraspecific approach with wild animals to be useful for testing evolutionary hypotheses about cognition, researchers must provide evidence that measures of cog ... | 2020 | 32747691 |
| reproduction within a hierarchical society from a female's perspective. | the reproductive biology of many female mammals is affected by their social environment and their interactions with conspecifics. in mammalian societies structured by linear dominance hierarchies, such as that of the spotted hyena (crocuta crocuta), a female's social rank can have profound effects on both her reproductive success and her longevity. in this species, social rank determines priority of access to food, which is the resource limiting reproduction. due largely to rank-related variatio ... | 2020 | 32667986 |
| early-life relationships matter: social position during early life predicts fitness among female spotted hyenas. | how social development in early-life affects fitness remains poorly understood. though there is growing evidence that early-life relationships can affect fitness, little research has investigated how social positions develop or whether there are particularly important periods for social position development in an animal's life history. in long-lived species in particular, understanding the lasting consequences of early-life social environments requires detailed, long-term datasets. here we used ... | 2020 | 32578217 |
| sexual dimorphism of perineal muscles and motoneurons in spotted hyenas. | female spotted hyenas are known for their male-like genitalia, high levels of aggression, and dominance over males, characteristics which are attributed to exposure to elevated levels of testosterone in utero. although the nervous system of spotted hyenas has not previously been examined, one might predict that neural systems which are sexually dimorphic in other mammals would be monomorphic in this species. spinal motoneurons which innervate muscles associated with the phallus are located in on ... | 1996 | 8915834 |
| sexual differentiation of the female spotted hyena. one of nature's experiments. | | 1992 | 1456636 |
| fatal sibling aggression, precocial development, and androgens in neonatal spotted hyenas. | fatal neonatal sibling aggression is common in predatory birds but has not been previously reported in wild mammals. spotted hyena females are strongly masculinized, both anatomically and behaviorally, apparently by high levels of androgens during ontogeny. neonates display elevated androgen levels, precocial motor development, and fully erupted front teeth. litters are usually twins, and siblings fight violently at birth, apparently leading to the death of one sibling in same-sex litters, where ... | 1991 | 2024122 |
| the interhemal membrane of the spotted hyena: an immunohistochemical reappraisal. | on the basis of specific immunohistochemical staining for vimentin and cytokeratin, we conclude that in the mature placenta of the spotted hyena the interhemal membrane is haemomonochorial rather than endotheliochorial, as in other carnivores. we concur that the intrasyncytial laminae are remnants of the maternal endothelial basal lamina. | 2006 | 1695374 |
| small mammal diversity of mt. kenya based on carnivore fecal and surface bone remains. | ecological dynamics and faunal diversity documentation is normally conducted by direct observation and trapping of live animals. however, surveys of carnivore scat prey and surface bone remains, which are relatively inexpensive, can provide complementary data that expand carnivore diet breadth and may improve accuracy regarding inferences of the ecological dynamics of a given ecosystem. we used this inexpensive method to document species diversity variation with elevation on the leeward (sirimon ... | 2019 | 30348933 |
| in what sense are dogs special? canine cognition in comparative context. | the great increase in the study of dog cognition in the current century has yielded insights into canine cognition in a variety of domains. in this review, we seek to place our enhanced understanding of canine cognition into context. we argue that in order to assess dog cognition, we need to regard dogs from three different perspectives: phylogenetically, as carnivoran and specifically a canid; ecologically, as social, cursorial hunters; and anthropogenically, as a domestic animal. a principled ... | 2018 | 30251104 |
| hyena paleogenomes reveal a complex evolutionary history of cross-continental gene flow between spotted and cave hyena. | the genus crocuta (african spotted and eurasian cave hyenas) includes several closely related extinct and extant lineages. the relationships among these lineages, however, are contentious. through the generation of population-level paleogenomes from late pleistocene eurasian cave hyena and genomes from modern african spotted hyena, we reveal the cross-continental evolutionary relationships between these enigmatic hyena lineages. we find a deep divergence (~2.5 ma) between african and eurasian cr ... | 2020 | 32201717 |
| juvenile rank acquisition is associated with fitness independent of adult rank. | social rank is a significant determinant of fitness in a variety of species. the importance of social rank suggests that the process by which juveniles come to establish their position in the social hierarchy is a critical component of development. here, we use the highly predictable process of rank acquisition in spotted hyenas to study the consequences of variation in rank acquisition in early life. in spotted hyenas, rank is 'inherited' through a learning process called 'maternal rank inherit ... | 2020 | 32126950 |
| exposure to toxoplasma gondii in zoo animals in spain. | a serosurvey was performed to assess exposure to toxoplasma gondii in zoo animals in spain and to determine the dynamics of seropositivity in some zoo species over time. sera from 393 zoo animals belonging to 91 species were collected in eight zoos in spain between 2007 and 2019. additionally, 39 of the 393 animals from five of the analyzed zoos were longitudinally sampled during the same study period. antibodies to t. gondii were detected in 165 (42.0 %; ci95 %: 37.1-46.9) of 393 animals by the ... | 2020 | 32109781 |
| age, gender, and feeding environment influence fecal microbial diversity in spotted hyenas (crocuta crocuta). | fecal microbes play an important role in the survival and health of wild animals. spotted hyena (crocuta crocuta) is one of the representative carnivores in africa. in this study, we examined the fecal microflora of spotted hyena by conducting high-throughput sequencing of the fecal microbial 16s rrna gene v3-v4 high mutation region. the effects of age, sex, and feeding environment on the fecal microbiota of spotted hyenas were determined. the results showed that the core bacteria phyla of spott ... | 2020 | 32052138 |
| body site-specific microbiota reflect sex and age-class among wild spotted hyenas. | host-associated microbial communities, henceforth 'microbiota', can affect the physiology and behavior of their hosts. in mammals, host ecological, social and environmental variables are associated with variation in microbial communities. within individuals in a given mammalian species, the microbiota also partitions by body site. here, we build on this work and sequence the bacterial 16s rrna gene to profile the microbiota at six distinct body sites (ear, nasal and oral cavities, prepuce, rectu ... | 2020 | 31926016 |
| identity of spirometra theileri from a leopard (panthera pardus) and spotted hyena (crocuta crocuta) in tanzania. | in the present study, a spirometra species of tanzania origin obtained from an african leopard (panthera pardus) and spotted hyena (crocuta crocuta) was identified based on molecular analysis of cytochrome c oxidase i (cox1) and nadh dehydrogenase subunit i (nad1) as well as by morphological observations of an adult tapeworm. one strobila and several segments of a spirometra species were obtained from the intestine of an african male leopard (panthera pardus) and spotted hyena (crocuta crocuta) ... | 2019 | 31914517 |
| parasite infections in a social carnivore: evidence of their fitness consequences and factors modulating infection load. | there are substantial individual differences in parasite composition and infection load in wildlife populations. few studies have investigated the factors shaping this heterogeneity in large wild mammals or the impact of parasite infections on darwinian fitness, particularly in juveniles. a host's parasite composition and infection load can be shaped by factors that determine contact with infective parasite stages and those that determine the host's resistance to infection, such as abiotic and s ... | 2019 | 31410280 |
| sex determining region y (sry) sequencing and non-invasive molecular sexing in three wild species: brown (parahyaena brunnea) and spotted (crocuta crocuta) hyenas and aardvark (orycteropus afer). | non-invasive molecular sexing methods are useful in captive breeding programs and field studies; these methods enable sex identification without immobilisation or stressful handling of animals. we developed a method enabling fast and reliable sex identification in three species with limited external sexual dimorphism: the brown and spotted hyenas and the aardvark. we used the sex determining region y (sry) gene as the male-specific sequence and the c-myc gene, highly conserved among mammals, as ... | 2019 | 30971330 |
| social alliances improve rank and fitness in convention-based societies. | social hierarchies are widespread in human and animal societies, and an individual's position in its hierarchy affects both its access to resources and its fitness. hierarchies are traditionally thought of in terms of variation in individual ability to win fights, but many are structured around arbitrary conventions like nepotistic inheritance rather than such traits as physical strength or weapon size. these convention-based societies are perplexing because position in the hierarchy appears to ... | 2019 | 30858321 |
| brain and body size relations among spotted hyenas (crocuta crocuta). | the relationship between brain size and body size across species "from mouse to elephant" is described by a function of positive slope. almost uniformly, the relationship between brain size and body size within a species has a positive slope, though this is less steep than across species. the spotted hyena, crocuta crocuta, differs from most other mammals in a number of ways including the fact that, on average, adult females weigh more than adult males and occasionally display greater body lengt ... | 2018 | 30415261 |
| the virus-host interface: molecular interactions of alphacoronavirus-1 variants from wild and domestic hosts with mammalian aminopeptidase n. | the alphacoronavirus-1 species include viruses that infect numerous mammalian species. to better understand the wide host range of these viruses, better knowledge on the molecular determinants of virus-host cell entry mechanisms in wildlife hosts is essential. we investigated alphacoronavirus-1 infection in carnivores using long-term data on serengeti spotted hyenas (crocuta crocuta) and molecular analyses guided by the tertiary structure of the viral spike (s) attachment protein's interface wit ... | 2021 | 33786949 |
| social support drives female dominance in the spotted hyaena. | identifying how dominance within and between the sexes is established is pivotal to understanding sexual selection and sexual conflict. in many species, members of one sex dominate those of the other in one-on-one interactions. whether this results from a disparity in intrinsic attributes, such as strength and aggressiveness, or in extrinsic factors, such as social support, is currently unknown. we assessed the effects of both mechanisms on dominance in the spotted hyaena (crocuta crocuta), a sp ... | 2019 | 30455441 |