Search

Cranial material of Pachycrocuta brevirostris from the late Early Pleistocene site of Nogaisk is the first record of this species in Ukraine. This large hyena was a representative of the Tamanian faunal complex and a single specialised scavenger in these faunas. The revisited European records list of P. brevirostris documented the presence of this species in 101 sites, dated in the range of 3.5–0.4 Ma. This species first disappeared in Africa, survived in Europe until ca. 0.8–0.7 Ma, and its last, relict occurrence was known from south-eastern Asia. The main reason of extinction of P. brevirostris probably was the competition with Crocuta crocuta. The cave hyena was smaller, but its teeth were proportionally larger to the body size, better adapted to crushing bones and slicing meat, and could also hunt united in larger groups.

Studies of modern carnivore accumulations of bone (i.e., neo-taphonomy) are crucial for interpreting fossil accumulations in the archaeological and paleontological records. Yet, studies in arid regions have been limited in both number and detailed taphonomic data, prohibiting our understanding of carnivore bone-accumulating and -modifying behavior in dry regions. Here, we present a taphonomic analysis of an impressive carnivore-accumulated bone assemblage from the Umm Jirsan lava tube in the Harrat Khaybar region, Saudi Arabia. The size and composition of the bone accumulation, as well as the presence of hyena skeletal remains and coprolites, suggest that the assemblage was primarily accumulated by striped hyena (Hyaena hyaena). Our findings (1) identify potentially useful criteria for distinguishing between accumulations generated by different species of hyenas; (2) emphasize the need for neo-taphonomic studies for capturing the full variation in carnivore bone-accumulating and modifying behavior; (3) suggest that under the right settings, striped hyena accumulations can serve as good proxies for (paleo)ecology and livestock practices; and (4) highlight the potential for future research at Umm Jirsan, as well as at the numerous nearby lava tube systems. We encourage continued neo-taphonomic efforts in regions important in human prehistory, particularly in arid zones, which have received little research attention. Introduction - Study area Material and methods Results - Species representation - Skeletal part representation - Bone surface modifications - Bone fragmentation and fracture patterns - Mortality profiles Discussion - Accumulator(s) of the Umm Jirsan assemblage - Striped hyena feeding behavior at Umm Jirsan - Implications for prehistory and paleoecology Conclusion

A hybrid spotted hyena optimizer (SHO) based on lateral inhibition (LI) is proposed, it has been applied to solve complication image matching problems. Lateral inhibition mechanism is applied for image pre-process to make intensity gradient in the image contrast enhanced and has the ability to enhance the characters of image, which is able to improve the accuracy of image matching. SHO is inspired from the behavior of social relationship and collaborative of spotted hyenas. This algorithm search for the global optimum mainly through four steps: prey, encircling, attacking prey, and searching prey. In the algorithm, the computation of search location is drastically reduced by incorporating of fitness calculation strategy for solving the real-life optimization problems. The proposed LI-SHO method for image matching mixed together the advantages of SHO and lateral inhibition mechanism. The experiment shows that the proposed algorithm based on lateral inhibition is more effective and feasible in image matching than the other comparing algorithm.

Spotted hyena optimizer (SHO) is a recently developed metaheuristic technique that mimics the hunting behavior of the spotted hyenas. However, it does not provide optimal solution for discrete problems. Therefore, a novel binary version of Spotted Hyena Optimizer is proposed in this paper. The binary version of SHO can deal with discrete optimization problems. In the proposed algorithm, tangent hyperbolic function is utilized to squash the continuous position and then these values are used to update the position of spotted hyenas. The prey searching, encircling, and attacking are three main steps of binary spotted hyena optimizer. The proposed algorithm has been compared with six well-known metaheuristic techniques over 29 benchmark test functions. The effects of convergence, scalability, and control parameters have been investigated. The statistical significance of the proposed approach has also been examined through ANOVA test. The proposed approach is also applied on feature selection domain. The performance of proposed approach has been compared with four well-known metaheuristic techniques over eleven UCI repository datasets. The experimental results reveal that the proposed approach is able to search the optimal feature set than the others.

Small, enclosed reserves are now common across Africa, and their conservation importance as wildlife refuges is increasingly acknowledged. Whilst such reserves represent areas safe from human persecution, they can also become threats themselves when the natural processes of emigration and immigration are prohibited. As a result, wildlife populations residing in enclosed reserves require careful management to safeguard their long-term persistence. As successful conservation management relies on precise population estimates, we estimated brown hyena density within a 180-km2 enclosed reserve in north-central Namibia. Using camera trapping methods in combination with spatially explicit capture-recapture (SECR) models, brown hyena density was estimated at 24.01 brown hyenas/100 km2 (± 3.47, 95% CI’s 18.12–31.81), the highest recorded to date for the species. The high density is attributed to the relatively high density of leopard within the reserve, which may facilitate brown hyenas by providing access to the large herbivore biomass through kleptoparasitism, coupled with protection from human persecution. Results highlight the potential for enclosed reserves to host high-density populations of a persecuted large carnivore and show that, despite their often small size, such systems can aid conservation efforts. However, such results suggest reserve managers will be increasingly faced with the dilemma of dealing with surplus individuals when populations exceed carrying capacity. Therefore, the development of methods estimating carrying capacity for scavenging species, along with creating meta-population management schemes for all large carnivore species are essential next steps for conservation in Africa.

The striped hyena (Hyaena hyaena) is one of the largest carnivores within forest and grassland ecosystems across Africa and Asia and is currently threatened throughout its range. In this short report, we studied hyena presence between 1995 and 2018 in Nepal, via literature and field questionnaire surveys. Our results indicate that hyena distribution has significantly decreased in recent years, especially in areas outside National Parks, and is currently confined to the lowlands and hill areas of western and central Nepal. Although hyenas within National Parks have been least affected, the remaining population outside protected areas would be challenging for future conservation, without the implementation of a focused action plan incorporating community-based approaches.

Communal marking sites, or latrines, appear to play an important role in intraspecific communication and social dynamics in a wide range of mammal species. The spatial distribution of latrines can provide clues to their function and has been well documented in a number of species. Latrine use may vary considerably through time, however, and a more comprehensive approach to their study that considers spatial and seasonal patterns of use is required to understand more fully the costs and benefits of latrine use, and hence their adaptive significance. This study investigated spatial and seasonal patterns of latrine use by spotted hyena (Crocuta crocuta) in northern Botswana, examining their potential role in resource defense. Latrine characteristics and hyena activity were monitored to test the influence of season and location (relative to clan territories and roads) on latrine use. We conducted monthly scat counts (at 78 latrines) and continuously recorded hyena visitation (to 50 latrines) in five clan home ranges, demonstrating clear seasonal patterns in latrine use. Latrines were smaller in the wet season (November-March), resulting from fewer visits by hyenas, reduced scat accumulation, and the seasonal activity of coprophagous beetles. We speculate that such a seasonal pattern may be driven by reduced competition for food during the wet season. Latrines located within core clan areas were no larger or more frequently used than those in home-range boundary areas, but hyenas did preferentially place latrines alongside roads and were more likely to reuse road-side latrines in subsequent years. This pattern was not due to observer detection bias and adds to the growing body of literature on the impact that roads and other anthropogenic features have on the communication and movement ecology of wild animals. Although most mammals use communal marking sites, very little is known about their function and detailed patterns of use in many species. We investigated latrine use in spotted hyena (Crocuta crocuta) and describe spatial and temporal marking patterns that are consistent with optimizing scent longevity and detection. Spatially, hyenas preferentially located latrines along the edge of man-made vehicle tracks, which may increase signal detection and transmission. Seasonal marking patterns suggest that hyenas optimize their communication by concentrating activity in the dry season, thereby avoiding the disruptive effects of coprophagous dung beetles and rain, and focusing activity during periods when food resources are expected to be scarcer. These results demonstrate seasonal and spatial optimization of communication, including in response to novel anthropogenic features in the environment such as roads, advancing our understanding of communication strategies in mammals more broadly.

Taphonomic studies, along with modern analogs arisen from experimentation, have been developed to discern the agents responsible for bone accumulations. A special focus has been given to carnivores, which may produce bone accumulations or interact with hominins by ravaging bones from archaeological sites. Although a great effort has been made to study several carnivore species (namely, felids, hyenids and canids), a limited knowledge concerning some scavenging species such as the striped hyena (Hyaena hyaena) remains. The present study shows the results of an experiment carried out at Olduvai Gorge (Ngorongoro Conservation Area, Tanzania) which aimed at assessing the impact of striped hyenas on a goat carcass. After human butchering, the goat carcass was deposited in an area near the FLK North site, where nocturnal carnivores are very active. The orientation and arrangement of the bone assemblage were documented daily and recorded with the aid of photogrammetric techniques. The behaviour of the carnivores acting on the carcasses was recorded by a motion camera picture. The only carnivore involved in the modification of the bone assemblage was the striped hyena. The results show that the post-ravaging behaviour of this species is similar to that previously documented for the spotted hyena (Crocuta crocuta). Oddly, after one night of carnivore ravaging, the experimental sample showed anisotropy. The carnivore ravaging carried out by the striped hyena modified the orientation pattern of the simulated archaeological site. Thus, carnivore ravaging may also impact the spatial orientation pattern of archaeological sites.

Large carnivore populations are declining worldwide due to direct and indirect conflicts with humans. Protected areas are critical for conserving large carnivores, but increasing human-wildlife conflict, tourism, and human population growth near these sanctuaries may have negative effects on the carnivores within sanctuary borders. Our goals were to investigate how anthropogenic disturbance along the edge of the Masai Mara National Reserve, Kenya, influences the demography and space-use of two large carnivore species that engage in intense interspecific competition. Here we document, in one disturbed region of the Reserve, a rapid increase in the population size of one large predator, the spotted hyena (Crocuta crocuta), but a striking concurrent decline in numbers of another, the African lion (Panthera leo). Anthropogenic disturbances negatively affected lion populations, and decreasing lion numbers appear to have a positive effect on hyena populations, indicated here by an increase in juvenile survivorship. We also saw an increase in the number of livestock consumed by hyenas. Our results suggest human population growth and indirect effects of human activity along Reserve boundaries may be effecting a trophic cascade inside the Reserve itself. These results indicate both top-down and bottom-up processes are causing a shift in the carnivore community, and a major disruption of guild structure, inside the boundaries of one of the most spectacular protected areas in Africa.

Striped hyena (Hyaena hyaena) is a near-threatened large carnivore known to occur in arid and semi-arid landscapes in many parts of the world. Its population is declining globally and ecological information is required urgently to meet their conservation needs. We studied the diet pattern of the striped hyena in the semi-arid Gir National Park and Sanctuary (GNPS), western India. Prey items eaten by the striped hyena were identified from scats. Around 44.4% scats represented single to three mammalian preys while 55.6% of them represented four preys to seven preys. A variety of food items were identified including mammals, birds, insects and vegetable matters. Scats analysis showed that 63.91% diet of striped hyena was contributed by wild prey items, 20.94% by domestic prey and 3.31% by birds, whereas vegetable and insects contributed 9.92% and 1.93%, respectively. Diet diversity of the striped hyena computed by the Shannon-Weiner Index (H) was found to be 2.64. The presence of domestic mammals in the scat remains implied that the striped hyena might frequently visit human habitation in search for food and hence, a potential conflict between human and wildlife might arise. Reducing the dependence of hyena on domestic livestock is a challenge to ensure the survival of striped hyena outside the protected area.

The internal cranial morphology of the bone-cracking hyena Pliocrocuta perrieri (Carnivora, Hyaenidae) is described based on three crania from the late Pliocene and early Pleistocene of the Iberian Peninsula. The shape and size of the inner cranial cavities (with emphasis on encephalization and relative regional brain volumes) are compared with those of extant hyaenids with the aid of computed tomography techniques—which had not been previously used to study the brain morphology of any extinct bone-cracking hyena. Our results indicate that the frontal sinuses of P. perrieri are caudally extended and overlap the brain cavity, as in other extinct and extant bone-cracking hyaenids. In turn, the brain morphology and sulcal pattern of P. perrieri are more similar to those of Hyaena hyaena and Parahyaena brunnea than to those of Crocuta crocuta among extant bone-cracking hyaenids. Our results further indicate that Pliocrocuta is clearly less encephalized than the highly-social Crocuta, and displays an anterior cerebrum relatively smaller than in all extant bone-cracking hyenas (indicating the possession of a poorly-developed frontal cortex). These facts might suggest that P. perrieri possessed less developed cognitive abilities than Crocuta for processing the information associated with complex social behaviors.

Social development is crucial in the ontogeny of animals living in complex societies and has lasting consequences in adulthood. Spotted hyenas (Crocuta crocuta) live in fission-fusion societies as complex as those of cercopithecine primates. The social positions adult hyenas hold within their groups are complex and varied, but little is known about how those positons emerge and change over the course of development. Using social network analysis (SNA), we tested predictions of hypotheses suggesting that sex and dominance status affect the social network positions of young hyenas across three stages of ontogeny: (1) while living at the communal den, (2) den independent but pre-reproductive, and (3) early adulthood. By examining rates at which hyenas were found alone and their association networks, aggression networks, and affiliation networks, we observed striking changes in individuals’ network positions across ontogeny, as well as pronounced sex differences. With the exception of rates at which individuals were found alone, which increased over ontogeny, most social network position metrics decreased greatly from infancy to adulthood. However, females showed considerably more rank-related variation in this trajectory than did males. Overall, social rank had stronger effects on the development of social network positions in females than males. Thus, females and males have different social development trajectories that appear to prepare them for their different respective futures of integrating into their natal clan or dispersing to a new one. Social development is difficult to study, particularly in long-lived gregarious mammals, so little is known about the variables shaping the emergence during ontogeny of social roles played by adults. We used social network analysis to investigate how sex and rank affect the social positions of maturing spotted hyenas as their positions change across ontogenetic development. Females develop more complex social positions than males early in life, with strategies that vary with their dominance status. Although males are just as well connected to group-mates as females when they are cubs, they generally disengage from the natal clan as they mature; males clearly do not disperse because they are aggressively expelled from their natal group. Our data suggest for the first time that social development appears to prepare females and males for their alternative futures of philopatry or dispersal.

Large predators in West Africa are threatened with extinction mainly by direct and indirect effects of human activities. Within this context, intraguild competition can limit populations of some species and even play a role in extinction. In this study, we used camera trapping to assess the spatial and temporal patterns of niche partitioning between the African lion Panthera leo leo and the spotted hyena Crocuta crocuta in Pendjari Biosphere Reserve, Benin. We found that these predators are more nocturnal in the hunting zone than in the national park of the biosphere reserve. The temporal overlap between lion and hyena was high in the national park (Pianka overlap index 0.88) and low in the hunting zones (0.39). The spatial overlap was low (0.40 in the national park and 0.38 in the hunting zones). The two predators were distributed independently in the national park, but showed significant positive association (co-occurrence) in the hunting zones. We suggest that anthropogenic activities leading to depletion of predators and their prey limit lion and hyena distribution in the hunting zones to some safety areas which are strongly selected by both predators. We recommend to significantly improve conservation efforts in the hunting zones of Pendjari Biosphere Reserve and to expand research of lion-hyena intraguild relationships to improve predator survival in West Africa.

Though retaliatory lion (Panthera leo) killing as a result of livestock predation in the Maasai group ranches between the Tsavo NPs and Amboseli is remarkably high, other wildlife species are known to kill livestock. Surprisingly, lions suffer the most from retaliatory killing by the Maasai community for killing livestock. The extent of livestock predation by lions in comparison to other species is unknown. This study was carried out in the Olgulului group ranch (OGR) located adjacent to Amboseli National Park in June 2009. The cost of livestock killed by each of these species including lion, hyena (Crocuta crocuta), cheetah (Acynonyx jubatus), leopard (Panthera pardus), olive baboon (Papio cynocephalus), black-backed jackal (Canis mesomelas), and African elephant (Loxodonta africana) was analyzed. Questionnaires, focus group discussions, and key informant interviews with officials from OGR, Kenya Wildlife Service (KWS), and compensation scheme organizations were the methods used to collect information. Cluster and systematic sampling techniques were used to select a sample of 199 respondents from OGR. Lions were blamed for 40.5% (US$ 374,603) of the value of livestock lost to wildlife. The costs of livestock lost to hyenas and lions were not significantly different (q = 0.24, p = 0.968). Although hyenas killed more livestock compared to lions, the economic damage between the two was not significantly different because lions attacked cattle which had high economic value. Conservation of lions will be increasingly difficult if the current levels of predation are not reduced to economically and socially acceptable levels.

We used camera trapping in conjunction with a spatial explicit capture–recapture model to estimate striped hyena (Hyaena hyaena) density and occupancy models to investigate factors affecting striped hyena detection probabilities in Ranthambhore Tiger Reserve (RTR), Rajasthan, India. A sampling effort of 4,450 trap days/nights over 75 days yield 68 photo captures of 21 unique striped hyenas (based on individual markings and visual identification); the estimated striped hyena density was 5.49 ± 1.27 individuals/100 km2. Results of our occupancy model suggested that a rugged terrain is an important factor that influences striped hyena detection probability. Correlation with striped hyena detection with human settlement provides evidence of social tolerance of striped hyena towards humans, and more occurrence of resources allowed coexistence of hyena in a human-dominated landscape. This elasticity (inhabited areas close to humans) demonstrated by striped hyenas is an exception among carnivore communities living in this semi-arid habitat.

The scavenging activities of hyenas and lions at the Neumark-Nord Lake 1 (Central Germany) site on straight tusk elephant carcasses is commonly documented by slight bone damages and initial skeleton partitioning. Canine bite marks are found at several joints of elephant long bones, as well as on the vertebrae and skulls. Deep bite and scratch marks from 5 to 7 mm in width made by large carnivore canine teeth (Panthera leo spelaea, Crocuta crocuta spelaea) on the ventral vertebral columns and pelvises of two Palaeoloxodon antiquus straight-tusked elephant skeletons suggest that the intestines and inner organs were consumed by both large lion/hyena predators as is commonly observed when modern African lions and spotted hyenas feed on contemporary elephant carcasses. A scavenging strategy can be demonstrated using 24 partly preserved Palaeoloxodon skeletons, where Ice Age spotted hyenas appear to be the main scavenger (95 %) and sole skeleton decompositor such as bone destructor. While Crocuta may feed anywhere on an elephant carcass, they are known to specialize to eat the complete feet, whereas scavenging from the anus into the body cavity (intestine/internal organ feeding) is more typical of lions. Shallow water at Neumark-Nord Lake 1 prevented hyenas from completely scavenging elephants; thus, bone damage at this site was constrained to initial stages of destruction and final carcass partitioning by high water stands and floods.

We surveyed density and abundance of spotted hyena (Crocuta crocuta) in the highly degraded and prey depleted Wukro district, northern Ethiopia, with a human population density of 98 persons per square kilometer. A total of 117 spotted hyenas responded to callups, giving a hyena density of 52 hyenas per 100 km2 or a total population of 535 hyenas in the district. We quantified the economic impact of spotted hyena predation on livestock using semi structured interviews with randomly selected households. Respondents indicated a total loss of 203 domestic animals to hyena depredation over the past five years. Average annual depredation per household was 0.13 livestock worth US$ 6.1. The diet of spotted hyenas was assessed in three sub-districts by scat analysis and showed 99% prey items of domestic origin, only three of 211 scat contained hair of Ethiopian hare (Lepus fagani) and porcupine (Hystrix cristata). We conclude that hyenas in northern Ethiopia live at high density and eat almost exclusively anthropogenic food and are not dependent on conservation areas.

In the history of zoology the English anatomist Morrison Watson (1845–1885) is considered to be the discoverer of the masculinized sexual organs of the spotted hyena. Beginning in 1877, Watson had published a series of anatomical studies on the spotted hyena (Watson, 1877, 1878, 1881, Watson and Young, 1879), in which he, in which he for the first time made public the anatomical peculiarities of the female spotted hyena’s genitalia. This scientific achievement is well documented. But now we can also state that a hundred years before Watson the Dutch amateur zoologist Robert Jacob Gordon (1743–1795), while serving in the Scots Brigades at the Cape of Good Hope, had already made the same discovery and merely unfortunate personal circumstances prevented publication. During his stay at the Cape, Gordon had studied spotted hyenas intensively and recorded his observations in accurate drawings and comments. These drawings have been preserved as part of a large collection of animal drawings entitled Gordon Atlas. With his discovery, Gordon actually was the first to provide empirical evidence of a “curious and inexplicable case of dimorphism” (Darwin on a beetle) in mammalians, long before Etienne Geoffrey Saint-Hilaire (Cours de l’histoire naturelle des mammiferes, 1829) started examining masculinized sexual organs in the mole or Darwin recognized the importance of sexual dimorphism (Descent of Man, 1871). In this paper we reproduce for the first time all hyena drawings from the Gordon Atlas, including Gordon’s handwritten notes in the margins in the original Dutch and in translation. Additionally, we briefly delineate the knowledge about the South African spotted hyena in Gordon’s time and indicate that we doubt Watson’s explanation for the age-old confusion about the hyena.

We present osteological evidence that a rhinocerotid skull belonging to a female Chilotherium wimani was bitten by a giant percrocutid, Dinocrocuta gigantea. Aided by comparative evidence of black rhino (Diceros bicornis) predation by extant spotted hyenas Crocuta crocuta, we interpret the healed wound on the C. wimani female as an injury incurred by the late Miocene D. gigantea. The hunting paleoecology of the giant percrocutid D. gigantea has long been speculated, but thus far no clear evidence has been discovered to point to the predatory habits of this carnivore. The present specimen of C. wimani provides evidence to indicate that the giant percrocutid shared similarities in predatory behavior to the modern spotted hyena: it was an active hunter in spite of the specialized bone-cracking craniodental morphology which imparted superb capability for processing bone.

Vitamin A toxicity in the infant, which now occurs rarely from dietary overdosage, was recognized in the 1940s as painful periostitis with rare progression to premature closure of the lower limb epiphyses. Decades later, most cases of vitamin A-induced premature epiphyseal closure (physeal obliteration) occur in pediatric dermatologic patients given vitamin A analogues. This phenomenon resembles a strange disease discovered in more recent years in calves with closed epiphyses of the hind limbs, known as hyena disease. This was a mystery until proved to be caused by vitamin A toxicity from enriched grain that causes the calves to have short hind limbs that resemble those of a hyena and gait disturbance. This historical review links the human and veterinary literature in terms of vitamin A-induced epiphyseal closure using a case report format of a 16-month-old human infant with closed knee epiphyses and gait disturbance that is reminiscent of hyena disease seen in calves.

In the Serengeti National Park, Tanzania, large fluctuations of prey abundance alters the frequency at which spotted hyena (Crocuta crocuta) cubs are nursed and thus the total level of maternal input available to them. Maternal input is high when mothers feed on high densities of locally available migratory herbivores and low when mothers travel up to 70 km to forage. Using data from 19 cub cohorts on the incidence of siblicide (from monitoring the survival of 609 cubs in twin litters) and cub growth rates (from 195 cubs in twin litters) as a measure of maternal input, we demonstrate that the incidence of siblicide increased as average cohort growth rate declined. In total, there were 37 siblicides in 384 litters (9% of litters). When both cubs were alive, total maternal input in siblicidal litters was significantly lower than in non-siblicidal litters and the mean share of the dominant sib of 64.6% was significantly higher than the mean of 52.1% for dominant sibs of non-siblicidal litters. After siblicide, growth rates of siblicide victors substantially increased, demonstrating that mothers did not reduce maternal input after litter reduction. As a result, siblicide victors achieved a long-term growth rate similar to that of singletons and thus significantly increased their expected survival. We conclude that in spotted hyenas, high maternal input in lactation has favoured the evolution of facultative siblicide in populations inhabiting areas with low or fluctuating food resources.

Among spotted hyenas, Crocuta crocuta, neonatal aggression in twins is a well-known phenomenon and serves to establish intra-litter dominance soon after birth. As the stronger more aggressive cub presumably attains dominance over its twin, intra-litter dominance presents mothers with an ideal opportunity to assess individual cub fitness and, thereafter, to selectively favor one cub over the other. This study quantified maternal response to sibling conflict in 26 sets of twins born to 16 wild-living females to determine whether mothers of different social ranks exhibited favoritism towards sons or daughters, or in the case of same-sex twins, the dominant or subordinate cub. Maternal response to sibling conflict did not vary with litter sex composition, suggesting that mothers do not favor offspring of one sex over the other. All mothers intervened when their cubs fought and sometimes punished their cubs. Higher-ranking mothers more often punished both cubs, while lower-ranking mothers were more selective and punished the dominant cub. Where sibling aggression was most extreme, rather than favor the dominant sibling, mothers of all ranks made concessions to the subordinate cub that included procuring private nursing bouts for the subordinate and temporarily housing twins in separate dens, presumably to decrease sibling conflict. These findings represent a complex example of parent–offspring conflict and support both the insurance cub hypothesis and resource tracking hypothesis that mothers endeavor to keep all offspring alive for as long as possible in the event that the dominant sibling dies or that resources provide for the rearing of twins.

When social partners vary in their relative value, individuals should theoretically initiate partnerships with conspecifics of the highest value. Here, we tested this prediction in a wild population of spotted hyenas (Crocuta crocuta). Crocuta live in complex, fission–fusion societies structured by dominance hierarchies in which individuals vary greatly in their value as social companions. Because patterns of association among Crocuta reflect social preferences, we calculated association indices (AIs) to examine how social rank influences intrasexual partner choice among unrelated adults of both sexes. The highest-ranking individuals were generally most gregarious in both sexes. Females associated most often with dominant and adjacent-ranking females. Females joined subgroups based on the presence of particular conspecifics such that subordinates joined focal females at higher rates than did dominants. Dominants benefit from associations with subordinates by enjoying priority of access to resources obtained and defended by multiple group members, but the benefits of these associations to subordinates are unknown. To investigate this, we tested three hypotheses suggesting how subordinates might benefit from rank-related partner choice among unrelated females. We found that subordinates who initiated group formation benefited by gaining social and feeding tolerance from dominants. However, rates at which dominants provided coalitionary support to subordinates did not vary with AIs. Overall, our data resemble those documenting patterns of association among cercopithecine primates. We consider our results in light of optimal reproductive skew theory, Seyfarth’s rank attractiveness model, and biological market theory. Our data are more consistent with the predictions of Seyfarth’s model and of biological market theory than with those of skew theory.

Avian models of facultative siblicide predict that rates of sibling aggression and the incidence of siblicide should be lower in prey-rich than prey-poor environments, and that siblicide should only occur when fitness benefits outweigh costs. We tested these predictions by comparing data from spotted hyena (Crocuta crocuta) twin litters in the Ngorongoro Crater, Tanzania, a habitat with a high density of resident prey (176 animals/km2) with similar data from the adjacent Serengeti National Park where density of resident prey is low (3.3 animals/km2). As predicted, rates of sibling aggression in Crater twin litters were substantially lower than those among twin siblings in the Serengeti. There was no evidence of siblicide in the Crater, in contrast to the Serengeti, where facultative siblicide occurs frequently. The growth rate of Crater cubs in singleton litters was similar to that of cubs in twin litters, whereas the growth rate of Serengeti singletons was higher than that of cubs in twin litters. Thus despotic behavior by dominant Crater cubs was unlikely to provide fitness benefits, while dominant Serengeti cubs that eliminated their sibling benefited from increased growth and enhanced survival. Previous studies have demonstrated biases in the sex-composition of hyena litters due to facultative siblicide. No such biases were apparent in Crater litters. Our results provide strong evidence that levels of sibling aggression in spotted hyenas are adjusted in an adaptive manner, and that siblicide is facultative and resource dependent. Our results do not support the idea of pre-natal manipulation of offspring sex by female spotted hyenas in response to changes in resource abundance.

More than ten thousand bone fragments were recovered from the Lingjing site, Henan Province, during 2005 and 2006. A taphonomic analysis of the faunal remains strongly indicates that hominids have a dominant role in the accumulation and modification of the assemblage. Based on the taphonomic and zooarcheological characteristics of the animal remains, including species richness, mortality patterns, skeletal element profiles, and bone surface-modifications, and on the local ecology, we suggest that the Lingjing site is a Middle Paleolithic kill-butchery site rather than a home base for early humans. The presence of large numbers of stone artifacts may therefore signify a strong sense of planning and farsightedness in the subsistence strategies of early human groups. The Lingjing site is presently the only taphonomically-identified, Middle Paleolithic kill-butchery site known in North China.

We examined patterns of affiliation, association, and aggression to inquire whether spotted hyenas (Crocuta crocuta) can distinguish among various groups of maternal and paternal siblings. If so, and if these animals conform to predictions of kin selection theory, then behavioral interactions among hyenas should vary with relatedness. We also considered familiarity-based recognition and phenotype matching as mechanisms hyenas might use to recognize kin. Patterns of affiliative behavior indicated that hyenas favored full-sibling littermates over half-sibling littermates or any other group of half-siblings. Rates of dyadic aggression generally did not vary with kinship. Hyenas associated more closely with half-sibling littermates than with non-littermate half-siblings, and hyenas affiliated more with maternal half-siblings than with paternal half-siblings, suggesting that familiarity-based cues might mediate discrimination among these sibling classes. In addition, operation of a phenotype-matching mechanism was suggested by the preference hyenas demonstrated during affiliative interactions for full- over half-sibling littermates, and by their lack of preference in these interactions for half-sibling littermates over non-littermate half-siblings. Phenotype matching was also suggested by our observation that paternal half-siblings cooperated more, and fought less, than did non-kin. Our data indicate that hyenas can discriminate among various types of siblings, that their social behavior conforms to predictions of kin selection theory, and that they recognize kin using mechanisms of both familiarity and phenotype matching.

Most studies of foreign compound metabolism have been performed in a restricted number of common laboratory animal species. The examination of animals not commonly found in the laboratory may aid in understanding the effects of environmental chemicals on wild animals and in the search for better animal models for human drug metabolism. We have performed a number of studies in “exotic” animals, such as the lion, civet, genet, hyena, elephant, various bats and reptiles, and this review compares the findings with those in common laboratory animals, to explore the possibility that drug metabolism studies may aid in the zoological classification of animals.

Es wird uber das Vorkommen von grosblasigen Zystizerken im Epiduralraum des Wirbelkanals der Kreuzbeinknochen bei Antilopen der Unterfamilie Alcelaphinae im Serengetigebiet in Tanzania berichtet. Biologische Erwagungen liesen die adulte Form des Parasiten unter den im Dunndarm der Hyane (Crocuta crocuta) schmarotzenden Bandwurmern vermuten. Dabei wurde eine bisher nicht bekannte Taenienart, T. olngojinei sp. nov., gefunden, die in der vorliegenden Arbeit beschrieben wird. Vergleichende Untersuchungen der Rostellumhaken der sich im Kreuzbeinknochen von Antilopen ansiedelnden Zystizerken mit den Rostellumhaken von T. olngojinei sp. nov. lassen erkennen, das es sich bei den Kreuzbeinzystizerken um die Larvenstadien des neuen Bandwurmes handelt.

The Spotted Hyena: a Study of Predation and Social Behaviour. By Hans Kruuk. Pp. xvi + 335. (University of Chicago: Chicago and London, 1972.) £6.75.