Otocyon Research Articles

High-resolution computed tomographic (HRCT) image series from 413 canid and 18 felid skulls

Computed tomography (CT) is a non-invasive, three-dimensional imaging tool used in medical imaging, forensic science, industry and engineering, anthropology, and archaeology. The current study used high-resolution medical CT scanning of 431 animal skulls, including 399 dog skulls from 152 breeds, 14 cat skulls from 9 breeds, 14 skulls from 8 wild canid species (gray wolf, golden jackal, coyote, maned wolf, bush dog, red fox, Fennec fox, bat-eared fox), and 4 skulls from 4 wild felid species (wildcat, leopard, serval, caracal). This comprehensive and unique collection of CT image series of skulls can provide a solid foundation not only for comparative anatomical and evolutionary studies but also for the advancement of veterinary education, virtual surgery planning, and the facilitation of training in sophisticated machine learning methodologies.

Evidence for a host switching in the maintenance of canid rabies variant in two wild carnivore species in the Northern Cape Province, South Africa.

Rabies is a zoonotic infectious disease that causes at least 59 000 human deaths worldwide annually, with 95% of the cases occurring in the developing countries of Asia and Africa. There are two Lyssavirus rabies (RABV) variants circulating in South Africa, notably the canid and mongoose RABV biotypes. The canid RABV biotype is maintained in the domestic dog and two wild carnivore species, the black-backed jackal (Canis mesomelas) and the bat-eared fox (Otocyon megalotis). The yellow mongoose, a member of the Herpestidae family, is a reservoir and vector species for the mongoose RABV biotype. Rabies trends showed an increase in rabiespositive cases in aardwolves between 2011 and 2016 surpassing the bat-eared fox as the most rabies-affected wild carnivore in the Northern Cape Province of South Africa. The aim of the study was to establish the genetic relationships amongst rabies viruses recovered from both the aardwolves and bat-eared foxes. A partial region of the glycoprotein gene and the variable G-L intergenic region of the viral genome were analysed using nucleotide sequences generated from PCR amplicons. The rabies viruses recovered from the aardwolves between the year 2015 and 2017 were 100% nucleotide sequence identical, suggesting a single or common source and possible evidence for a host shift. Furthermore, the phylogenetic reconstruction demonstrated that the rabies viruses obtained from the two wild carnivore species from the Northern Cape Province clustered independently of each o ther with 96% nucleotide sequence identity, suggesting that the aardwolf may be able to maintain the canid RABV variant in this geographical area.

Real power loss reduction by Protist and Otocyon megalotis optimization algorithms

Real power loss reduction by Protist and Otocyon megalotis optimization algorithms

Dietary niche breadth and overlap of four sympatric southern African myrmecophagous mammal species, as inferred from the literature

Five myrmecophagous mammal species occur sympatrically over large parts of southern Africa. Of these, the diets of four species have been studied in sufficient detail to facilitate interspecific comparisons. The diets of the aardvark Orycteropus afer, aardwolf Proteles cristatus, bat-eared fox Otocyon megalotis and Temminck’s pangolin Smutsia temminckii were compared based on the overall prey categories utilised and the proportion of each prey category in their diets, while Meller’s mongoose Rhynchogale melleri had too few data to be assessed. Bat-eared fox fed on the greatest number of prey categories (n = 116) and had the greatest dietary niche breadth (4.71), while aardwolf utilised the fewest prey categories (n = 28) and had the lowest dietary niche breadth (1.19) when analysing the proportion of each prey category in the diet at the genus level. Temminck’s pangolin was the only species that was observed to feed exclusively on ants and termites. The diets of Temminck’s pangolin and aardvark showed a moderate degree of overlap (dietary niche breadth 0.49–0.57), but overlap was low between all other species pairs (0.01–0.26) when analysing the proportion of each prey item in the diet at the genus level. The results suggest that these myrmecophages have low to moderate dietary overlap, which combined with the high abundance of ants and termites and differences in their feeding ecologies, likely reduces interspecific competition.

Blown away? Wind speed and foraging success in an acoustic predator

Foraging animals must contend with fluctuating environmental variables that affect foraging success, including conditions like wind noise, which could diminish the usefulness of particular sensory modes. Although the documented impact of anthropogenic noise on animal behavior has become clear, there is limited research on natural noise and its potential influence on mammalian behavior. We investigated foraging behavior in the myrmecophagous bat-eared fox (Otocyon megalotis), a species known to rely predominantly on hearing for prey detection. For a year, we monitored the foraging behavior of 18 bat-eared foxes from a habituated population in South Africa, amidst varying wind speeds (0–15.5 km/h). In contrast to expectations, foraging rates did not generally decline with increasing wind speed, except for foraging rate outside termite patches in fall. Furthermore, wind speed had little correlation with time spent in patches. In winter, however, we observed an increase in foraging rate with increasing wind speed both within and outside patches. At the observed wind speeds, these acoustically driven insectivores continue to forage effectively despite potentially distracting or masking noises. With anthropogenic noise producing sound across a broader frequency range, it is important to examine the responses of these canids to artificial sources of acoustic disturbance as well.

Innovative problem-solving in a small, wild canid.

Innovation - the ability to solve problems in a novel way - is not only associated with cognitive abilities and relative brain size, but also by noncognitive traits, such as personality and motivation. We used a novel foraging task with three access options to determine how neophobia, exploration, and persistence influence innovation in 12 habituated bat-eared foxes (Otocyon megalotis) in the Kalahari Desert. Bat-eared foxes offer a unique system to understand cognition as they have the smallest relative brain size of measured canids and a specialized, termite-based diet, yet have displayed foraging innovations. Interestingly, most of our individuals solved the task at least once and six individuals solved the task in every trial. Neophobia did not influence success on the first trial, but both exploration and persistence influenced success across all trials. Those individuals that solved the puzzle over multiple trials became faster over time, suggesting that they learned how to open the box more efficiently. We found some variation in the method to open the puzzle box with six individuals solving the puzzle using two methods and one individual using all three methods. This is the first study to show innovation in a novel foraging task in wild bat-eared foxes.

The effect of body size on co‐occurrence patterns within an African carnivore guild

Intraguild interactions among mammalian carnivores are important in shaping carnivore guild composition. Competing species may inhabit different areas and/or being active during different times to reduce the risk of aggressive interactions, but the role of body size in intraguild interactions within carnivore guilds remains largely unknown. We determined spatial and temporal co‐occurrence of small, medium‐sized and large carnivores of the carnivore guild in central Tuli, Botswana: lion Panthera leo, leopard Panthera pardus, spotted hyena Crocuta crocuta, brown hyena Parahyaena brunnea, black‐backed jackal Canis mesomelas, bat‐eared fox Otocyon megalotis, African wildcat Felis sylvestris lybica, African civet Civettictis civetta, honey badger Mellivora capensis and small‐spotted genet Genetta genetta. We used camera trap data over a two‐year period and quantified the degree of temporal and spatial overlap by comparing activity patterns and calculating Pianka's index respectively. Our results showed that temporal overlap in activity between all carnivore species was high, but complete overlap was possibly reduced by differences in peak activity periods. In addition, low to moderate levels of spatial overlap were found between the different carnivore species, supporting the idea that small carnivore species inhabit different areas than large species to reduce the risk of interference competition. Due to the possible strong competition amongst sympatric carnivores there is a need for more knowledge on co‐existence patterns for successful management and conservation of carnivore species, for example when carnivore species are (re)introduced in an area.

Genetic variation between and within two populations of bat-eared foxes (Otocyon megalotis Desmarest, 1822) in South Africa

Information on genetic variation within and among populations is relevant for a broad range of topics in biology. We use a combination of mitochondrial and nuclear microsatellite markers to evaluate genetic variation within and between two populations of bat-eared foxes (Otocyon megalotis Desmarest, 1822) in South Africa. The bat-eared fox is a small canid occurring in southern and eastern Africa. The species is currently not threatened with extinction, but a lack of information on genetic diversity has been identified as a deficit for its future conservation. We observed low to moderate genetic differentiation between the two geographically separated populations, but neither mitochondrial nor nuclear microsatellite markers suggested that there have been dispersal barriers between them. Similar genetic diversity within both populations was contrasted by interpopulational differences in relatedness variation among males and females. A high genetic relatedness within both populations, indicated by mitochondrial data, is likely caused by a common historical origin or a combination of species-specific social organization and environmental dispersal constraints. We call for further research on the genetic divergence of bat-eared fox populations as well as on the genetic consequences of interactions between environmental characteristics and social organization in this species.

Patterns of rabies cases in South Africa between 1993 and 2019, including the role of wildlife.

Rabies is a global viral zoonosis endemic to South Africa, resulting in fatal encephalitis in warm-blooded animals, including humans. The loss of human lives and economic losses in rural areas through loss of livestock are substantial. A review was conducted of all confirmed animal rabies cases in South Africa from 1993 to 2019, with a total of 11701 cases identified to species level to assess the role that wildlife plays in the epidemiology of rabies. A spatio-temporal cluster analysis using a discrete Poisson space-time probability model, accounting for underlying estimated dog and livestock densities, identified 13 significant clusters (p<.05). These included four long-term clusters lasting more than 8years in duration and seven short-term clusters lasting less than 2years, with the remaining two clusters being of intermediate length. Outside of these endemic clusters, wildlife outbreaks in the remainder of South Africa were often less than one and a half years in duration most likely due to the rapid decline of wildlife vectors, especially jackals associated with rabies infection. Domestic dogs accounted for 59.8% of cases, with domestic cats (3.2%), livestock (21.1%) and wildlife (15.8%) making up the remainder of the cases. Yellow mongoose (Cynictis penicillata) was the most frequently affected wildlife species, followed by bat-eared fox (Otocyon megalotis), black-backed jackal (Canis mesomelas), meerkat (Suricata suricatta) and aardwolf (Proteles cristatus). Rabies in wildlife species followed different spatial distributions: black-backed jackal cases were more common in the north-western parts of South Africa, yellow mongoose cases more frequent in central South Africa, and bat-eared fox and aardwolf cases were more frequent in southern and western South Africa. Clusters often spanned several provinces, showing the importance of coordinated rabies control campaigns across administrative boundaries, and high-risk areas were highlighted for rabies in South Africa.

High-quality carnivoran genomes from roadkill samples enable comparative species delineation in aardwolf and bat-eared fox.

In a context of ongoing biodiversity erosion, obtaining genomic resources from wildlife is essential for conservation. The thousands of yearly mammalian roadkill provide a useful source material for genomic surveys. To illustrate the potential of this underexploited resource, we used roadkill samples to study the genomic diversity of the bat-eared fox (Otocyon megalotis) and the aardwolf (Proteles cristatus), both having subspecies with similar disjunct distributions in Eastern and Southern Africa. First, we obtained reference genomes with high contiguity and gene completeness by combining Nanopore long reads and Illumina short reads. Then, we showed that the two subspecies of aardwolf might warrant species status (P. cristatus and P. septentrionalis) by comparing their genome-wide genetic differentiation to pairs of well-defined species across Carnivora with a new Genetic Differentiation index (GDI) based on only a few resequenced individuals. Finally, we obtained a genome-scale Carnivora phylogeny including the new aardwolf species.

Seed dispersal potential of jackals and foxes in semi-arid habitats of South Africa

We determined the consumption of fruits and estimated potential seed dispersal of a canid community in semi-arid ecosystems of South Africa by comparing diets, defecation sites, densities and potential seed shadows of cape foxes (Vulpes chama), bat-eared foxes (Otocyon megalotis) and black-backed jackals (Canis mesomelas) on Benfontein and Rooipoort nature reserves. On Benfontein, all canid species consumed the fruit of Diospyros lycioides throughout the year. Jackals, but neither fox species, consumed relatively large amounts of Prosopis spp. (mesquite), an alien invasive. On Rooipoort, jackals had relatively high consumption of Ziziphus mucronata, followed by Grewia flava and D. lycioides. Bat-eared foxes had high consumption of fruit per area, although their seed dispersal potential was low due to their small potential seed shadow and poor germination sites. Cape foxes had the largest potential seed shadow, but their seed dispersal potential was low because of low fruit consumption, low density, and poor germination sites. Jackals had the highest seed dispersal potential because they consumed the most fruit species, had moderate densities, a relatively large potential seed shadow, and mostly good germination sites. We conclude that seed dispersal potential of South African canids, especially jackals, is more significant than previously known.

Rabies in the African Civet: An Incidental Host for Lyssaviruses?

In South Africa, canid rabies virus (RABV) infection is maintained in domestic and wildlife species. The identification of rabies in African civets raised the question of whether this wildlife carnivore is a potential reservoir host of RABVs of direct and ancestral dog origin (dog-maintained and dog-derived origins) with an independent cycle of transmission. Genetic analyses of African civet nucleoprotein sequences for 23 African civet RABVs and historically published sequences demonstrated that RABVs from African civets have two origins related to dog and mongoose rabies enzootics. The data support observations of the interaction of civets with domestic dogs and wildlife mongooses, mostly in Northern South Africa and North-East Zimbabwe. Within each host species clade, African civet RABVs group exclusively together, implying intra-species virus transfer occurs readily. The canid RABV clade appears to support virus transfer more readily between hosts than mongoose RABVs. Furthermore, these data probably indicate short transmission chains with conspecifics that may be related to transient rabies maintenance in African civets. Hence, it is important to continue monitoring the emergence of lyssaviruses in this host. Observations from this study are supported by ongoing and independent similar cases, in which bat-eared foxes and black-backed jackal species maintain independent rabies cycles of what were once dog-maintained RABVs.

Species-specific differences in Toxoplasma gondii, Neospora caninum and Besnoitia besnoiti seroprevalence in Namibian wildlife

BackgroundKnowledge about parasitic infections is crucial information for animal health, particularly of free-ranging species that might come into contact with livestock and humans.MethodsWe investigated the seroprevalence of three tissue-cyst-forming apicomplexan parasites (Toxoplasma gondii, Neospora caninum and Besnoitia besnoiti) in 506 individuals of 12 wildlife species in Namibia using in-house enzyme linked immunosorbent assays (indirect ELISAs applying purified antigens) for screening and immunoblots as confirmatory tests. We included six species of the suborder Feliformia, four species of the suborder Caniformia and two species of the suborder Ruminantia. For the two species for which we had most samples and life-history information, i.e. cheetahs (Acinonyx jubatus, n = 250) and leopards (Panthera pardus, n = 58), we investigated T. gondii seroprevalence in relation to age class, sex, sociality (solitary, mother-offspring group, independent sibling group, coalition group) and site (natural habitat vs farmland).ResultsAll but one carnivore species (bat-eared fox Otocyon megalotis, n = 4) were seropositive to T. gondii, with a seroprevalence ranging from 52.4% (131/250) in cheetahs to 93.2% (55/59) in African lions (Panthera leo). We also detected antibodies to T. gondii in 10.0% (2/20) of blue wildebeest (Connochaetes taurinus). Adult cheetahs and leopards were more likely to be seropositive to T. gondii than subadult conspecifics, whereas seroprevalence did not vary with sex, sociality and site. Furthermore, we measured antibodies to N. caninum in 15.4% (2/13) of brown hyenas (Hyaena brunnea) and 2.6% (1/39) of black-backed jackals (Canis mesomelas). Antibodies to B. besnoiti were detected in 3.4% (2/59) of African lions and 20.0% (4/20) of blue wildebeest.ConclusionsOur results demonstrate that Namibian wildlife species were exposed to apicomplexan parasites at different prevalences, depending on parasite and host species. In addition to serological work, molecular work is also needed to better understand the sylvatic cycle and the clear role of wildlife in the epidemiology of these parasites in southern Africa.

Spatial and temporal variation in the use of supplementary food in an obligate termite specialist, the bat-eared fox

The bat-eared fox (Otocyon megalotis) is considered a termite specialist. However, studies of its diet have been limited to indirect methods, such as scat and stomach content analyses, resulting in intraspecific dietary variations due in part to methodological differences. Because diet plays a central role in the social dynamics of these canids, we hereby contribute further to our knowledge about their dietary habits. We present 2-year data of direct observations of foraging bouts of 19 habituated bat-eared foxes in the kalahari desert of South Africa, as well as data on seasonal variation in invertebrate prey communities obtained through pitfall and sweep net trapping. Despite showing a diet breadth reflective of a specialised forager across all seasons, foxes exhibited substantial seasonal variation in diet breadth with a broader range of food categories utilised in summer compared to the other seasons. Supplementary food categories appear to not have been utilised opportunistically, but it is unclear what drove the preference for some food categories over others. A literature review indicated strong effects of local conditions on the utilisation of supplementary food across southern Africa. Our data support bat-eared foxes as obligate termite specialists but highlight that they appear to have the ability to show dietary flexibility based on both temporal and spatial variations in food abundance.

Ecology and epidemiology of rabies in humans, domestic animals and wildlife in Namibia, 2011-2017.

Rabies is a fatal zoonotic disease that causes a heavy burden on societies. Namibia, a country in southern Africa, is aiming at controlling the disease in its main reservoir, the domestic dog. To facilitate the implementation comprehensive information on the ecology and epidemiology of the disease and surveillance is of utmost importance. The study presented assesses the baseline data for both human and animal rabies surveillance in Namibia in recent times and establishes correlations with ecological and socio-economic data in order to provide an up-to-date picture on the epidemiology of rabies in Namibia. For instance, it was important to identify the main drivers in the epidemiology, and whether the control strategy by mass vaccination of dogs is undermined by cycles of rabies in wildlife. Rabies in humans was reported mainly from the Northern Communal Areas (NCAs), with a total of 113 cases from 2011 to 2017, representing an incidence of between 1.0 and 2.4 annual human rabies deaths per 100,000 inhabitants. Kavango, the region with the highest human rabies incidence was also the region with the lowest animal rabies surveillance intensity. Generally, the vast majority (77%) of dog samples originated from communal farm land, followed by urban areas (17%), while only a small fraction (3%) was submitted from freehold farm areas. In contrast, kudu and eland submissions were almost exclusively from freehold farmland (76%) and urban areas (19%), whereas the submission of cattle samples was evenly distributed among freehold farms (46%) and communal farm land (46%). The likelihood of sample submission decreased exponentially with distance to one of the two laboratories. Overall, 67% (N = 1,907) of all samples submitted tested rabies-positive, with the highest positivity rate observed in kudus (89%) and jackals (87%). The transmission cycle of rabies in dogs appears restricted to the northern communal areas of Namibia, whilst rabies in wildlife species is predominately reported from farmland in central Namibia, mostly affecting kudu (Tragelaphus strepsiceros) and livestock with a likely reservoir in wildlife canids such as jackals or bat-eared foxes. The analysis confirms the presence of two independent transmission cycles in Namibia with little geographic overlap, thus allowing for a sustainable control of rabies in dogs in the NCAs.

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, Kenya. Alternative management regimes have created a dichotomy in ecosystem conditions within the Reserve, where active enforcement of regulations maintains low levels of human disturbance in the Mara Triangle and passive enforcement of regulations in the Talek region permits multiple forms of human disturbance. Our results demonstrate that these alternative management regimes have variable effects on 11 observed carnivore species. As predicted, some species, such as African lions and bat-eared foxes, have higher population densities in the Mara Triangle, where regulations are actively enforced. Yet, other species, including black-backed jackals and spotted hyenas, have higher population densities in the Talek region where enforcement is passive. Multiple underlying mechanisms, including behavioral plasticity and competitive release, are likely causing higher black-backed jackals and spotted hyena densities in the disturbed Talek region. Our multispecies modeling framework reveals that carnivores do not react to management regimes uniformly, shaping carnivore communities by differentially producing winning and losing species. Some carnivore species require active enforcement of regulations for effective conservation, while others more readily adapt (and in some instances thrive in response) to lax management enforcement and resulting anthropogenic disturbance. Yet, high levels of human disturbance appear to be negatively affecting the majority of carnivores, with potential consequences that may permeate throughout the rest of the ecosystem. Community approaches to monitoring carnivores should be adopted as single species monitoring may overlook important intra-community variability.

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 infected animals and by incidental ingestion of oocysts from environmental contamination. Incidental ingestion should occur regardless of a species’ diet whereas the consumption of cysts should increase the chance of infection in carnivorous species. This predicts higher seropositivity in carnivorous than in insectivorous carnivores and lower seropositivity in juvenile carnivores with a long dependency on milk than in adults. We found high seropositivity in carnivorous species: 100% (15 of 15 samples) in adult African lions, 93% (38 of 41 samples) in adult spotted hyenas and one striped hyena sample was positive, whereas all four samples from the insectivorous bat-eared fox were negative. Juvenile hyenas (11 of 19 sera) had significantly lower seropositivity than adults (38 of 41 sera). Long-term monitoring of spotted hyenas revealed no significant difference in seropositivity between two periods (1988–1992 and 2000 to 2016). Identical results were produced in lion and hyena samples by a commercial multi-species ELISA (at serum dilution 1:10) and an in-house ELISA based on a recombinant T. gondii protein (at serum dilution 1:100), making the latter a useful alternative for small amounts of serum. We suggest that diet, age and lifetime range are factors determining seropositivity in carnivores in the Serengeti ecosystem and suggest that the role of small wild felids in the spread of T. gondii in the African ecosystem warrants investigation.

Friendly foxes: the relationship between steroid hormones and social behaviour in a monogamous African canid

AbstractAside from some studies on cooperatively breeding species, we know little about the underlying endocrine mechanisms of social behaviour in the order Carnivora. We investigated the correlations between steroid hormones and social behaviour in a socially monogamous canid, the bat‐eared fox (Otocyon megalotis). We collected faecal and observational data over 15 and 22 months, respectively, from 14 wild bat‐eared foxes in the Kalahari Desert, South Africa. These data were used to describe the relationship between faecal hormone metabolite concentrations and social behaviour. Faecal androgen metabolite (fAM) concentration differed by sex and mating season and was positively associated with faecal glucocorticoid metabolite (fGCM) levels. Male foxes had substantially higher fAM concentrations (median: 9.99 μg g−1 org. content, IQR = 7.39–11.62 μg g−1 org. content) than females (median: 1.93 μg g−1 org. content, IQR = 1.68–2.56 μg g−1 org. content). Higher fAM concentrations were associated with more social tolerance in female but not male foxes. Concentrations of fAM were positively associated with rate of inter‐group encounters in female foxes. Furthermore, fAM concentrations were also positively associated with the overall rate of negative social interactions for females. Finally, fAM concentrations were positively associated with scent‐marking behaviour in male, but not female foxes. There was no association between fGCM concentrations and any of the observed social behaviours in male foxes. Female foxes had a negative relationship between fGCM concentration and marking behaviour as well as social tolerance. There was no difference in fGCM concentration between female (median: 0.19 μg g−1 org. content, IQR = 0.16–0.23 μg g−1 org. content) and male (median: 0.22 μg g−1 org. content, IQR = 0.19–0.31 μg g−1 org. content) foxes. Our study is the first to describe the endocrine correlates of aggressive and affiliative behaviour in the monogamous bat‐eared fox. Androgens play an important role in mating behaviour in monomorphic, monogamous species where females might drive sexual selection.

Tameness does not correlate with the learning of an appetitive association in a wild canid.

Individual differences in cognition have been shown to be common in some animal taxa, and recent evidence suggests that an individual’s personality can be associated with an individual’s cognitive strategy. We tested whether wild bat-eared foxes Otocyon megalotis differ in a risk-taking behavior (tameness) and whether this trait correlated with appetitive association learning performance. While our result shows that individuals differed in their tameness, we found no association between this personality trait and learning the appetitive association. This result does not support the framework that differences in cognition are associated with differences in personality; however, our small sample size does not allow us to assert that personality cannot be associated with cognition in this system. This study highlights that measuring cognition and personality in wild systems presents added difficulty and that correlations found in captive animals may not be evident in their wild counterparts.

The influence of environmental and social factors on high- and low-cost vigilance in bat-eared foxes

Vigilance is commonly used to assess anti-predator behavior; however, the majority of studies assess only high-cost vigilance, which interrupts any other activities. Low-cost vigilance, by comparison, allows animals to be vigilant while engaged in other activities, thereby reducing the cost of vigilance. Here, we investigate the use of high- and low-cost vigilance in relation to environmental and temporal factors in a wild population of the bat-eared fox (Otocyon megalotis), a small mesopredator, using behavioral observations of eight habituated animals. We hypothesized that vigilance would increase with tall, dense vegetation, high wind speeds, and low ambient light, and that vigilance would decrease in the presence of conspecifics and over the period of a single observation session. Overall, bat-eared foxes spent significantly more time engaged in low-cost vigilance than in high-cost vigilance. High-cost vigilance increased with vegetation height, in the presence of adult conspecifics and in winter. We suggest these effects are due to impeded lines of sight with increases in vegetation height, increased competition in the presence of conspecifics, and increased social interactions in winter. Low-cost vigilance was highest at the start of observational sessions, and we suggest that this is due to observer effects, as foxes demonstrated increases in both high- and low-cost vigilance specifically towards observers during this time. This study demonstrates that foxes are highly dynamic in their vigilance behavior. Due to the low predation pressure in the study area, the use of mostly low-cost vigilance may be sufficient in this environment, and thus foxes can allocate more time to other activities. Our results indicate that, in this environment, vigilance is most likely driven by factors other than predation risk, but that foxes may still respond to certain cues of predation risk. Ultimately, in areas of low predation risk, species susceptible to predation may retain responses to cues of risk, but adapt behaviors to reduce the associated costs. While studies examining perceived risk in herbivores frequently assess vigilance, the examination of vigilance is largely under-investigated in mesopredators. Here, we present findings from one of the first studies to examine high- and low-cost vigilance in a small mesopredator. We demonstrate that in an area with minimal predation pressure low-cost vigilance is more intensively used and that despite the absence of predator sightings, ambush predators may still pose a perceived threat to foxes. Ultimately, when predation pressure is low, social interactions and competition may be some of the costliest activities. Results further indicate that while this small canid habituates quickly to observer presence, the initial presence of observers cannot be considered truly neutral.