Coexistence from a lion's perspective: Movements and habitat selection by African lions (Panthera leo) across a multi-use landscape.

Diminishing wild space and population fragmentation are key drivers of large carnivore declines worldwide. The persistence of large carnivores in fragmented landscapes often depends on the ability of individuals to move between separated subpopulations for genetic exchange and recovery from stochastic events. Where separated by anthropogenic landscapes, subpopulations' connectivity hinges on the area's socio-ecological conditions for coexistence and dispersing individuals' behavioral choices. Using GPS-collars and resource- and step-selection functions, we explored African lion (Panthera leo) habitat selection and movement patterns to better understand lions' behavioral adjustments in a landscape shared with pastoralists. We conducted our study in the Ngorongoro Conservation Area (NCA), Tanzania, a multiuse rangeland, that connects the small, high density lion subpopulation of the Ngorongoro Crater with the extensive Serengeti lion population. Landscape use by pastoralists and their livestock in the NCA varies seasonally, driven by the availability of pasture, water, and disease avoidance. The most important factor for lion habitat selection was the amount of vegetation cover, but its importance varied with the distance to human settlements, season and time of day. Although we noted high levels of individual variation in tolerance for humans, in general lions avoided humans on the landscape and used more cover when closer to humans. Females showed more consistent avoidance of humans and stronger use of cover when near humans than did males. Connectivity of lion subpopulations does not appear to be blocked by sparse pastoralist settlements, and nomadic males, key to subpopulation connectivity, significantly avoided humans during the day, suggesting a behavioral strategy for conflict mitigation. These results are consistent with lions balancing risk from humans with exploitation of livestock by altering their behaviors to reduce potential conflict. Our study lends some optimism for the adaptive capacity of lions to promote coexistence with humans in shared landscapes.

Social behavior: Male and female lions age differently.

Social aging - the change in social behavior across an individual's lifespan - has been found in many animals. A new study in African lions shows that female and male lions differ in their pattern of social aging.

Sex-specific social aging in wild African lions.

There is a growing interest in social behavior change with age,1,2,3,4,5 and the impacts of sociality on longevity,6,7,8 but current knowledge is broadly limited to primates, societies structured by dominance hierarchies, or single-sex studies. It is less clear how social aging patterns emerge in carnivores. The African lion (Panthera leo), a species that lives in egalitarian fission-fusion societies, presents an exceptional opportunity to examine social aging. Across felids, lions are unique in their dependence on conspecifics for many essential processes,9,10,11 and there is vast knowledge of lion behavioral ecology,10,11,12,13,14 including documented reproductive senescence in both sexes.14,15 Applying spatial-social network analyses across 30 years of data on the wild Serengeti lion population, we show that sex strongly modulates patterns of social aging and longevity. Group size increased with age for both sexes, but only males experienced significant changes in associate numbers (degree), specifically to females, which peaked in mid-life before declining. While aging females experienced declines in intra-sex connectivity (strength) and bond strength (mean strength), they peaked in both to males during mid-life. Male inter-sex strength also peaked in mid-life, while conversely their intra-sex strength and mean strength significantly dipped in mid-life. Although social associations were important for survival in both sexes, the investment diverged significantly: females' overall network connectivity was key for longevity, while the number of associates was important for males. These findings illustrate important potential effects of social aging in a wild carnivore and demonstrate how these diverge strongly between the sexes.

Multifaceted density dependence: Social structure and seasonality effects on Serengeti lion demography.

Interactions between density and environmental conditions have important effects on vital rates and consequently on population dynamics and can take complex pathways in species whose demography is strongly influenced by social context, such as the African lion, Panthera leo. In populations of such species, the response of vital rates to density can vary depending on the social structure (e.g. effects of group size or composition). However, studies assessing density dependence in populations of lions and other social species have seldom considered the effects of multiple socially explicit measures of density, and-more particularly for lions-of nomadic males. Additionally, vital-rate responses to interactions between the environment and various measures of density remain largely uninvestigated. To fill these knowledge gaps, we aimed to understand how a socially and spatially explicit consideration of density (i.e. at the local scale) and its interaction with environmental seasonality affect vital rates of lions in the Serengeti National Park, Tanzania. We used a Bayesian multistate capture-recapture model and Bayesian generalized linear mixed models to estimate lion stage-specific survival and between-stage transition rates, as well as reproduction probability and recruitment, while testing for season-specific effects of density measures at the group and home-range levels. We found evidence for several such effects. For example, resident-male survival increased more strongly with coalition size in the dry season compared with the wet season, and adult-female abundance affected subadult survival negatively in the wet season, but positively in the dry season. Additionally, while our models showed no effect of nomadic males on adult-female survival, they revealed strong effects of nomads on key processes such as reproduction and takeover dynamics. Therefore, our results highlight the importance of accounting for seasonality and social context when assessing the effects of density on vital rates of Serengeti lions and of social species more generally.

Factors influencing space-use and kill distribution of sympatric lion prides in a semi-arid savanna landscape.

Understanding lions' (Panthera leo) space-use is important for the management of multi-species wildlife systems because lions can have profound impacts on ecosystem-wide ecological processes. Semi-arid savanna landscapes are typically heterogeneous with species space-use driven by the availability and distribution of resources. Previous studies have demonstrated that lions select areas close to water as encounter rates with prey are higher and hunting success is greater in these regions. Where multiple lion prides exist, landscape partitioning is expected to follow a despotic distribution in which competitively superior prides occupy high-quality areas while subordinates select poorer habitats. In this study, Global Positioning System collar data and logistic regression were used to investigate space-use and hunting success among 50% of lion prides at Malilangwe Wildlife Reserve, Zimbabwe. Our findings show that lion space-use was driven by surface water availability and that home range selection was socially hierarchical with the dominant pride occupying habitat in which water was most abundant. In addition, we found that the effect of shrub cover, clay content and soil depth on kill probability was area specific and not influenced by hierarchical dominance. Where multiple lion prides are studied, we recommend treating prides as individual units because pooling data may obscure site and pride specific response patterns.

Counter-strategies to infanticide: The importance of cubs in determining lion habitat selection and social interactions.

Animal social and spatial behaviours are inextricably linked. Animal movements are driven by environmental factors and social interactions. Habitat structure and changing patterns of animal space use can also shape social interactions. Animals adjust their social and spatial behaviours to reduce the risk of offspring mortality. In territorial infanticidal species, two strategies are possible for males: they can stay close to offspring to protect them against rivals (infant-defence hypothesis) or patrol the territory more intensively to prevent rival intrusions (territorial-defence hypothesis). Here, we tested these hypotheses in African lions (Panthera leo) by investigating how males and females adjust their social and spatial behaviours in the presence of offspring. We combined datasets on the demography and movement of lions, collected between 2002 and 2016 in Hwange National Park (Zimbabwe), to document the presence of cubs (field observations) and the simultaneous movements of groupmates and competitors (GPS tracking). We showed a spatial response of lions to the presence of offspring, with females with cubs less likely to select areas close to waterholes or in the periphery of the territory than females without cubs. In contrast, these areas were more selected by males when there were cubs in the pride. We also found social responses. Males spent more time with females as habitat openness increased but the presence of cubs in the pride did not influence the average likelihood of observing males with females. Furthermore, rival males relocated further after an encounter with pride males when cubs were present in the prides, suggesting that the presence of cubs leads to a more vigorous repulsion of competitors. Males with cubs in their pride were more likely to interact with male competitors on the edge of the pride's home range and far from the waterholes, suggesting that they are particularly assiduous in detecting and repelling rival males during these periods. In general, the strategies to avoid infanticide exhibited by male lions supported the territorial-defence hypothesis. Our study contributes to answer the recent call for a behavioural ecology at the spatial-social interface.

Fear of the human "super predator" pervades the South African savanna.

Lions have long been perceived as Africa's, if not the world's, most fearsome terrestrial predator,1,2,3,4,5,6,7,8,9 the "king of beasts". Wildlife's fear of humans may, however, be far more powerful and all-prevailing1,10 as recent global surveys show that humans kill prey at much higher rates than other predators,10,11,12 due partly to technologies such as hunting with dogs or guns.11,13,14,15 We comprehensively experimentally tested whether wildlife's fear of humans exceeds even that of lions, by quantifying fear responses1 in the majority of carnivore and ungulate species (n = 19) inhabiting South Africa`s Greater Kruger National Park (GKNP),9,15,16,17 using automated camera-speaker systems9,18 at waterholes during the dry season that broadcast playbacks of humans, lions, hunting sounds (dogs, gunshots) or non-predator controls (birds).9,19,20,21,22 Fear of humans significantly exceeded that of lions throughout the savanna mammal community. As a whole (n = 4,238 independent trials), wildlife were twice as likely to run (p < 0.001) and abandoned waterholes in 40% faster time (p < 0.001) in response to humans than to lions (or hunting sounds). Fully 95% of species ran more from humans than lions (significantly in giraffes, leopards, hyenas, zebras, kudu, warthog, and impala) or abandoned waterholes faster (significantly in rhinoceroses and elephants). Our results greatly strengthen the growing experimental evidence that wildlife worldwide fear the human "super predator" far more than other predators,1,19,20,21,22,23,24,25,26,27,28 and the very substantial fear of humans demonstrated can be expected to cause considerable ecological impacts,1,6,22,23,24,29,30,31,32,33,34,35 presenting challenges for tourism-dependent conservation,1,36,37 particularly in Africa,38,39 while providing new opportunities to protect some species.1,22,40.

Tradeoffs between resources and risks shape the responses of a large carnivore to human disturbance.

Wide-ranging carnivores experience tradeoffs between dynamic resource availabilities and heterogeneous risks from humans, with consequences for their ecological function and conservation outcomes. Yet, research investigating these tradeoffs across large carnivore distributions is rare. We assessed how resource availability and anthropogenic risks influence the strength of lion (Panthera leo) responses to disturbance using data from 31 sites across lions' contemporary range. Lions avoided human disturbance at over two-thirds of sites, though their responses varied depending on site-level characteristics. Lions were more likely to exploit human-dominated landscapes where resources were limited, indicating that resource limitation can outweigh anthropogenic risks and might exacerbate human-carnivore conflict. Lions also avoided human impacts by increasing their nocturnal activity more often at sites with higher production of cattle. The combined effects of expanding human impacts and environmental change threaten to simultaneously downgrade the ecological function of carnivores and intensify human-carnivore conflicts, escalating extinction risks for many species.

Cloprostenol, a synthetic analog of prostaglandin F2α induces functional regression in cultured luteal cells of felids†.

In the present study, we investigated the effect of the synthetic analog of prostaglandin F2α (PGF2α)-cloprostenol-on cultured steroidogenic luteal cells of selected felid species over a 2-day culture period. The changes induced by cloprostenol were measured based on progesterone concentration and mRNA expression analysis of selected genes. Cloprostenol significantly reduced concentration of progesterone in cell culture medium of small luteal cells isolated from domestic cat corpora lutea (CL) at the development/maintenance stage (P < 0.05), but did not influence progesterone production in cultured cells from the regression stage. A decrease or complete silencing of progesterone production was also measured in cultured luteal cells of African lion (formation stage) and Javan leopard (development/maintenance stage). Gene-expression analysis by real-time PCR revealed that treatment with cloprostenol did not have an influence on expression of selected genes coding for enzymes of steroidogenesis (StAR, HSD3B, CYP11A1) or prostaglandin synthesis (PTGS2, PGES), nor did it effect hormone receptors (AR, ESR1, PGR, PTGER2), an anti-oxidative enzyme (SOD1) or factors of cell apoptosis (FAS, CASP3, TNFRSF1B, BCL2) over the studied period. Significant changes were measured only for expressions of luteinizing hormone (P < 0.05), prolactin (P < 0.05) and PGF2α receptors (P < 0.005) (LHCGR, PRLR, and PTGFR). The obtained results confirm that PGF2α/cloprostenol is a luteolytic agent in CL of felids and its impact on progesterone production depends on the developmental stage of the CL. Cloprostenol short-term treatment on luteal cells was associated only with functional but not structural changes related to luteal regression.

A 3D taphonomic model of long bone modification by lions in medium-sized ungulate carcasses.

Here, we present the first three-dimensional taphonomic analysis of a carnivore-modified assemblage at the anatomical scale of the appendicular skeleton. A sample of ten carcasses composed of two taxa (zebra and wildebeest) consumed by wild lions in the Tarangire National Park (Tanzania) has been used to determine element-specific lion damage patterns. This study presents a novel software for the 3D spatial documentation of bone surface modifications at the anatomical level. Combined with spatial statistics, the present analysis has been able to conclude that despite variable degrees of competition during carcass consumption, lions generate bilateral patterning consisting of substantial damage of proximal ends of stylopodials and zeugopodials, moderate damage of the distal ends of femora and marginal damage of distal ends of humeri and zeugopodials. Of special interest is, specifically, the patterning of tooth marks on shafts according to element, since these are crucial to determine not only the type of carnivore involved in any given bone assemblage, but also the interaction with other agents (namely, hominins, in the past). Lions leave few tooth marks on mid-shaft sections, mostly concentrated on certain sections and orientations of stylopodials and, to a lesser extent, of the proximal tibia. Redundant occurrence of tooth marks on certain bone sections renders them as crucial to attest lion agency in carcass initial consumption. Indirectly, this can also be used to determine whether hominins ever acquired carcasses at lion kills.

Humans disrupt access to prey for large African carnivores.

Wildlife respond to human presence by adjusting their temporal niche, possibly modifying encounter rates among species and trophic dynamics that structure communities. We assessed wildlife diel activity responses to human presence and consequential changes in predator-prey overlap using 11,111 detections of 3 large carnivores and 11 ungulates across 21,430 camera trap-nights in West Africa. Over two-thirds of species exhibited diel responses to mainly diurnal human presence, with ungulate nocturnal activity increasing by 7.1%. Rather than traditional pairwise predator-prey diel comparisons, we considered spatiotemporally explicit predator access to several prey resources to evaluate community-level trophic responses to human presence. Although leopard prey access was not affected by humans, lion and spotted hyena access to three prey species significantly increased when prey increased their nocturnal activity to avoid humans. Human presence considerably influenced the composition of available prey, with implications for prey selection, demonstrating how humans perturb ecological processes via behavioral modifications.

The role of kinship and demography in shaping cooperation amongst male lions.

The influence of kinship on animal cooperation is often unclear. Cooperating Asiatic lion coalitions are linearly hierarchical; male partners appropriate resources disproportionately. To investigate how kinship affect coalitionary dynamics, we combined microsatellite based genetic inferences with long-term genealogical records to measure relatedness between coalition partners of free-ranging lions in Gir, India. Large coalitions had higher likelihood of having sibling partners, while pairs were primarily unrelated. Fitness computations incorporating genetic relatedness revealed that low-ranking males in large coalitions were typically related to the dominant males and had fitness indices higher than single males, contrary to the previous understanding of this system based on indices derived from behavioural metrics alone. This demonstrates the indirect benefits to (related) males in large coalitions. Dominant males were found to 'lose less' if they lost mating opportunities to related partners versus unrelated males. From observations on territorial conflicts we show that while unrelated males cooperate, kin-selected benefits are ultimately essential for the maintenance of large coalitions. Although large coalitions maximised fitness as a group, demographic parameters limited their prevalence by restricting kin availability. Such demographic and behavioural constraints condition two-male coalitions to be the most attainable compromise for Gir lions.

Preference assessments as a tool to evaluate environmental enrichment.

Environmental enrichment is an important tool utilized to improve animal welfare in zoological institutions through opportunity for mental and physical stimulation. Many past studies have focused on the impact enrichment has on animal behavior; however, none have conducted preference assessments on enrichment items to examine the relationship between animals' preferences and interaction with enrichment over a 24-hr period. Ten-minute free operant, paired-choice preference assessments were implemented in Study 1 to determine the enrichment preferences of African lions (N = 3). Following Study 1, Study 2 was conducted, which examined the behavior of African lions with enrichment items over the course of 30, 24-hr trials to evaluate the relationship between preferences established in Study 1 and long-term interaction with the enrichment. Generalized estimating equations revealed a statistically significant relationship between the percentage of time the enrichment was approached first and the average duration of interaction in Study 1 to the total duration of interaction and the percent of hours interacted with the item in Study 2. Additionally, the first 2 min of the preference data resulted in comparable statistically significant findings, demonstrating shorter preference assessments can produce similar results. The results support our prediction that preference assessments can be used to estimate the amount of interaction with enrichment over the course of time, with preferred items being interacted with more frequently and in longer duration. Information gained from this study suggests preference assessments can be a time and cost-effective tool to evaluate enrichment preference and predicted efficacy.

Artificial eyespots on cattle reduce predation by large carnivores.

Eyespots evolved independently in many taxa as anti-predator signals. There remains debate regarding whether eyespots function as diversion targets, predator mimics, conspicuous startling signals, deceptive detection, or a combination. Although eye patterns and gaze modify human behaviour, anti-predator eyespots do not occur naturally in contemporary mammals. Here we show that eyespots painted on cattle rumps were associated with reduced attacks by ambush carnivores (lions and leopards). Cattle painted with eyespots were significantly more likely to survive than were cross-marked and unmarked cattle, despite all treatment groups being similarly exposed to predation risk. While higher survival of eyespot-painted cattle supports the detection hypothesis, increased survival of cross-marked cattle suggests an effect of novel and conspicuous marks more generally. To our knowledge, this is the first time eyespots have been shown to deter large mammalian predators. Applying artificial marks to high-value livestock may therefore represent a cost-effective tool to reduce livestock predation.

The evolutionary history of extinct and living lions.

Lions are one of the world's most iconic megafauna, yet little is known about their temporal and spatial demographic history and population differentiation. We analyzed a genomic dataset of 20 specimens: two ca. 30,000-y-old cave lions (Panthera leo spelaea), 12 historic lions (Panthera leo leo/Panthera leo melanochaita) that lived between the 15th and 20th centuries outside the current geographic distribution of lions, and 6 present-day lions from Africa and India. We found that cave and modern lions shared an ancestor ca. 500,000 y ago and that the 2 lineages likely did not hybridize following their divergence. Within modern lions, we found 2 main lineages that diverged ca. 70,000 y ago, with clear evidence of subsequent gene flow. Our data also reveal a nearly complete absence of genetic diversity within Indian lions, probably due to well-documented extremely low effective population sizes in the recent past. Our results contribute toward the understanding of the evolutionary history of lions and complement conservation efforts to protect the diversity of this vulnerable species.

Spatially explicit density and its determinants for Asiatic lions in the Gir forests.

Asiatic lions (Panthera leo persica) are an icon of conservation success, yet their status is inferred from total counts that cannot account for detection bias and double counts. With an effort of 4,797 km in 725 km2 of western Gir Protected Area, India, we used polygon search based spatially explicit capture recapture framework to estimate lion density. Using vibrissae patterns and permanent body marks we identified 67 lions from 368 lion sightings. We conducted distance sampling on 35 transects with an effort of 101.5 km to estimate spatial prey density using generalized additive modeling (GAM). Subsequently, we modeled lion spatial density with prey, habitat characteristics, anthropogenic factors and distance to baiting sites. Lion density (>1-year-old lions) was estimated at 8.53 (SE 1.05) /100 km2 with lionesses having smaller movement parameter (σ = 2.55 km; SE 0.12) compared to males (σ = 5.32 km; SE 0.33). Detection corrected sex ratio (female:male lions) was 1.14 (SE 0.02). Chital (Axis axis) was the most abundant ungulate with a density of 63.29 (SE 10.14) as determined by conventional distance sampling (CDS) and 58.17 (SE 22.17)/km2 with density surface modeling (DSM), followed by sambar (Rusa unicolor) at 3.84 (SE 1.07) and 4.73 (SE 1.48)/km2 estimated by CDS and DSM respectively. Spatial lion density was best explained by proximity to baiting sites and flat valley habitat but not as much by prey density. We demonstrate a scientifically robust approach to estimate lion abundance, that due to its spatial context, can be useful for management of habitat and human-lion interface. We recommend this method for lion population assessment across their range. High lion densities in western Gir were correlated with baiting. The management practice of attracting lions for tourism can perturb natural lion densities, disrupt behavior, lion social dynamics and have detrimental effects on local prey densities.

Reproductive cycle stage assessment using vaginal cytology evaluation in African lions (Panthera leo).

Vaginal cytology evaluation is an economic, non-invasive technique for indirect monitoring of fluctuations in estrogen concentrations, and thus progression of the estrous cycle. This technique is widely used in domestic dogs for determining timing of artificial insemination. There, however, are only a few reports on the vaginal cytology of non-domestic felids, including lions. This study was conducted, therefore, to describe the vaginal epithelial changes throughout the reproductive cycle of African lions, and to investigate the efficacy of vaginal cytology assessments for predicting reproductive stages. During a 12-month period, reproductive behavioral data and vaginal swabs were collected daily from five lionesses. In total, 541 vaginal smears were evaluated for the proportion of mucosal epithelial cells, neutrophils, bacterial cells, and amount of mucous, cellular debris. One single swab with a large proportion of superficial cells, absence of neutrophils, large number of bacteria, without cellular debris was sufficient for detecting lionesses in estrus. Likewise, one cytology sample with a large proportion of parabasal and intermediate cells, few neutrophils, few bacteria, and large amount of mucous, cellular debris enabled detection of females in advanced diestrus or gestation. To distinguish lionesses in early diestrus from those in an inter-estrous period, at least two consecutive swabs were necessary for satisfactory classification. Overall, evaluation of vaginal cytology samples was an effective technique for differentiation among different stages of the reproductive cycle, confirmation of estrus, and pregnancy diagnosis in lionesses. This technique, therefore, has the potential for application in classifying different stages of the reproductive cycle in other feline species.

Positive Reinforcement Conditioning as a Tool for Frequent Minimally Invasive Blood and Vaginal Swab Sampling in African Lions (Panthera Leo).

Information regarding the physiology of African lions is scarce, mainly due to challenges associated with essential routine research procedures. The aim of this experiment was to test the possibility of training six captive lionesses by positive reinforcement conditioning (PRC) to voluntarily allow the collection of vaginal swabs and blood samples. This was done with the final goal of avoiding frequent anesthesia, and potentially stressful management during reproduction research. All lionesses mastered basic clicker and targeting principles within 2 weeks. Routine sampling was possible after 20 weeks of training, enabling the collection of about 750 vaginal swabs and 650 blood samples over 18 months. The animals remained calm and cooperative during all sessions, and demonstrated curiosity in the training. PRC training of captive lionesses proved to be a suitable, minimally invasive method for repeated collection of vaginal swabs and blood. Additionally, PRC may serve as behavioral enrichment for African lions in captive settings. Compared to chemical or physical restraining methods, this noninvasive management approach may reduce distress and physiological negative side effects, thus opening up new avenues for feline research.

A Pilot Study for Estimating the Cardiopulmonary Signals of Diverse Exotic Animals Using a Digital Camera.

Monitoring the cardiopulmonary signal of animals is a challenge for veterinarians in conditions when contact with a conscious animal is inconvenient, difficult, damaging, distressing or dangerous to personnel or the animal subject. In this pilot study, we demonstrate a computer vision-based system and use examples of exotic, untamed species to demonstrate this means to extract the cardiopulmonary signal. Subject animals included the following species: Giant panda (Ailuropoda melanoleuca), African lions (Panthera leo), Sumatran tiger (Panthera tigris sumatrae), koala (Phascolarctos cinereus), red kangaroo (Macropus rufus), alpaca (Vicugna pacos), little blue penguin (Eudyptula minor), Sumatran orangutan (Pongo abelii) and Hamadryas baboon (Papio hamadryas). The study was done without need for restriction, fixation, contact or disruption of the daily routine of the subjects. The pilot system extracts the signal from the abdominal-thoracic region, where cardiopulmonary activity is most likely to be visible using image sequences captured by a digital camera. The results show motion on the body surface of the subjects that is characteristic of cardiopulmonary activity and is likely to be useful to estimate physiological parameters (pulse rate and breathing rate) of animals without any physical contact. The results of the study suggest that a fully controlled study against conventional physiological monitoring equipment is ethically warranted, which may lead to a novel approach to non-contact physiological monitoring and remotely sensed health assessment of animals. The method shows promise for applications in veterinary practice, conservation and game management, animal welfare and zoological and behavioral studies.

Carnivores, competition and genetic connectivity in the Anthropocene.

Current extinction rates are comparable to five prior mass extinctions in the earth's history, and are strongly affected by human activities that have modified more than half of the earth's terrestrial surface. Increasing human activity restricts animal movements and isolates formerly connected populations, a particular concern for the conservation of large carnivores, but no prior research has used high throughput sequencing in a standardized manner to examine genetic connectivity for multiple species of large carnivores and multiple ecosystems. Here, we used RAD SNP genotypes to test for differences in connectivity between multiple ecosystems for African wild dogs (Lycaon pictus) and lions (Panthera leo), and to test correlations between genetic distance, geographic distance and landscape resistance due to human activity. We found weaker connectivity, a stronger correlation between genetic distance and geographic distance, and a stronger correlation between genetic distance and landscape resistance for lions than for wild dogs, and propose a new hypothesis that adaptations to interspecific competition may help to explain differences in vulnerability to isolation by humans.