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The interspecific interactions of apex predators are integral to the function of ecological communities, but most studies have focused on understanding their top down effects. Kleptoparasitism (the stealing of procured food) by dominant scavengers can have negative effects on populations and behaviors of apex predators. We captured 7 pumas (Puma concolor) and fitted them with GPS collars to investigate potential kill sites (n = 352), some of which we monitored with camera traps (n = 58). We analyzed whether observed kleptoparasitism by American black bears (Ursus americanus) affected puma energetics and foraging behavior. We found that black bears were the most frequent scavenger of puma kills (72.4%), and we documented bears scavenging puma kills during every month. The top model for bear detection of puma kills included prey size, temperature, and canopy cover, with bears more likely to scavenge from adult black-tailed deer (Odocoileus hemionus columbianus) carcasses in warmer temperatures and under dense canopy cover. When black bear scavenging occurred, pumas spent 22% less time at their kill and incurred energetic losses. In response, pumas shortened their inter-kill intervals by 1.3 days thus increasing their kill rates. Our results demonstrate how a dominant scavenger directly mediates the foraging behavior of an apex predator. These results suggest that community interactions do not necessarily start at the top in top-down systems, and the effects of predators on prey populations can only be understood within their respective ecological communities.

Female–female sexual behaviors have been recorded in many species across several taxa, but their infrequency except in a few species has resulted in continued speculation about their function and potential evolutionary consequences. Here, we report two observations of female–female mounting in wild puma populations representing two sub-species from opposite ends of puma range. We believe our observations provided support for the social glue hypothesis and dominance in same-sex hierarchies, but not for surrogacy in the absence of a male or as a means to stimulate and encourage male partners to copulate.

SummaryWe tested for plague (Yersinia pestis) in a puma population in the Greater Yellowstone Ecosystem (GYE) over 9 years, overlapping a case when a boy in the area became infected with plague. Antibodies to Y. pestis were detected in 8 of 17 (47%) pumas tested by complement-enzyme-linked immunosorbent assay, and the organism itself was detected in 4 of 11 (36%) pumas tested after necropsy. Neither puma sex nor age was significantly associated with Y. pestis exposure or mortality, although our sample size was small. The overall prevalence of exposure we recorded was similar to that found along the western slope of Colorado, which is adjacent to the Four Corners region, a known plague hotspot in the USA. This suggests that: (1) Y. pestis may be present at higher levels in the GYE than previously assumed; (2) plague is a significant source of mortality for local pumas (6.6% of sub-adult and adult mortality); and (3) pumas may be a useful sentinel for potential risk of plague exposure to humans throughout the West. We would also emphasize that hunters and others handling pumas in this region should be made aware of the possibility of exposure.

Noise is the non-target search results that people encounter when searching for a particular topic of interest; it is also the cloud of distracting data that can obscure or deflect conservation communication. Online noise associated with large carnivores is particularly dense because their defining characteristics make them salient. Mountain lions (Puma concolor) exemplify noise associated with multiple vernaculars for a species in the crosshairs of conservation conundrums. We compared internet search results, Google Trends reflecting topic interest, use in science publications and sentiment in print and online media for P. concolor's most frequent vernacular names, “mountain lion,” “cougar,” “puma” and “Florida panther.” Puma and panther exhibited greater noise and salience than cougar or mountain lion, but, results for mountain lion, followed by cougar, yielded the highest biological relevance. Online sentiment negatively correlated with biological relevance, with positive sentiment highest for the noisiest vernaculars, puma and panther. As conservation practitioners, we must recognize that public outreach is part of our scientific agenda and be conscious of crafting communication that reaches and resonates with our intended audiences.

Human activity and land use change impact every landscape on Earth, driving declines in many animal species while benefiting others. Species ecological and life history traits may predict success in human-dominated landscapes such that only species with "winning" combinations of traits will persist in disturbed environments. However, this link between species traits and successful coexistence with humans remains obscured by the complexity of anthropogenic disturbances and variability among study systems. We compiled detection data for 24 mammal species from 61 populations across North America to quantify the effects of (1) the direct presence of people and (2) the human footprint (landscape modification) on mammal occurrence and activity levels. Thirty-three percent of mammal species exhibited a net negative response (i.e., reduced occurrence or activity) to increasing human presence and/or footprint across populations, whereas 58% of species were positively associated with increasing disturbance. However, apparent benefits of human presence and footprint tended to decrease or disappear at higher disturbance levels, indicative of thresholds in mammal species' capacity to tolerate disturbance or exploit human-dominated landscapes. Species ecological and life history traits were strong predictors of their responses to human footprint, with increasing footprint favoring smaller, less carnivorous, faster-reproducing species. The positive and negative effects of human presence were distributed more randomly with respect to species trait values, with apparent winners and losers across a range of body sizes and dietary guilds. Differential responses by some species to human presence and human footprint highlight the importance of considering these two forms of human disturbance separately when estimating anthropogenic impacts on wildlife. Our approach provides insights into the complex mechanisms through which human activities shape mammal communities globally, revealing the drivers of the loss of larger predators in human-modified landscapes.

© 2017 American Society of Mammalogists. Global positioning system (GPS) technology has revolutionized the study of carnivores. Researchers commonly estimate kill rates with GPS data using the following steps. Firstly, researchers mark individual animals and fit them with GPS collars. Next, they visit a subset of "GPS clusters" (aggregated location data) during field surveys and assign spatiotemporal covariates associated with predation and non-predation events. Lastly, they develop predictive models with data collected in the field to estimate the probability that each cluster they did not visit in the field was a predation event. Such predation models help reduce field efforts and save money; however, these models are prone to error when carnivores eat prey of different sizes or exhibit shorter-than-expected handling times. We simulated reduced field efforts to investigate the reliability of predictive modeling in determining diet composition and detecting predation events for 3 puma (Puma concolor) populations with different prey assemblages and potential effects on handling time of carcasses. We visited a total 1,896 clusters in Chilean Patagonia, Colorado, and California, of which 1,752 clusters (∼92%) were included to build and test predation models. Across all study areas, the total time a puma spent at a cluster was the only reliable predictor of a cluster being a predation event. When we reduced field efforts by selectively removing GPS clusters < 12 and < 24 h in length, model performance improved but produced inaccurate results. Predation models underestimated the number of predation events in California and Colorado and significantly over-or underestimated the number of predation events in Patagonia. Selectively reducing field efforts also reduced the diversity and evenness of prey we recorded in puma diets. Randomly reducing field efforts, in contrast, reduced the precision of model estimates. Our results highlight the importance of conducting intensive fieldwork over predation modeling to measure prey selection and kill rates of carnivores.

© 2018 The Authors. Ecology and Evolution published by John Wiley & Sons Ltd. Humans are primary drivers of declining abundances and extirpation of large carnivores worldwide. Management interventions to restore biodiversity patterns, however, include carnivore reintroductions, despite the many unresolved ecological consequences associated with such efforts. Using multistate capture–mark–recapture models, we explored age-specific survival and cause-specific mortality rates for 134 pumas (Puma concolor) monitored in the Greater Yellowstone Ecosystem during gray wolf (Canis lupus) recovery. We identified two top models explaining differences in puma survivorship, and our results suggested three management interventions (unsustainable puma hunting, reduction in a primary prey, and reintroduction of a dominant competitor) have unintentionally impacted puma survival. Specifically, puma survival across age classes was lower in the 6-month hunting season than the 6-month nonhunting season; human-caused mortality rates for juveniles and adults, and predation rates on puma kittens, were higher in the hunting season. Predation on puma kittens, and starvation rates for all pumas, also increased as managers reduced elk (Cervus elaphus) abundance in the system, highlighting direct and indirect effects of competition between recovering wolves and pumas over prey. Our results emphasize the importance of understanding the synergistic effects of existing management strategies and the recovery of large, dominant carnivores to effectively conserve subordinate, hunted carnivores in human-dominated landscapes.

Ecosystem engineers create physical changes in abiotic and biotic material, and through this process control the availability of resources for other species. Predators that abandon large portions of their prey may be ecosystem engineers that create habitat for carrion-dependent invertebrates that utilize carcasses during critical life-history periods. Between 04-May-2016 and 04-Oct-2016, we sampled beetle assemblages at 18 carcasses of prey killed by pumas and matching control sites in the southern Greater Yellowstone Ecosystem, USA, to measure the extent to which beetle families utilized these carcass "habitats". We used generalized linear-mixed models and linear-mixed effect models to examine changes in beetle abundance, species richness, and Simpson's Index of Diversity. We estimated kill rates and carrion production rates for individual pumas to better assess the impact of pumas on invertebrate communities. We collected 24,209 beetles representing 215 species. We identified eight beetle families that had significantly higher abundance at carcasses than control sites. Carcasses had a statistically large to very large effect (determined using Cohen's d) on beetle abundance, richness, and diversity for the initial 8 weeks of sampling. Our research revealed strong effects of an ecosystem engineer on beetle assemblages while highlighting the potential role of apex predators in creating and modifying physical habitats for carrion-dependent species. This suggests that there may be consequences for invertebrate communities where apex predators exist at reduced numbers or have been eradicated. The ecological role of invertebrates is often overlooked, yet they are essential taxa that provide critical ecological services upon which we depend.

Carrion promotes biodiversity and ecosystem stability, and large carnivores provide this resource throughout the year. In particular, apex felids subordinate to other carnivores contribute more carrion to ecological communities than other predators. We measured vertebrate scavenger diversity at puma (Puma concolor) kills in the Greater Yellowstone Ecosystem, and utilized a model-comparison approach to determine what variables influenced scavenger diversity (Shannon's H) at carcasses. We documented the highest vertebrate scavenger diversity of any study to date (39 birds and mammals). Scavengers represented 10.9% of local birds and 28.3% of local mammals, emphasizing the diversity of food-web vectors supported by pumas, and the positive contributions of pumas and potentially other subordinate, apex felids to ecological stability. Scavenger diversity at carcasses was most influenced by the length of time the carcass was sampled, and the biological variables, temperature and prey weight. Nevertheless, diversity was relatively consistent across carcasses. We also identified six additional stalk-and-ambush carnivores weighing > 20 kg, that feed on prey larger than themselves, and are subordinate to other predators. Together with pumas, these seven felids may provide distinctive ecological functions through their disproportionate production of carrion and subsequent contributions to biodiversity. We urge conservation managers to increase support for these species, as a means of prioritizing resources to best ensure the persistence of carrion in natural systems.

Ecotourism enhances conservation management, promotes non-consumptive use of wildlife, and increases local community resources over that of select individuals when compared with consumptive uses such as hunting or trapping. The bobcat is a cryptic mesocarnivore widely exploited for pelts across North America, and a species increasingly contributing to ecotourism. Here, we report a conservative, non-consumptive economic value of US$308,105 for a single bobcat in Yellowstone National Park in northwest Wyoming for the 2015–2016 winter season, a figure nearly 1000 times greater than exploitive values of US$315.17 per bobcat trapped or hunted in Wyoming in the same season (US$130.53 per bobcat harvested in revenue earned by the state of Wyoming in trapping license sales + US$184.64 per pelt sold by successful trappers and hunters). In 2016, tourism was the second largest industry in Wyoming and generated US$3.2 billion. Our case study emphasizes that current bobcat regulatory policies across North America do not reflect current cultural values, inclusive of both consumptive and non-consumptive use of wildlife. Therefore, we recommend range-wide regulatory changes to ensure bobcat management is not just sustainable in terms of harvest, but that all people have access to shared resources held in trust.

A Brownian motion whose infinitesimal variance alternates according to a telegraph process is considered. This stochastic process can be employed to model a variety of real-word situations, such as animal movement in ecology and stochastic volatility in mathematical finance. The main goal is to develop an estimation procedure for the underlying model parameters when the process is observed at discrete, possibly irregularly spaced time points. The sequence of observations is not Markov, but the sequence of the state of the telegraph process, if observed, is Markov. The observed sequence is therefore from a hidden Markov model. Likelihood inference is developed via dynamic programming, and is demonstrated to have much higher efficiency than the composite likelihood approach that was applied in an earlier work. The model is applied to model the movement of a mountain lion.

Predator tourism is one strategy to improve tolerance for predators, and support biodiversity and ecosystem health. Torres del Paine National Park (TdP) – a UNESCO Biosphere Reserve in southern Chile - supports productive livestock industries and nascent puma tourism. We compared interviews conducted in the region prior to puma tourism, with results from interviews collected across 45 ranches post-puma tourism. We assessed rancher attitudes regarding pumas, puma-livestock conflict, puma tourism, and linked them with socio-ecological factors. Respondents who viewed pumas as a threat experienced higher livestock losses. Respondents who reported higher sheep losses were inclined to support the lethal removal of livestock-killing pumas, and to initiate a puma hunt, whereas respondents who supported puma tourism disagreed with hunting pumas. Using the Potential for Conflict Index, we found that participants exhibited the highest consensus on the benefit of puma tourism and the lowest consensus over lethal removal of pumas. Our results suggest predator tourism has increased tolerance for pumas but is creating new potential for conflict. Previous to puma tourism, ranchers were almost entirely negative about pumas and unanimously supported illegal puma hunting. Now, most believe that pumas are part of Patagonia's heritage. This divide was best explained by distance to TdP: ranches closer to TdP experienced greater losses to pumas but had neighbours that benefitted most from puma tourism. Therefore, we suggest that tourism revenues supplement community compensation insurance programs that reimburse rancher losses to pumas to mitigate the growing divide between those benefiting from pumas and those experiencing economic hardship.

Many species have been increasingly recognized as an aggregate of individual dietary specialists. Previous work has emphasized the importance of individual dietary specialization in driving many ecological processes, but less is known about the relationship between individual diet and habitat use. We used data from 7 cougars and 331 predation events collected in western Colorado from 2010 to 2013 to test whether intraspecific variation in cougar (Puma concolor) diet resulted from chance encounters or from targeting particular prey species. One cougar within our study population (P06) selected for American beaver (Castor canadensis) more than expected based on availability, spent a disproportionate amount of time within beaver habitat, and exhibited reduced travel speeds when near waterways. Our results present evidence that specialist diets in predators are likely reflective of additional differences in foraging behaviors rather than random encounters with prey species (e.g., prey availability).

Prey selection is exhibited by predator populations that kill a prey species disproportionate to its availability, or alternatively, individual predators that select prey disproportionate to the mean selection exhibited by their populations. Prey selection is a simple calculation when one can determine prey availability; however, measuring prey availability is challenging. We compared population- and individual-level prey selection as determined with two measures of prey availability for five ungulate species killed by pumas (Puma concolor (L., 1771)) in the Southern Yellowstone Ecosystem, USA: (1) annual prey counts and (2) total prey killed by marked pumas. We also tested whether individual pumas in the population exhibited a narrower dietary niche breadth compared with their population as a whole. The two methods yielded different estimates of prey availability and highlighted the need to consciously match prey availability estimates with appropriate ecological questions. Prey counts may have overestimated elk (Cervus canadensis (Erxleben, 1777)) abundance and underestimated deer abundance, whereas predation data may have better captured the influence of prey size on puma-specific prey vulnerability and availability. Prey counts were the more appropriate metric for analyzing population-level prey selection or differences in interspecific foraging, whereas total prey killed was the more appropriate metric for intraspecific comparisons.

Carrion is a rich, ephemeral resource vital to biodiversity and ecosystem health. In temperate ecosystems in which cold temperatures and snowfall influence the accessibility and availability of small prey and seasonal mast crops, carrion may also be a limiting resource for mesocarnivores like red foxes (Vulpes vulpes), which are too small to predate ungulates. Using motion-triggered video cameras and generalized linear mixed models, we studied the spatial and temporal patterns of red fox scavenging at 232 mountain lion kills in the southern Greater Yellowstone Ecosystem (GYE) from 2012–2015. We found that red foxes scavenged mountain lion kills across all habitats throughout the year, however, red fox behaviors varied with season. In winter, we documented red foxes at a greater proportion of mountain lion kills (70.3% in winter vs. 48.9% in summer), and in greater numbers (1.83 foxes per kill in winter vs. 1.16 in summer). In winter, red foxes fed longer (= 102.7 ± 138.3 minutes feeding in winter vs. = 39.7 ± 74.0 in summer), and they more often scavenged while the mountain lion was nearby. We speculated that red foxes may have increased risk taking in winter due to hunger driven by resource scarcity. Our research highlighted an important ecological relationship between red foxes and mountain lions in the GYE. Mountain lions tolerate high levels of scavenging, so the frequency and intensity of red fox scavenging at their kills may not impact mountain lions, but instead facilitate the dispersion and benefits of resources created by this apex predator. Large carnivores, and mid-trophic felids like mountain lions in particular, are essential producers of carrion vital to biodiversity and ecosystem health. In turn, scavengers play critical roles in distributing these resources and increasing the heterogeneity of resources that support biodiversity and ecosystem structure, as well as ecological resilience.

BackgroundInterspecific competition affects species fitness, community assemblages and structure, and the geographic distributions of species. Established dominance hierarchies among species mitigate the need for fighting and contribute to the realized niche for subordinate species. This is especially important for apex predators, many of which simultaneous contend with the costs of competition with more dominant species and the costs associated with human hunting and lethal management.MethodsPumas are a widespread solitary felid heavily regulated through hunting to reduce conflicts with livestock and people. Across their range, pumas overlap with six apex predators (gray wolf, grizzly bear, American black bear, jaguar, coyote, maned wolf), two of which (gray wolf, grizzly bear) are currently expanding in North America following recovery efforts. We conducted a literature search to assess whether pumas were subordinate or dominant with sympatric apex predators, as well as with three felid mesocarnivores with similar ecology (ocelot, bobcat, Canada lynx). We also conducted an analysis of the spatial distributions of pumas and their dominant sympatric competitors to estimate in what part of their range, pumas are dominant versus subordinate.ResultsWe used 64 sources to assess dominance among pumas and other apex predators, and 13 sources to assess their relationships with felid mesocarnivores. Evidence suggested that wolves, grizzly bears, black bears, and jaguars are dominant over pumas, but that pumas are dominant over coyotes and maned wolves. Evidence suggested that pumas are also dominant over all three felid mesocarnivores with which they share range. More broadly, pumas are subordinate to at least one other apex carnivore in 10,799,252 (47.5%) of their 22,735,268 km2range across North and South America.DiscussionSubordinate pumas change their habitat use, suffer displacement at food sources, likely experience increased energetic demands from harassment, exhibit increased starvation, and are sometimes directly killed in competitive interactions with dominant competitors. Nevertheless, we lack research clearly linking the costs of competition to puma fitness. Further, we lack research that assesses the influence of human effects simultaneous with the negative effects of competition with other sympatric carnivores. Until the time that we understand whether competitive effects are additive with human management, or even potentially synergistic, we encourage caution among managers responsible for determining harvest limits for pumas and other subordinate, apex carnivores in areas where they are sympatric with dominant species. This may be especially important information for managers working in regions where wolves and brown bears are recolonizing and recovering, and historic competition scenarios among multiple apex predators are being realized.

As technology has improved, our ability to study cryptic animal behavior has increased. Bed site selection is one such example. Among prey species, bed site selection provides thermoregulatory benefits and mitigates predation risk, and may directly influence survival. We conducted research to test whether a subordinate carnivore also selected beds with similar characteristics in an ecosystem supporting a multi-species guild of competing predators. We employed a model comparison approach in which we tested whether cougar (Puma concolor) bed site attributes supported the thermoregulatory versus the predator avoidance hypotheses, or exhibited characteristics supporting both hypotheses. Between 2012–2016, we investigated 599 cougar bed sites in the Greater Yellowstone Ecosystem and examined attributes at two scales: the landscape (second-order,n = 599) and the microsite (fourth order,n = 140). At the landscape scale, cougars selected bed sites in winter that supported both the thermoregulatory and predator avoidance hypotheses: bed sites were on steeper slopes but at lower elevations, closer to the forest edge, away from sagebrush and meadow habitat types, and on southern, eastern, and western-facing slopes. In the summer, bed attributes supported the predator avoidance hypothesis over the thermoregulation hypothesis: beds were closer to forest edges, away from sagebrush and meadow habitat classes, and on steeper slopes. At the microsite scale, cougar bed attributes in both the winter and summer supported both the predator avoidance and thermoregulatory hypotheses: they selected bed sites with high canopy cover, high vegetative concealment, and in a rugged habitat class characterized by cliff bands and talus fields. We found that just like prey species, a subordinate predator selected bed sites that facilitated both thermoregulatory and anti-predator functions. In conclusion, we believe that measuring bed site attributes may provide a novel means of measuring the use of refugia by subordinate predators, and ultimately provide new insights into the habitat requirements and energetics of subordinate carnivores.

© 2016 by the Ecological Society of America. Encounter competition is interference competition in which animals directly contend for resources. Ecological theory predicts the trait that determines the resource holding potential (RHP), and hence the winner of encounter competition, is most often body size or mass. The difficulties of observing encounter competition in complex organisms in natural environments, however, has limited opportunities to test this theory across diverse species. We studied the outcome of encounter competition contests among mesocarnivores at deer carcasses in California to determine the most important variables for winning these contests. We found some support for current theory in that body mass is important in determining the winner of encounter competition, but we found that other factors including hunger and species-specific traits were also important. In particular, our top models were "strength and hunger" and "size and hunger," with models emphasizing the complexity of variables influencing outcomes of encounter competition. In addition, our wins above predicted (WAP) statistic suggests that an important aspect that determines the winner of encounter competition is species-specific advantages that increase their RHP, as bobcats (Lynx rufus) and spotted skunks (Spilogale gracilis) won more often than predicted based on mass. In complex organisms, such as mesocarnivores, species-specific adaptations, including strategic behaviors, aggressiveness, and weapons, contribute to competitive advantages and may allow certain species to take control or defend resources better than others. Our results help explain how interspecific competition shapes the occurrence patterns of species in ecological communities.

Mate selection influences individual fitness, is often based on complex cues and behaviours, and can be difficult to study in solitary species including carnivores. We used motion-triggered cameras at 29 community scrapes (i.e. scent marking locations used by multiple individuals) and home range data from 39 GPS-collared pumas (Puma concolor) to assess the relevance of communication behaviours for mate selection by female pumas in California. Female pumas visited community scrapes irregularly and visitation bouts appeared to be correlated with oestrus. Female pumas on average selected from 1.7 collared males, and selection was based on multiple cues that varied among the different time periods measured (i.e. the female’s visitation bout and in 90 days previous to the consorting event). Female mate selection over the course of a visitation bout was based on frequency of the male visitation, mass, and age. In the 90 days previous to consorting, the number of scrapes a male created was the most important contributor to selection, which was likely related to his residency status. We also found that at least 14% of females mated with multiple males, thus possibly confusing paternity. Our findings provide a mechanistic understanding of how female pumas use scent and auditory communication at community scrapes to select dominant resident males to mate with.

Context Many institutions of wildlife management and their hunting constituents tend to value ungulates over large carnivores, in part due to financial incentives associated with ungulate hunting over carnivore hunting. This system benefits from mythology that presents large carnivores as competitors for antlered male ungulates most prized by the hunting community. Aims We explored puma (Puma concolor) foraging and prey selection in two study areas in the Rocky Mountains, USA, to test whether pumas were competing with human hunters for antlered elk (Cervus elaphus) and mule deer (Odocoileus hemionus). Methods We employed GPS technology to track pumas and document their prey. We measured population- and individual-level selection by comparing prey killed by pumas to two estimates of prey availability: (1) landscape-level as determined by annual agency game counts; and (2) total prey killed by marked pumas. Key results Pumas in both study systems killed small numbers of antlered elk and mule deer. Pumas exhibited avoidance of mature elk, instead strongly selecting for elk calves over any other age or sex class. Pumas in both systems also selected for mule deer fawns; however, they also exhibited small positive selection (Jacob’s index of 0.08 in CO and 0.11 in WY on a scale of 0.0–1.0) for antlered mule deer. Conclusions In terms of numbers killed, pumas were not a competitor with human hunters for either antlered species. In terms of prey selection, pumas showed that they may be greater competition for rare antlered mule deer but not for antlered elk. In both study sites, antlered elk and deer remained at levels at which they could perform their ecological functions. Implications Our results highlight the fact that the overhunting of large carnivores over competition for antlered ungulates is mostly unfounded; we should instead focus management, media attention and conservation science on disentangling the complex ecology driving localised declines of mule deer, elk and other important ungulate resources, many of which are anthropogenic in nature and can be addressed.

There are several alternative hypotheses about the effects of territoriality, kinship and prey availability on individual carnivore distributions within populations. The first is the land-tenure hypothesis, which predicts that carnivores regulate their density through territoriality and temporal avoidance. The second is the kinship hypothesis, which predicts related individuals will be clumped within populations, and the third is the resource dispersion hypothesis, which suggests that resource richness may explain variable sociality, spatial overlap or temporary aggregations of conspecifics. Research on the socio-spatial organization of animals is essential in understanding territoriality, intra- and interspecific competition, and contact rates that influence diverse ecology, including disease transmission between conspecifics and courtship behaviours. We explored these hypotheses with data collected on a solitary carnivore, the cougar (Puma concolor), from 2005 to 2012 in the Southern Yellowstone Ecosystem, Wyoming, USA. We employed 27 annual home ranges for 13 cougars to test whether home range overlap was better explained by land tenure, kinship, resource dispersion or some combination of the three. We found support for both the land tenure and resource dispersion hypotheses, but not for kinship. Cougar sex was the primary driver explaining variation in home range overlap. Males overlapped significantly with females, whereas the remaining dyads (F-F, M-M) overlapped significantly less. In support for the resource dispersion hypothesis, hunting opportunity (the probability of a cougar killing prey in a given location) was often higher in overlapping than in non-overlapping portions of cougar home ranges. In particular, winter hunt opportunity rather than summer hunt opportunity was higher in overlapping portions of female-female and male-female home ranges. Our results may indicate that solitary carnivores are more tolerant of sharing key resources with unrelated conspecifics than previously believed, or at least during periods of high resource availability. Further, our results suggest that the resource dispersion hypothesis, which is typically applied to social species, is applicable in describing the spatial organization of solitary carnivores.

Predation is inherently risky, and Cougars (Puma concolor) are occasionally injured while hunting prey. Between 2001 and 2015, we documented the cause of death of 59 Cougars (22 subadults and 37 adults) in the Southern Yellowstone Ecosystem, Wyoming. Here we report on 2 animals (9% of subadult mortalities) killed as a result of complications after hunting North American Porcupines (Erethizon dorsatum). We also report an observation of a Cougar killed in Venezuela by quills of a Prehensile-tailed Porcupine (Coendou prehensilis). Porcupines may kill and wound more Cougars than previously suspected and may be an important cause of mortality, at least for subadult animals.