Three pathogens in sympatric populations of pumas, bobcats, and domestic cats: implications for infectious disease transmission

Anthropogenic landscape change can lead to increased opportunities for pathogen transmission between domestic and non-domestic animals. Pumas, bobcats, and domestic cats are sympatric in many areas of North America and share many of the same pathogens, some of which are zoonotic. We analyzed bobcat, puma, and feral domestic cat samples collected from targeted geographic areas. We examined exposure to three pathogens that are taxonomically diverse (bacterial, protozoal, viral), that incorporate multiple transmission strategies (vector-borne, environmental exposure/ingestion, and direct contact), and that vary in species-specificity. Bartonella spp., Feline Immunodeficiency Virus (FIV), and Toxoplasma gondii IgG were detected in all three species with mean respective prevalence as follows: puma 16%, 41% and 75%; bobcat 31%, 22% and 43%; domestic cat 45%, 10% and 1%. Bartonella spp. were highly prevalent among domestic cats in Southern California compared to other cohort groups. Feline Immunodeficiency Virus exposure was primarily associated with species and age, and was not influenced by geographic location. Pumas were more likely to be infected with FIV than bobcats, with domestic cats having the lowest infection rate. Toxoplasma gondii seroprevalence was high in both pumas and bobcats across all sites; in contrast, few domestic cats were seropositive, despite the fact that feral, free ranging domestic cats were targeted in this study. Interestingly, a directly transmitted species-specific disease (FIV) was not associated with geographic location, while exposure to indirectly transmitted diseases--vector-borne for Bartonella spp. and ingestion of oocysts via infected prey or environmental exposure for T. gondii--varied significantly by site. Pathogens transmitted by direct contact may be more dependent upon individual behaviors and intra-specific encounters. Future studies will integrate host density, as well as landscape features, to better understand the mechanisms driving disease exposure and to predict zones of cross-species pathogen transmission among wild and domestic felids.     

Resource utilization and interspecific relations of sympatric bobcats and coyotes

We used scat analysis and radiotelemetry to characterize use of foods and habitats by sympatric bobcats and coyotes, and evaluated these in the context of spatial and temporal relationships to assess the potential for, and evidence of, interspecific competition. Bobcats and coyotes exhibited broad and overlapping diets. However, diets of the two predators differed in the relative contributions of small and large prey, with bobcats consuming relatively more rodent and lagomorph biomass and coyotes consuming relatively more ungulate biomass. Consumption among rodent prey species was highly correlated between bobcats and coyotes, indicating no evidence of prey partitioning within this group. Habitat selection by the two predators differed slightly at the landscape scale but not within home ranges. Bobcats and coyotes occupied small, overlapping home ranges, such that the likelihood of interspecific encounters (direct or indirect) was high. Bobcats displayed slight avoidance of overlapping coyote core areas during coyote reproductive seasons (winter and spring), when coyotes are typically most territorial (toward conspecifics), but displayed slight attraction during times of year when coyotes were not engaged in reproductive activities. Relative to coyotes, which were strongly nocturnal, diel activity patterns of bobcats were more diurnal and variable. However, activity patterns were not inversely correlated. Overall, these predators appeared to use resources independently and we found little evidence of negative interactions. Differences in resource use by bobcats and coyotes appeared to relate to fundamental niche differences as opposed to competition-related resource partitioning.     

Interspecific interactions between wild felids vary across scales and levels of urbanization

Ongoing global landscape change resulting from urbanization is increasingly linked to changes in species distributions and community interactions. However, relatively little is known about how urbanization influences competitive interactions among mammalian carnivores, particularly related to wild felids. We evaluated interspecific interactions between medium‐ and large‐sized carnivores across a gradient of urbanization and multiple scales. Specifically, we investigated spatial and temporal interactions of bobcats and pumas by evaluating circadian activity patterns, broad‐scale seasonal interactions, and fine‐scale daily interactions in wildland–urban interface (WUI), exurban residential development, and wildland habitats. Across levels of urbanization, interspecific interactions were evaluated using two‐species and single‐species occupancy models with data from motion‐activated cameras. As predicted, urbanization increased the opportunity for interspecific interactions between wild felids. Although pumas did not exclude bobcats from areas at broad spatial or temporal scales, bobcats responded behaviorally to the presence of pumas at finer scales, but patterns varied across levels of urbanization. In wildland habitat, bobcats avoided using areas for short temporal periods after a puma visited an area. In contrast, bobcats did not appear to avoid areas that pumas recently visited in landscapes influenced by urbanization (exurban development and WUI habitat). In addition, overlap in circadian activity patterns between bobcats and pumas increased in exurban development compared to wildland habitat. Across study areas, bobcats used sites less frequently as the number of puma photographs increased at a site. Overall, bobcats appear to shape their behavior at fine spatial and temporal scales to reduce encounters with pumas, but residential development can potentially alter these strategies and increase interaction opportunities. We explore three hypotheses to explain our results of how urbanization affected interspecific interactions that consider activity patterns, landscape configuration, and animal scent marking. Altered competitive interactions between animals in urbanized landscapes could potentially increase aggressive encounters and the frequency of disease transmission.     

Habitat Use by Sympatric Jaguars and Pumas Across a Gradient of Human Disturbance in Belize

Jaguars (Panthera onca) and pumas (Puma concolor) are sympatric across the entire jaguar range, where they coexist in increasingly fragmented landscapes under threat of persecution mainly in response to livestock predation. Pumas are known to inhabit a greater variety of natural habitats than jaguars, but little is known about the influence of anthropogenic factors on the coexistence of these two similar-sized cats. This study compares habitat use of jaguars and pumas in Belize, Central America, using 1380 jaguar and puma photo captures from 3 yr of camera trapping, comprising 64–74 individual jaguars and an unknown number of pumas. Jaguars and pumas did not differ in their use of a large block of relatively homogenous secondary rain forest. However, pumas were scarce outside this forest block, whereas jaguars were detected throughout the human-influenced landscape. Reasons for this discrepancy may include differential tolerance to human disturbance, and resource limitation for pumas outside the forest block. Intra-specific variation in jaguar activity in the form of sex-dependent habitat use was detected across the landscape. Male jaguars were detected at more locations than female jaguars and more frequently at each location, with a declining difference from a 50-fold greater detection in the protected forest, through forest buffer, savannah, pastures, to negligible difference in the disturbed forest.     

Habitat avoidance of an introduced weed by native lizards

Abstract: Rubber vine (Cryptostegia grandiflora) is an environmental weed that frequently invades riparian habitats in northern Australia. I examined the habitat use of lizards in riparian and woodland environments comprised of native and rubber vine vegetation. Rubber vine was a major component of vegetation in the riparian habitat (approximately 40%), but only a minor component of woodland habitat (approximately 5%). Of 132 lizards, none were observed using rubber vine vegetation in riparian habitats, significantly less than expected, and only one lizard was observed in rubber vine vegetation in the woodland habitat. As rubber vine vegetation contains features that superficially resemble native habitat used by lizards, such as leaf litter, the avoidance of rubber vine by lizards suggests that rubber vine has underlying characteristics that create a suboptimal environment for lizards.     

Frequent transmission of immunodeficiency viruses among bobcats and pumas

With the exception of human immunodeficiency virus (HIV), which emerged in humans after cross-species transmissions of simian immunodeficiency viruses from nonhuman primates, immunodeficiency viruses of the family Lentiviridae represent species-specific viruses that rarely cross species barriers to infect new hosts. Among the Felidae, numerous immunodeficiency-like lentiviruses have been documented, but only a few cross-species transmissions have been recorded, and these have not been perpetuated in the recipient species. Lentivirus seroprevalence was determined for 79 bobcats (Lynx rufus) and 31 pumas (Puma concolor) from well-defined populations in Southern California. Partial genomic sequences were subsequently obtained from 18 and 12 seropositive bobcats and pumas, respectively. Genotypes were analyzed for phylogenic relatedness and genotypic composition among the study set and archived feline lentivirus sequences. This investigation of feline immunodeficiency virus infection in bobcats and pumas of Southern California provides evidence that cross-species infection has occurred frequently among these animals. The data suggest that transmission has occurred in multiple locations and are most consistent with the spread of the virus from bobcats to pumas. Although the ultimate causes remain unknown, these transmission events may occur as a result of puma predation on bobcats, a situation similar to that which fostered transmission of HIV to humans, and likely represent the emergence of a lentivirus with relaxed barriers to cross-species transmission. This unusual observation provides a valuable opportunity to evaluate the ecological, behavioral, and molecular conditions that favor repeated transmissions and persistence of lentivirus between species.     

Seasonal occupancy of sympatric larger carnivores in the southern San Andres Mountains,south-central New Mexico,USA

We investigated factors facilitating coexistence of pumas (Puma concolor), coyotes (Canis latrans), and bobcats (Lynx rufus) in the arid San Andres Mountains of south-central New Mexico, during the season (winter and spring, prior to the annual monsoon) of greatest resource stress. We established a camera-trapping grid in the San Andres, 2007–2011, and modeled occupancy of the three carnivores as a function of habitat, prey, and presence of the other carnivore species. Species interaction factors were >1.3 for each pair of carnivores, and the presence of the other carnivore species never significantly influenced occupancy of any other carnivore. Similarly, occupancy of the San Andres landscape was positively correlated among all carnivores. Occupancy of pumas was most influenced by proximity of water; coyote occupancy was influenced by terrain ruggedness and presence of medium (primarily lagomorph) prey, and bobcat occupancy was influence primarily small prey and proximity to water. The three carnivores also did not show temporal partitioning in use of habitats. Rather than segregation driven by competition, predation, or despotism, our results appeared to reflect preferences for differing habitat characteristics between ambush and cursorial predators and preferred habitats for travel.     

Anticoagulant Exposure and Notoedric Mange in Bobcats and Mountain Lions in Urban Southern California

Abstract: Humans introduce many toxicants into the environment, the long-term and indirect effects of which are generally unknown. We investigated exposure to anticoagulant rodenticides and evaluated the association between notoedric mange, an ectoparasitic disease, and anticoagulant exposure in bobcats (Lynx rufus) and mountain lions (Puma concolor) in a fragmented urban landscape in southern California, USA. Beginning in 2002, an epizootic of notoedric mange, a disease previously reported only as isolated cases in wild felids, in 2 years reduced the annual survival rate of bobcats from 0.77 (5-yr average) to 0.28. Anticoagulants were present in 35 of 39 (90%) bobcats we tested, multiple compounds were present in 27 of these 35 (77%), and total toxicant load was positively associated with the use of developed areas by radiocollared animals. Mange-associated mortality in bobcats showed a strong association with anticoagulant exposure, as 19 of 19 (100%) bobcats that died with severe mange were also exposed to the toxicants, and for bobcats with anticoagulant residues >0.05 ppm, the association with mange was highly significant (X² = 10.36, P = 0.001). We speculate that concomitant elevated levels of rodenticide exposure may have increased the susceptibility of bobcats to advanced mange disease. Bobcats were locally extirpated from some isolated habitat patches and have been slow to recover. In 2004, 2 adult mountain lions died directly from anticoagulant toxicity, and both animals also had infestations of notoedric mange, although not as advanced as in the emaciated bobcats that died with severe disease. Two other mountain lions that died in intraspecific fights also exhibited exposure to 2-4 different anticoagulants. These results show that the effects of secondary poisoning on predators can be widespread, reach even the highest-level carnivores, and have both direct and possibly indirect effects on mortality. Further research is needed to investigate the lethal and sub-lethal effects of anticoagulants and other toxicants on wildlife in terrestrial environments.     

Differential impact of landscape transformation on pumas (Puma concolor) and jaguars (Panthera onca) in the Upper Paraná Atlantic Forest

Aim Jaguars and pumas, being similar in size and behaviour, are the largest felids of the Neotropics. However, pumas appear to be more resistant to human impacts. Our objective was to compare the response of both species with human impacts at a regional scale in a highly modified region where both species had continuous distribution in the past. Location The Upper Parana Atlantic Forest (UPAF). Methods Pumas and jaguars presence‐only data were used in an Ecological Niche Factor Analysis (ENFA). From the total number of records, we resampled 95 records of each species 10 times to characterize and compare their habitat requirements, built habitat‐suitability maps and examined interspecific differences in niche parameters related to present landscape characteristics. Results Both species showed high dependence on native forest and habitat protection, and low tolerance to anthropogenic environments. However, jaguars showed higher differences between their optimal habitat and the available landscape (mean ± SD; marginality M = 2.290 ± 0.072) and lower tolerance to deviations from their optimal habitat (tolerance T = 0.596 ± 0.013) than pumas (M = 1.358 ± 0.067, P < 0.001; T = 0.742 ± 0.022, P < 0.001). Although their niches highly overlapped (Pianka’s O = 0.746 ± 0.069), pumas’ higher tolerance resulted in a larger area covered by suitable patches of habitat with higher connectivity. All jaguar‐suitable areas were also suitable for pumas; however, 44 ± 8% of puma‐suitable areas were unsuitable or marginal for jaguars. Main conclusions Pumas showed more tolerance than jaguars to human impacts at a regional scale in the UPAF, a pattern also observed at local and continental scales. Although the proximate factors responsible for the differential response of pumas to human‐altered environments seem to be similar at all spatial scales (e.g. broader trophic niche than jaguars), the resultant spatial configuration of suitable habitat at a regional scale might be another important factor determining puma persistence and higher jaguar demands on conservation efforts.     

Differential Use of Trails by Forest Mammals and the Implications for Camera-Trap Studies: A Case Study from Belize

Relative abundance indices are often used to compare species abundance between sites. The indices assume that species have similar detection probabilities, or that differences between detection probabilities are known and can be corrected for. Indices often consist of encounter frequencies of footprints, burrows, markings or photo captures along trails or transect lines, but the assumption of equal detection probabilities is rarely validated. This study analyzes detection probabilities of a range of Neotropical mammals on trails in dense secondary forests, using camera-trap and track data. Photo captures of the two large cats, jaguars ( Panthera onca ) and pumas ( Puma concolor ), were correlated solely with trail variables, while photo captures of their potential prey species had no correlation or negative correlation with trail variables. The Neotropical mammals varied greatly in their tendency to follow or cross trails based on footprints surveys. This indicates that camera locations on trails will have varying detection probability for these Neotropical mammals. Even the two similar-sized jaguars and pumas, occupying relatively similar niches, differed subtly in their use of trails. Pumas followed trails more completely while jaguars were more likely to deviate from trails. The ecological significance of these findings is that jaguars seem to be more willing to use the forest matrix away from trails than do pumas. We conclude that trail-based indices, such as photographic captures or tracks along trails, are not appropriate for comparison between Neotropical species, and not even between relatively similar species like jaguars and pumas.     

Competition and intraguild predation among three sympatric carnivores

We examined the relative roles of dominance in agonistic interactions and energetic constraints related to body size in determining local abundances of coyotes (Canis latrans, 8-20 kg), gray foxes (Urocyon cinereoargenteus, 3-5 kg) and bobcats (Felis rufus, 5-15 kg) at three study sites (hereafter referred to as NP, CP, and SP) in the Santa Monica Mountains of California. We hypothesized that the largest and behaviorally dominant species, the coyote, would exploit a wider range of resources (i.e., a higher number of habitat and/or food types) and, consequently, would occur in higher density than the other two carnivores. We evaluated our hypotheses by quantifying their diets, food overlap, habitat-specific abundances, as well as their overall relative abundance at the three study sites. We identified behavioral dominance of coyotes over foxes and bobcats in Santa Monica because 7 of 12 recorded gray fox deaths and 2 of 5 recorded bobcat deaths were due to coyote predation, and no coyotes died as a result of their interactions with bobcats or foxes. Coyotes and bobcats were present in a variety of habitats types (8 out of 9), including both open and brushy habitats, whereas gray foxes were chiefly restricted to brushy habitats. There was a negative relationship between the abundances of coyotes and gray foxes (P=0.020) across habitats, suggesting that foxes avoided habitats of high coyote predation risk. Coyote abundance was low in NP, high in CP, and intermediate in SP. Bobcat abundance changed little across study sites, and gray foxes were very abundant in NP, absent in CP, and scarce in SP; this suggests a negative relationship between coyote and fox abundances across study sites, as well. Bobcats were solely carnivorous, relying on small mammals (lagomorphs and rodents) throughout the year and at all three sites. Coyotes and gray foxes also relied on small mammals year-round at all sites, though they also ate significant amounts of fruit. Though there were strong overall interspecific differences in food habits of carnivores (P<0.0001), average seasonal food overlaps were high due to the importance of small mammals in all carnivore diets [bobcat-gray fox: 0.79ǂ.09 (SD), n=4; bobcat-coyote: 0.69ǂ.16, n=6; coyote-gray fox: 0.52ǂ.05, n=4]. As hypothesized, coyotes used more food types and more habitat types than did bobcats and gray foxes and, overall, coyotes were the most abundant of the three species and ranged more widely than did gray foxes. We propose that coyotes limit the number and distribution of gray foxes in Santa Monica Mountains, and that those two carnivores exemplified a case in which the relationship between their body size and local abundance is governed by competitive dominance of the largest species rather than by energetic equivalences. However, in the case of the intermediate-sized bobcat no such a pattern emerged, likely due to rarity or inconsistency of agonistic interactions and/or behavioral avoidance of encounters by subordinate species.     

Competitive interactions between felid species may limit the southern distribution of bobcats Lynx rufus

Bobcats are opportunistic felids occurring in a diverse range of habitats and with a widespread distribution from southern Canada to southern Mexico. To explore why the bobcat's distribution stops at the Isthmus of Tehuantepec, we modelled the ecological niches, projected as potential distributions, of the felid community (bobcat Lynx rufus, puma Puma concolor, jaguar Panthera onca, margay Leopardus wiedii, jaguarundi Herpailurus yagouaroundi, and ocelot Leopardus pardalis) in southern Mexico, using occurrence data, environmental maps, the computer algorithm GARP, and a GIS platform. The resulting geographical projection of the ecological niche of bobcats extends south of the Isthmus of Tehuantepec, suggesting that ecological conditions exist for the establishment of populations. The overlap of the modelled distribution of the bobcat was large with that of the puma (97%), but low with that of the ocelot (44%), margay (46%), jaguar (49%), and jaguarundi (52%), the latter three having relatively similar size and feeding habits to bobcats. Moreover, an independent analysis computing a geographic co‐occurrence index showed a similar trend of geographic avoidance (values 0.15), while all felids, except bobcats, showed a geographic co‐occurrence in southern Mexico (values ranging from ?1.91 to 4.71). The Isthmus of Tehuantepec, a lowland region with subtropical habitat, is unlikely to serve as a geographic and ecological barrier to bobcats. As mammal inventories have been conducted for over a century in this region with no records of bobcats, it is unlikely that bobcats are present but have just not been seen. Fossil records also provide no support for the presence of bobcats in that region in the past. Thus, competitive interactions with other felid species appear important in limiting the southern distribution of bobcats, preventing dispersal to a suitable but geographically reduced area south of the Isthmus of Tehuantepec.     

Using occupancy models to investigate space partitioning between two sympatric large predators, the jaguar and puma in central Brazil

Coexistence of sympatric species is mediated by resource partitioning. Pumas occur sympatrically with jaguars throughout most of the jaguar's range but few studies have investigated space partitioning between both species. Here, camera trapping and occupancy models accounting for imperfect detection were employed in a Bayesian framework to investigate space partitioning between the jaguar and puma in Emas National Park (ENP), central Brazil. Jaguars were estimated to occupy 54.1% and pumas 39.3% of the sample sites. Jaguar occupancy was negatively correlated with distance to water and positively correlated with the amount of dense habitat surrounding the camera trap. Puma occupancy only showed a weak negative correlation with distance to water and with jaguar presence. Both species were less often present at the same site than expected under independent distributions. Jaguars had a significantly higher detection probability at cameras on roads than at off-road locations. For pumas, detection was similar on and off-road. Results indicate that both differences in habitat use and active avoidance shape space partitioning between jaguars and pumas in ENP. Considering its size, the jaguar is likely the competitively dominant of the two species. Owing to its habitat preferences, suitable jaguar habitat outside the park is probably sparse. Consequently, the jaguar population is likely largely confined to the park, while the puma population is known to extend into ENP's surroundings.     

When carnivores collide: a review of studies exploring the competitive interactions between bobcats Lynx rufus and coyotes Canis latrans

1. Bobcats Lynx rufus and coyotes Canis latrans are two widespread mesopredators with a complex history of sympatry. The competitive interactions between these species are of interest to biologists due to the furbearer status of bobcats, the recent range expansion of coyotes, and the recolonisation of several parts of North America by bobcats following their extirpation. Although studies exploring the dynamics and competition between bobcats and coyotes span decades, there is a lack of understanding regarding what factors influence exploitative or interference competition, and what methodologies are conducive to identifying these types of competition.
2. We gathered a comprehensive list of research papers (n = 41) exploring bobcat–coyote competitive interactions in North America. From them, we collected the following: study site characteristics, number and types of research methods, number and types of metrics explored, history of sympatry of the two species at the study location, presence of apex predators, and documentation of interference and/or exploitative competition.
3. Using generalised linear models, we determined that interference competition between bobcats and coyotes was observed primarily in open habitat. However, habitat heterogeneity, the number of research methods and metrics used, presence of an apex predator, and history of sympatry could not be used to predict the occurrence of interference competition. Studies that included diet overlap were less likely to observe interference competition than studies that used other metrics to infer competition.
4. Competitive interactions between coyotes and bobcats are largely a function of prey availability. Our findings suggest that habitat type may be a surrogate for prey availability, which many researchers mention, but do not explicitly measure. Future studies investigating bobcat–coyote interactions should include the quantification of prey densities to gain a more comprehensive understanding of the system at large, and should avoid using solely diet or habitat overlap as metrics to assess competition.

     

Relative value of riparian woodlands in landscapes with different forest cover for medium-sized Iberian carnivores

This study analyses the role of riparian woodland in the conservation of five common carnivore species as compared with other non-riparian habitats according to woodland cover on the landscape scale (>60, 20–35 and <15% on 20 × 20-km surface area). I hypothesised that the importance of riparian woodlands in carnivore conservation on the regional scale would be greater in landscapes with low forest cover than in those with intermediate or high forest cover. To test this hypothesis, in each landscape type I sampled five riparian forests and 10–15 non-riparian habitats and recorded species richness and frequency of occurrence (number of sampled sites with species presence/total sampled sites) in both habitat types. The presence of (or use by) species at each particular sampling site was recorded using sign-surveys (search for scats and badger dens). The relative importance of riparian and non-riparian habitats in each landscape type was analysed by comparing species richness and frequency of occurrence for each species. Comparison of species richness and frequency of occurrence between landscape types indicate that riparian woodlands are important habitats in all landscape contexts. However, in accordance with the initial hypothesis, riparian woodlands are essential for carnivore conservation in the most deforested areas. Any agricultural or development policy should take into account the need to maintain and preserve riparian woodlands in landscapes, especially in intensively cultivated landscapes.     

A non-invasive faecal survey for the study of spatial ecology and kinship of solitary felids in the Viruá National Park,Amazon Basin

Jaguars and pumas are the largest felids in the Americas. Information about these two species is scarce, especially where both species are sympatric. We studied the use and selection of macrohabitats, spatial segregation and kinship in jaguars and pumas in the Viruá National Park (Amazonian lowlands) by non-invasive genetic analyses of faecal samples. Seven different jaguars (six males and one female) and nine different pumas (five males and four females) were identified. We found space use segregation between the two species, with pumas using mostly forested habitats and jaguars using open habitats slightly more than the forested ones. This result is unexpected, since previous studies have found that pumas favour more open habitats than jaguars. The results suggest that jaguars use the areas in a more random manner, corresponding to the habits of a dominant generalist species, whereas pumas use the area to reduce encounter rates with jaguars. Nevertheless, both species mainly used areas near upland forest-flooding habitats. Some kinship categories were supported with a p < 0.05 in 57 and 83% of the pair comparisons between the identified jaguars and the identified pumas, respectively. Non-invasive genetic analysis of faeces was useful to study the spatial ecology of solitary, rare and cryptic species in the Amazon.     

Puma and Human Spatial and Temporal Use of a Popular California State Park

Abstract: Because of increasing concerns about puma (Puma concolor) attacks on people and the desire to minimize dangerous puma-human encounters while conserving puma populations, we examined spatial and temporal relationships between pumas and people that used Cuyamaca Rancho State Park (CRSP), California, USA. From 2001 to 2003, we studied 10 adult pumas outfitted with Global Positioning System collars. Although number of visitors to CRSP was increasing, no dangerous puma-human encounters were reported during our study. Male and female pumas typically moved short distances during the day (mean of means of individual hourly movements = 168 m and 131 m each hr, respectively) and moved the most at night (mean of means = 690 m and 390 m each hr, respectively). Of 10 pumas, 9 were least active during the day and most active during the evening or at night. In contrast, most visitor use of trails (x̄ = 85%) occurred during the day. Based on puma and human activity patterns, risk of a puma-human encounter was greatest during the evening. Puma prey caches were randomly distributed in relation to trails and park facilities; however, 8 of 33 caches were still within 100 m of a trail and 2 were within 300 m of a facility. Individual puma behavior relative to human activity areas was variable. Some pumas appeared to temporally avoid human activity areas; others used the park randomly in relation to human activity areas; none appeared to be attracted to human activity areas. Pumas that did not show detectable responses to human activity may have been exhibiting some level of habituation; if so, this level of habituation did not result in puma-human conflicts. When human activity peaked during the day, adult male and female pumas were within 100 m of a trail an average of 9% and 19% of the time they were located in the park, respectively. Thus, there were opportunities for puma-human encounters. Management personnel can take a proactive approach to deal with puma-human interactions through education and protocols that help to minimize probability of conflicts; this may provide the best chance for a continued puma presence in habitat used by pumas and people.     

EVOLUTION OF HORNS IN UNGULATES: ECOLOGY AND PALEOECOLOGY

(1) The savanna ungulate faunas of the North American Miocene were broadly similar to those of present-day East Africa in terms of overall morphological and taxonomic diversity. However, the predominant ungulates of the African faunas are bovids, which possess bony horns that are primitively sexually dimorphic in their occurrence. The predominant ungulates of the North American Tertiary were equids, camelids and oreodonts, which all lacked horns. A limited number of horned ruminants were present, but these were largely Miocene immigrants from Eurasia. Horns were also absent from the large-bodied herbivores in the endemic faunas of South America and Australia. (2) The absence of horns in equids and tylopod artiodactyls is unlikely to be due to genetic insufficiency. Bony horns were present in brontotheres, which were closely related to equids, and in protoceratids, which were closely related to camelids. Nasal horns were present in one oreodont genus. (3) Studies on living ungulates show that a strong correlation exists between habitat type, feeding behaviour, social behaviour and morphology. It is possible to use the morphological remains of extinct ungulates to reconstruct the types of feeding and social behaviour, and to use the distribution of morphologies and body sizes in a community of mammals, in conjunction with geological and paleobotanical evidence, to reconstruct the type of habitat. (4) The importance of the post-Eocene climatic changes to the history of mammalian evolution is stressed. Continents at higher latitudes have become increasingly seasonal in terms of temperature and rainfall since the equable global conditions of the early Tertiary. Savanna mosaic were the predominant biome in North America by the early Miocene, and in Eurasia by the middle Miocene. Living temperate-latitude species of ungulates may not be a reliable guide for the assessment of the interrelationship between behaviour and morphology in an evolutionary perspective, as their behaviour may have been recently adapted to a habitat type that has only been in existence since the Pleistocene. (5) The primitive condition in eupecorans and protoceratids is the absence of horns, with the presence of large sabre-like canines in the males. The first horned members of these divisions had horns in the males only. Small present-day antelope, where horns may also be present in the females of the species, are probably secondarily small. (6) Horns were acquired independently in ruminant artiodactyls at least three times, and a maximum number of seven times is not unlikely. In each case, horns first appeared at a critical body weight of about 18 kg, and in correlation with a change in habitat from closed to open woodland. (7) Horns in living ruminants are associated with territorial defence by males holding exclusive feeding and reproductive territories in woodland habitats. Such behaviour in present-day antelope is correlated with a body size of greater than 15 kg and a folivorous diet. It is argued that horns evolved in ruminant artiodactyls on the adoption of this type of territorial behaviour once the critical combination of body size, diet and habitat type had been attained in their evolution from small, essentially frugivorous, forest-dwelling animals. (8) Perissodactyls never evolved sexually dimorphic bony horns of the type seen in ruminant artiodactyls. This is because their foraging and digestive strategies necessitate a larger daily intake of food. In a woodland habitat they were never able to adopt a feeding area small enough to make exclusive territory maintenance an economical proposition. Territory holding in male perissodactyls is seen, but under the opposite conditions of habitat to territorial behaviour in ruminant artiodactyls. (9) Study of the morphology and paleoecology of oreodonts suggests that they were woodland herd-forming browsers with exclusively folivorous diets. They probably had some forestomach fermentation, but did not chew the cud. Similar studies of Tertiary camelids suggest that they were predominantly selective browsers eating herbage at a low level in open country and formed mixed-sex feeding groups. These combinations of feeding and social behaviour suggest a more open structure of the mid-Tertiary habitat in North America than in Eurasia. (10) Studies of the behaviour and morphology of living members of the Ruminantia, and of the morphology and paleoecology of their fossil ancestors, suggest that they were primitively tree browsers living in closed woodland habitats. Such habitats were abundant in the Old World, but in limited supply in North America during the Oligocene, where the protoceratids were the only ungulates to parallel the eupecoran type of feeding and social behaviour. South America appears to have had an even more open habitat in the Oligocene than North America, and no parallel to the eupecorans was seen amongst the indigenous ungulates. The radiation of the Bovidae into open grassy habitats in the Pliocene may have been dependent on the immigration of grazing equids into the Old World. (11) I conclude that there was a difference in habitat structure between North America and the Old World during the Tertiary. The food resources in North America were more widely dispersed, and this may have been the result of the trees being more widely spaced. A possible causal mechanism for this was the stable land mass of the North American continent during the Tertiary, resulting in a more continental climate, with a more severe effect of the post-Eocene seasonality on the vegetation. The faunal record of the two continents also implied a greater density of trees in the Old World. (12) Thus most endemic North American ruminants did not evolve horns because, at the critical combination of body size and diet seen in the evolution of horns in the Old World ruminants, the dispersal of the food resources within the vegetation was too great for an effective home range to be maintained as an exclusive territory. (13) Attention is drawn to the dangers of constructing evolutionary stories about living animals without primary reference to the fossil record to see if the hypotheses are upheld, and of assuming that fossil animal communities can be made to fit models of existing communities.     

Variability in assays used for detection of lentiviral infection in bobcats (Lynx rufus), pumas (Puma concolor), and ocelots (Leopardus pardalis)

Although lentiviruses similar to feline immunodeficiency virus (FIV) are known to infect numerous felid species, the relative utility of assays used for detecting lentiviral infection has not been compared for many of these hosts. We tested bobcats (Lynx rufus), pumas (Felis concolor), and ocelots (Leopardus pardalis) for exposure to lentivirus using five different assays: puma lentivirus (PLV), African lion lentivirus (LLV), and domestic cat FIV-based immunoblots, a commercially available enzyme-linked immunosorbent assay (ELISA) kit, and nested polymerase chain reaction (PCR). Puma lentivirus immunoblots identified more seropositive individuals than the other antibody-detection assays. The commercial ELISA provided a fair ability to recognize seropositive samples when compared with PLV immunoblot for screening bobcats and ocelots, but not pumas. Polymerase chain reaction identified fewer positive samples than PLV immunoblot for all three species. Immunoblot results were equivalent whether the sample tested was serum, plasma, or whole blood. The results from this study and previous investigations suggest that the PLV immunoblot has the greatest ability to detect reactive samples when screening wild felids of North America and is unlikely to produce false positive results. However, the commercial ELISA kit may provide an adequate alternative for screening of some species and is more easily adapted to field conditions.