Mammalian Carnivores Research Articles

Infection risk associated with carnivore carcasses may govern trophic interactions between maggots and insectivorous passerine birds.

Infection risk by pathogenic agents motivates hosts to avoid using resources with high risks. This, in turn, results in increased availability of these resources for other species that are more tolerant of infections. For instance, carcasses of mammalian carnivores are frequently avoided by conspecific or closely related carnivores, allowing them to be almost exclusively used by maggots. This may lead to novel interactions with other species. This study investigated the consumption of maggots from carnivore carcasses by non-corvid passerines. We successfully monitored 66 raccoon carcasses in Hokkaido, Japan, from 2016 to 2019. Vertebrates only scavenged 14 carcasses before maggot dispersal; the other 52 carcasses produced abundant maggots that regularly fed at least 12 species of non-corvid passerines. Surprisingly, predation occurred at a distance from the carcasses, mainly after maggot dispersal for pupation, despite the higher efficiency of feeding on maggot masses on the carcasses. Birds are likely to reduce the potential risk of infection from the carcass and/or from maggots on the carcasses. Overall, only 1% of maggots were consumed. Our results suggest that necrophagous flies could benefit from the infection risk associated with carnivore carcasses, which may decrease scavenging by other carnivores and constrain maggot consumption by insectivorous birds.

New insights on the ecology and behavior of Machairodus aphanistus (Carnivora, Felidae, Machairodontinae) through the paleopathological study of the fossil sample from the Late Miocene (Vallesian, MN 10) of Cerro de los Batallones (Torrejón de Velasco, Madrid, Spain)

The Late Miocene natural traps of Cerro de los Batallones (Madrid, Spain) have yielded thousands of fossils of vertebrates, mostly carnivoran mammals such as hyaenids, amphicyonids, ailurids, mustelids, ursids, and felids, especially Batallones-1 and Batallones-3. Among these carnivorans, the tiger-sized saber-toothed felid Machairodus aphanistus was the top predator of the association, and one of the most abundant taxa, represented by thousands of fossils, including several examples of bone pathologies that have never been studied. In this work, we carry out a paleopathological analysis of some of these pathologies from the Batallones sample of this large early machairodontine, with a description of the pathological changes that occurred in the affected bones, a possible diagnosis, and the ethological and ecological consequences of the presence of these diseases in the living animal. The pathological sample of M. aphanistus studied here included a calcaneus and a Mc III from Batallones-1, and a mandible from Batallones-3. The fossils were X-rayed, and their pathologies were described and compared to non-pathological bones. The calcaneus showed a bone callus indicative of osteitis/osteomyelitis or a tumor; the mandible had evidence of the development of an abscess located in the left mandibular body; and the Mc III shows a marked osteosclerosis. These injuries affected the hunting ability of these individuals and gradually weakened them, very likely contributing to their final entrapment in the Batallones cavities, where they were attracted by the presence of previously trapped animals.

The reorganization of predator-prey networks over 20 million years explains extinction patterns of mammalian carnivores.

Linking the species interactions occurring at the scale of local communities to their potential impact at evolutionary timescales is challenging. Here, we used the high-resolution fossil record of mammals from the Iberian Peninsula to reconstruct a timeseries of trophic networks spanning more than 20 million years and asked whether predator-prey interactions affected regional extinction patterns. We found that, despite small changes in species richness, trophic networks showed long-term trends, gradually losing interactions and becoming sparser towards the present. This restructuring of the ecological networks was driven by the loss of medium-sized herbivores, which reduced prey availability for predators. The decrease in prey availability was associated with predator longevity, such that predators with less available prey had greater extinction risk. These results not only reveal long-term trends in network structure but suggest that prey species richness in ecological communities may shape large scale patterns of extinction and persistence among predators.

Hematological and plasma profiles and ticks and tick-borne pathogens in wild Formosan black bears (Ursus thibetanus formosanus)

BackgroundThe endangered Formosan black bear (Ursus thibetanus formosanus) is the largest native carnivorous mammal in Taiwan. Diseases, poor management, illegal hunting, and habitat destruction are serious threats to the survival of bear populations. However, studies on the impact of diseases on bear populations are limited. Therefore, this study aimed to establish a database of the hematological and plasma profiles of free-ranging Formosan black bears and investigate the occurrence of ectoparasites, blood parasites, and vector-borne pathogens.MethodsFormosan black bears were captured in Yushan National Park (YNP) and Daxueshan Forest Recreation Area (DSY) in Taiwan. Blood samples were collected from each bear for hematological analysis and plasma biochemistry using a hematology analyzer. Parasites and pathogens were detected using a thin blood smear with Wright–Giemsa staining and polymerase chain reaction (PCR) assay. Additionally, macroscopic ectoparasites were collected from bears to detect blood parasites and other pathogens. Moreover, the relationships between the bear variables (sex, age, and occurrence of parasites or pathogens), ectoparasites, and infectious agents were also analyzed.ResultsIn all, 21 wild bears (14 in YNP and 7 in DSY) were captured and released during the satellite tracking studies. Hematological analysis and plasma biochemistry indicated significant differences in white blood cells (WBC), segments, creatine kinase (CK), and lactate dehydrogenase (LDH) levels between foot snare and culvert-captured bears. Additionally, there were significant differences in total plasma protein (TPP), creatinine, Ca2+, Mg2+, and K+ levels between male and female bears. Moreover, pathogen-infected bears had significantly higher erythrocyte sedimentation rate (ESR; 30 min and 1 h) and globulin levels than uninfected bears. In total, 240 ticks were collected from 13 bears, among which eight adult tick species were identified, including Haemaphysalis flava, Haemaphysalis hystricis, Amblyomma testudinarium, Ixodes ovatus, Dermacentor taiwanensis, Haemaphysalis longicornis, Ixodes acutitarsus, Amblyomma javanense, and nymphs belonging to Haemaphysalis spp. PCR revealed that 13 (61.90%) and 8 (38.10%) bears harbored Hepatozoon ursi and Babesia DNA, respectively. Among the ticks examined, 157 (65.41%) and 128 (53.33%) samples were positive for H. ursi and Babesia, respectively.ConclusionsTo the best of our knowledge, this is the first study to establish a database of the hematological and plasma profiles of wild Formosan black bears and investigate ectoparasite infestation and Hepatozoon and Babesia spp. infection. In conclusion, these findings may serve as a reference for monitoring the health and population of locally endangered bears.Graphical

Global review of anticoagulant rodenticide exposure in wild mammalian carnivores

AbstractAnticoagulant rodenticides (ARs) are an effective tool used to suppress rodent populations in urban and agricultural settings to reduce human disease risk and economic loss, but widespread use has resulted in adverse effects on predators globally. Attention has largely been focused on impacts of ARs on raptors, although there is increasing evidence that mammalian carnivores are also impacted. We conducted a literature review to assess the extent to which ARs have been documented in wild mammalian carnivores globally and identify potential overlap with imperiled carnivores. We found a small but growing body of literature documenting exposure to ARs in 8 Carnivora families, with Mustelidae (64% of studies), Canidae (44%) and Felidae (23%) most represented. At least 11 different AR compounds were documented in carnivores, and authors claimed that exposure caused mortality of at least one individual in 33.9% of species studied. ARs were listed as a threat for 2% of Red List carnivores, although we found that 19% of Red List carnivores had ranges that overlap countries that have documented AR exposure in carnivores. Collectively, our review highlights the need to prioritize conservation attention on the potential role of ARs on global carnivore declines. We suggest (1) expanding AR monitoring and research outside of the northern hemisphere, (2) supporting long‐term AR monitoring to understand the spatial and temporal variation of AR use and exposure risk, (3) expanding research across trophic levels and across the urban–wildland gradient and 4) research to further our understanding of the point at which morbidity and mortality occur.

Competing forces: Subsistence strategies and human-carnivore interactions during the middle to Upper Palaeolithic transition in Northern Iberia

The comparative assessment of dietary choices as part of landscape use strategies deployed by Neanderthal and Anatomically Modern Human populations in Eurasia constitutes a fundamental avenue of Palaeolithic research. The increasing number of taphonomic assessments enables a better understanding of what remains were brought to sites by human hunters versus mammalian carnivores or raptors. A zooarchaeological approach can further elucidate the spatio-temporal dynamics of interaction between carnivores and human populations in terms of landscape use and prey choice during this transitional period. To achieve this objective, we conducted an examination of zooarchaeological and taphonomic data, carnivore indices, and other relevant variables across 36 Middle and Early Upper Palaeolithic sites in northern Iberia. These sites encompass 126 archaeological layers dating from 50,000 to 30,000 years ago. Our comprehensive bibliographic meta-analysis reveals that human occupations by both groups at sites across the region were punctuated by episodes influenced by carnivores. This observation implies that human occupations in northern Iberia during Marine Isotope Stage 3 were generally characterised by instability and limited to short periods, often seasonal in nature. From a zooarchaeological perspective, the combined assessment of taxonomic data, species richness and assemblage diversity highlights that the range and proportion of species acquired by these different human groups are similar, although Anatomically Modern Humans engaged in a sustained trend towards increasing dietary diversification even at sites with assemblages heavily dominated by one taxon.

Evolving landscape and cultural change during the Middle Palaeolithic in Southeast Zagros (Iran): Insights from a micromammal assemblage

The Iranian Zagros is a remarkable zone to study Middle and Upper Palaeolithic human occupations and Tang-e Shikan (Arsanjan) is a strategic cave site which archaeological evidence can be taken as a proxy for the southeast portion. Micromammals have been extensively used as palaeoecological indicators and here we use the assemblage from Tang-e Shikan to infer the landscape and environment that framed and arguably triggered cultural change. A thorough taphonomic analysis was undertaken prior to any interpretation. Fourteen taxa have been identified: two “insectivores” s.l., nine rodents, two lagomorphs, and unidentified chiropterans. The remains would be the digestion by-products of a category 5 opportunistic predator: either an avian raptor or a mammalian carnivore. Our results show that shrubland and grassland dominated the distribution of habitats in the area during the Middle Palaeolithic (MP), followed by moderate rocky, desert, and steppe components, and sparse patches of woodland. The younger period of the MP occupation (NMP: ∼55-45 ka BP) would be somewhat wetter than the older period (OMP: ∼70-55 ka BP). Within a general environmental stability, slight changes between OMP and NMP are reasonably correlated with a shift in certain cultural patterns, as the use of a water reservoir and a stone drainage system during the OMP or the increase of hunting and moderate change in lithic technology and raw material acquisition during the NMP. Our environmental inferences are further supported by palynological data and match a regional trend towards wetter habitats in moving from the MP to the present.

Lethal effects of praziquantel and albendazole, on the cercariae of Echinochasmus sp. (Dietz, 1909) in-vitro.

Echinochasmidae are considered one of the digenean intestinal parasites of carnivorous mammals and humans. Some larvicidal medications, such as praziquantel and albendazole, were employed to interrupt the life cycle of Echinochasmidae, which may cause harmful and serious effects on the domestic fish, ducks, and humans in our ecosystem. Cercariae of Echinochasmus sp. (gymnocephalus type) were harvested by exposing snails to strong artificial illumination. The emerging cercariae were exposed in vitro to different concentrations of praziquantel and albendazole at the same period of incubation 12 h. Using probit analysis in SPSS version 25, the lethal concentrations 50 and 95% were determined. They were 0.036 and 0.82 ppm, respectively, for praziquantel and 5.3 and 9.2 ppm, respectively, for albendazole. The ultrastructural changes using scanning electron microscope on the tegumental surface of the treated cercariae with the two drugs were compared to the untreated cercariae. The untreated cercariae have a pear-shaped body with a long tail. The oral sucker is armed with a spiny collar and decorated with ciliated and unciliated sensory papillae. The cardinal ventral sucker has a thick, muscular wall. The cercarial tail is decorated with parallel longitudinal tegumental processes and spherical, unciliated papillae. In comparisons, cercariae treated with both drugs lost all healthy morphological features, but in varying degrees and effects between the two drugs. Our findings suggest that the use of both drugs can be recommended during the design of control strategies to combat this type of intestinal parasite.

Lynxes and foxes among hyenas, bears and humans. Unit 3 of the Cova del coll Verdaguer Upper Pleistocene site (Barcelona, Iberian Peninsula)

Zooarchaeological and palaeontological assemblages, especially those located in karst cavities, are usually the product of the activity of several taphonomic biological agents. This is also the case of the Upper Pleistocene site of Cova del Coll Verdaguer (Barcelona, Iberian Peninsula), where hyenas accumulated most of the ungulates, bears used the cave to hibernate and for birthing cubs, and humans occasionally visited the cave. The main aim of this study is to investigate the role played by medium-sized mammalian carnivores in the formation of Unit 3 (the Sala Sal de Llop chamber). For this purpose, we analysed Lynx pardinus and Vulpes vulpes remains, on the one hand, and leporid remains, on the other, applying different taphonomic (breakage and surface modifications) zooarchaeological (skeletal parts frequencies, age at death) and spatial methods (GIS, geostatistics, refits). Regarding medium-sized carnivores, the results indicate a predominance of adult individuals, a fairly complete anatomical representation (especially in the case of the lynx), the refitting of several elements (in the case of the lynx, many of them clustered in the same area), and the presence of tooth marks on some remains. This data points to the natural death of these animals inside the cave, and suggests they were subsequently scavenged by other carnivores. With respect to leporids, adult individuals predominate, the most abundant elements are innominate bones and those from the distal segment of the appendicular skeleton, and there is evidence of carnivore damage on several remains. In accordance with these results, the leporid assemblage is interpreted mainly as a non-ingested assemblage caused by the feeding activity of the Iberian lynx and, to a lesser extent, the red fox. Thus, the combination of all these analyses indicates that the medium-sized terrestrial carnivores did not play a merely passive role, but were also accumulators and modifying agents, at least in terms of the leporid remains. Although ungulates are not the focus of this study, we have also discussed the potential role of Iberian lynx and red fox in accumulating and modifying them. This work adds to previously published studies indicating that Cova del Coll Verdaguer is the product of mixed occupations of different carnivore taxa, suggesting that lynxes and foxes used the cave as a safe place to rest, transport their prey and consume it. Therefore, this study will shed more light on the relationships between human groups and different carnivore taxa at Cova del Coll Verdaguer and, by extension, in the European Upper Pleistocene, demonstrating that the study of fossil collections can contribute significantly towards extending our knowledge on past carnivore and human behaviour.

Human habitat modification, not apex scavenger decline, drives isotopic niche variation in a carnivore community.

Top carnivores can influence the structure of ecological communities, primarily through competition and predation; however, communities are also influenced by bottom-up forces such as anthropogenic habitat disturbance. Top carnivore declines will likely alter competitive dynamics within and amongst sympatric carnivore species. Increasing intraspecific competition is generally predicted to drive niche expansion and/or individual specialisation, while interspecific competition tends to constrain niches. Using stable isotope analysis of whiskers, we studied the effects of Tasmanian devil Sarcophilus harrisii declines upon the population- and individual-level isotopic niches of Tasmanian devils and sympatric spotted-tailed quolls Dasyurus maculatus subsp. maculatus. We investigated whether time since the onset of devil decline (a proxy for severity of decline) and landscape characteristics affected the isotopic niche breadth and overlap of devil and quoll populations. We quantified individual isotopic niche breadth for a subset of Tasmanian devils and spotted-tailed quolls and assessed whether between-site population niche variation was driven by individual-level specialisation. Tasmanian devils and spotted-tailed quolls demonstrated smaller population-level isotopic niche breadths with increasing human-modified habitat, while time since the onset of devil decline had no effect on population-level niche breadth or interspecific niche overlap. Individual isotopic niche breadths of Tasmanian devils and spotted-tailed quolls were narrower in human-modified landscapes, likely driving population isotopic niche contraction, however, the degree of individuals' specialisation relative to one another remained constant. Our results suggest that across varied landscapes, mammalian carnivore niches can be more sensitive to the bottom-up forces of anthropogenic habitat disturbance than to the top-down effects of top carnivore decline.

Precipitation seasonality determines the potential distribution of Hyaena hyaena in Saudi Arabia: Towards conservation planning

Hyaena hyaena is a carnivorous mammal that inhabits a broad variety of habitat types and ecological niches, H. hyaena spread in the Arabian Peninsula excluding Rub Al Khali and the desert of Nafud. In Saudi Arabia, it can be found commonly in the western mountains and the open land near agricultural areas such as valleys and lava fields (Harat). However, the H. hyaena is considered to be globally “Near Threatened” (NC) according to (IUCN) Red List as a consequence of a drop in carrion as a result of a reduction in the population of big predators and their prey, eradication practices, and fragmentation and loss of their habitat. The current study seeks to evaluate the distribution of H. hyaena in Saudi Arabia in relation to a number of environmental parameters, as well as assess the possible appropriateness of different habitats for it under climate change scenarios, and provide significant insights for future conservation strategies. The species distribution models (SDMs) tools were employed to map and monitor the distribution of H. hyaena, and then provide a prediction of species distribution patterns. Multicollinearity analysis of the total 19 bioclimatic variables and topographic roughness index resulted in seven uncorrelated variables with VIF < 5, which had been used in the ensemble modeling. The result of our study showed that the decrease in seasonal precipitation will lead to a decrease in the probability of the presence of H. hyaena in Saudi Arabia and The probability of finding H. hyaena in Saudi Arabia decreases as the driest quarter and wettest quarter mean temperature decreases.

Computer vision enables taxon-specific identification of African carnivore tooth marks on bone

Taphonomic works aim at discovering how paleontological and archaeofaunal assemblages were formed. They also aim at determining how hominin fossils were preserved or destroyed. Hominins and other mammal carnivores have been co-evolving, at least during the past two million years, and their potential interactions determined the evolution of human behavior. In order to understand all this, taxon-specific carnivore agency must be effectively identified in the fossil record. Until now, taphonomists have been able to determine, to some degree, hominin and carnivore inputs in site formation, and their interactions in the modification of part of those assemblages. However, the inability to determine agency more specifically has hampered the development of taphonomic research, whose methods are virtually identical to those used several decades ago (lagged by a high degree of subjectivity). A call for more objective and agent-specific methods would be a major contribution to the advancement of taphonomic research. Here, we present one of these advances. The use of computer vision (CV) on a large data set of images of tooth marks has enabled the objective discrimination of taxon-specific carnivore agency up to 88% of the testing sample. We highlight the significance of this method in an interdisciplinary interplay between traditional taphonomic-paleontological analysis and artificial intelligence-based computer science. The new questions that can be addressed with this will certainly bring important changes to several ideas on important aspects of the human evolutionary process.

Intraguild interactions and abiotic conditions mediate occupancy of mammalian carnivores: co‐occurrence of coyotes–fishers–martens

The widespread eradication of large carnivores and subsequent expansion of top mesopredators has the potential to impact species and community interactions with ecosystem‐wide implications. An example of these trophic dynamics is the widespread establishment of coyotes following extirpation of wolves and mountain lions in eastern North America. Here, we examined occupancy of three carnivores in northern New York considering both environmental/habitat factors and interspecific interactions. We estimated the co‐occurrence of coyotes, fishers, and martens from a landscape‐scale winter camera trap survey repeated annually for three years. Martens occurred independently of both coyotes and fishers, while fishers and coyotes displayed positive intraguild interactions that were constant across the landscape. Both marten and fisher first‐order occupancy were driven by a combination of biotic and abiotic factors, with both species displaying positive associations with forest cover but antithetical responses to average snow depth. The integral and antithetical role of snow depth in driving the occurrence of martens (positive) and fishers (negative) in the landscape indicates that future climatic warming could reduce the availability of current spatial refuges for martens created by severe winter conditions. Climate‐driven alterations to established competitive interactions and co‐existence patterns between marten and fisher have critical implications for the species survival and conservation. We provide correlational evidence consistent with the potential for positive top–down effects of dominant mesocarnivores on subordinate species, with fisher occupancy increasing conditional on the presence of coyotes across the landscape. These findings align with the hypothesis that under certain conditions, coyotes may facilitate certain subordinate carnivores. The evidence produced here is consistent with hypotheses on the dynamic nature of trophic niches. We demonstrate the need to consider the interplay between climate, habitat, and interspecific interactions to understand wildlife occupancy patterns and inform wildlife management in a rapidly changing world.

Anthropogenic activities facilitate temporal overlaps and spatial partitions among sympatric canids in a human-modified landscape of Bulgaria

Mammalian carnivores (order Carnivora) occupy higher trophic levels in many terrestrial ecosystems, shaping community structures via direct predation and trophic cascades. The interference competition among sympatric carnivores (i.e., aggression and killing) has a major role in the intraguild interactions in which the large-dominant predators typically constrain behaviors and resource use patterns by exploitative (i.e., resource) competitions as well as the survival of smaller subordinate species by interference (i.e., direct) competitions. The free-roaming dog, Canis lupus familiaris, has been introduced worldwide and the species affects regional biodiversity, including native carnivore species. Using camera trapping, we investigated the temporal and spatial overlaps between the free-roaming dog and two wild canids, the golden jackal (Canis aureus) and the red fox (Vulpes vulpes), in different landscapes of central Bulgaria. We predict their interference interactions, namely that the dog, as the largest competitor, suppresses the golden jackal with intermediate body size, and, in turn, the golden jackal suppresses the smaller red fox. In mountainous forest landscapes where the free-roaming dog was absent or scarce, the golden jackal and red fox partitioned their diel activities, while there were moderate levels of spatial overlap. In agricultural lowlands where dogs were abundant and anthropogenic disturbances were relatively high, all three canids were primarily nocturnal with high temporal overlap, probably owing to human activities (e.g., hunting) in the daytime. The golden jackal was spatially separated from the dog, whereas the red fox spatially overlapped with large dogs. Our results indicated that, in human-modified landscapes with scattered forests and shrubs, spatial partitioning between the free-roaming dog and the golden jackal at fine spatial scales facilitates their sympatry by decreasing the probability of direct encounters. Furthermore, our findings also indicate that spatiotemporal interactions between the golden jackal and the red fox can change in association with various human disturbances, e.g., landscape modifications, human activities, and the introduction of dogs.

Beyond the kill: The allometry of predation behaviours among large carnivores.

The costs of foraging can be high while also carrying significant risks, especially for consumers feeding at the top of the food chain. To mitigate these risks, many predators supplement active hunting with scavenging and kleptoparasitic behaviours, in some cases specializing in these alternative modes of predation. The factors that drive differential utilization of these tactics from species to species are not well understood. Here, we use an energetics approach to investigate the survival advantages of hunting, scavenging and kleptoparasitism as a function of predator, prey and potential competitor body sizes for terrestrial mammalian carnivores. The results of our framework reveal that predator tactics become more diverse closer to starvation, while the deployment of scavenging and kleptoparasitism is strongly constrained by the ratio of predator to prey body size. Our model accurately predicts a behavioural transition away from hunting towards alternative modes of predation with increasing prey size for predators spanning an order of magnitude in body size, closely matching observational data across a range of species. We then show that this behavioural boundary follows an allometric power-law scaling relationship where the predator size scales with an exponent nearing 3/4 with prey size, meaning that this behavioural switch occurs at relatively larger threshold prey body size for larger carnivores. We suggest that our approach may provide a holistic framework for guiding future observational efforts exploring the diverse array of predator foraging behaviours.

The Distribution of Sarcocsytis Species Described by Ungulates-Canids Life Cycle in Intestines of Small Predators of the Family Mustelidae.

Using molecular techniques, we have previously shown that carnivorous mammals of the family Mustelidae might be common definitive hosts for various protozoan Sarcocystis species. In the present study we aimed to unravel whether Sarcocystis species using ungulates as intermediate hosts and canids or felids as definitive hosts can be found in intestine of mustelids. Small intestine samples of 93 individual mustelids of five different species from Lithuania were examined. Sarcocystis species were identified based on species-specific PCR and subsequent cox1 sequencing. Six Sarcocystis species (S. arieticanis, S. bertrami, S. capracanis, S. capreolicanis, S. linearis and S. morae) defined by ungulate-canid life cycle were detected for the first time in small intestines of mustelids. By contrast, the prevalence of Sarcocystis characterised by ungulate-felid life cycle was low (3.2%). Overall, 76% of the examined animals were positive for at least one of the studied Sarcocystis species. Four species, S. arieticanis, S. bertrami, S. capracanis and S. morae were most commonly found, with the detection rate of about 40%. The current finding, in addition to our previous studies, suggests that mustelids play an important role in the spread of various Sarcocystis species.

Detection of prions from spiked and free-ranging carnivore feces

Chronic wasting disease (CWD) is a highly contagious, fatal neurodegenerative disease caused by infectious prions (PrPCWD) affecting wild and captive cervids. Although experimental feeding studies have demonstrated prions in feces of crows (Corvus brachyrhynchos), coyotes (Canis latrans), and cougars (Puma concolor), the role of scavengers and predators in CWD epidemiology remains poorly understood. Here we applied the real-time quaking-induced conversion (RT-QuIC) assay to detect PrPCWD in feces from cervid consumers, to advance surveillance approaches, which could be used to improve disease research and adaptive management of CWD. We assessed recovery and detection of PrPCWD by experimental spiking of PrPCWD into carnivore feces from 9 species sourced from CWD-free populations or captive facilities. We then applied this technique to detect PrPCWD from feces of predators and scavengers in free-ranging populations. Our results demonstrate that spiked PrPCWD is detectable from feces of free-ranging mammalian and avian carnivores using RT-QuIC. Results show that PrPCWD acquired in natural settings is detectable in feces from free-ranging carnivores, and that PrPCWD rates of detection in carnivore feces reflect relative prevalence estimates observed in the corresponding cervid populations. This study adapts an important diagnostic tool for CWD, allowing investigation of the epidemiology of CWD at the community-level.

Genetic characterisation of the domestic cat population (Felis catus) in Valledupar – Cesar using coat markers

The domestic cat (Felis catus) is a small carnivorous mammal belonging to the feline family. It is characterised by significant variability in terms of breeds, with females commonly smaller than males. Cats are one of the most popular pet species worldwide, though there is growing evidence that their large populations are having negative effects on the environment. Cats exhibit noticeable polymorphisms, particularly related to the colour, pattern, and texture of their coat, which can be easily recognised by visual inspection. This makes data collection a straightforward procedure. Cats are an ideal species for population studies because they are cosmopolitan animals and form a panmictic population. Genetic population analyses of cats are essential for understanding the history of their evolution and for developing phylogenetic hypotheses about allele relationships. However, despite the importance of these studies, global information availability is limited and, in some areas, completely absent. The aim of this study wasto determine the level of genetic diversity and structure in domestic cat populations using coat markers in Valledupar, Cesar. Random sampling was conducted between February and September 2022, and 365 adult animals were phenotypically identified in twelve neighbourhoods of the locality. The genes studied included Orange, Agouti, Dilution, Tabby, Long Hair, Siamese, Manx, Spotting White, and Dominant White. The Non-agoutimarker showed the highest frequency (0.740), while the Manx gene exhibited the lowest value. Most of the genetic diversity was found within populations and was limited between populations. Additionally, high gene flow, an excess of heterozygotes, and reduced genetic differentiation between populations were observed. The Spotting White locus showed a departure from Hardy-Weinberg equilibrium. Genetic distance between populations and the obtained dendrogram revealed low significant values, indicating that the populations as a whole are closely related.

Heterozygosity is low where rare color variants in wild carnivores prevail.

Coat color and pattern are a distinguished feature in mammalian carnivores, shaped by climatic cycles and habitat type. It can be expressed in various ways, such as gradients, polymorphisms, and rare color variants. Although natural selection explains much of the phenotypic variation found in the wild, genetic drift and heterozygote deficiency, as prominent in small and fragmented populations, may also affect phenotypic variability through the fixation of recessive alleles. The aim of this study was to test whether rare color variants in the wild could relate to a deficiency of heterozygotes, resulting from habitat fragmentation and small population size. We present an overview of all rare color variants in the order Carnivora, and compiled demographic and genetic data of the populations where they did and did not occur, to test for significant correlations. We also tested how phylogeny and body weight influenced the presence of color variants with phylogenetic generalized linear mixed models (PGLMMs). We found 40 color-variable species and 59 rare color variants. In 17 variable phenotypic populations for which genetic diversity was available, the average A R was 4.18, H O = 0.59, and H E = 0.66, and F IS = 0.086. We found that variable populations displayed a significant reduction in heterozygosity and allelic richness compared to non-variable populations across species. We also found a significant negative correlation between population size and inbreeding coefficients. Therefore, it is possible that small effective size had phenotypic consequences on the extant populations. The high frequency of the rare color variants (averaging 20%) also implies that genetic drift is locally overruling natural selection in small effective populations. As such, rare color variants could be added to the list of phenotypic consequences of inbreeding in the wild.

The gut microbiomes of Channel Island foxes and island spotted skunks exhibit fine-scale differentiation across host species and island populations.

California's Channel Islands are home to two endemic mammalian carnivores: island foxes (Urocyon littoralis) and island spotted skunks (Spilogale gracilis amphiala). Although it is rare for two insular terrestrial carnivores to coexist, these known competitors persist on both Santa Cruz Island and Santa Rosa Island. We hypothesized that examination of their gut microbial communities would provide insight into the factors that enable this coexistence, as microbial symbionts often reflect host evolutionary history and contemporary ecology. Using rectal swabs collected from island foxes and island spotted skunks sampled across both islands, we generated 16S rRNA amplicon sequencing data to characterize their gut microbiomes. While island foxes and island spotted skunks both harbored the core mammalian microbiome, host species explained the largest proportion of variation in the dataset. We further identified intraspecific variation between island populations, with greater differentiation observed between more specialist island spotted skunk populations compared to more generalist island fox populations. This pattern may reflect differences in resource utilization following fine-scale niche differentiation. It may further reflect evolutionary differences regarding the timing of intraspecific separation. Considered together, this study contributes to the growing catalog of wildlife microbiome studies, with important implications for understanding how eco-evolutionary processes enable the coexistence of terrestrial carnivores-and their microbiomes-in island environments.