Carnivores play key roles in maintaining ecosystem structure and function as well as ecological processes. Understanding how sympatric species coexist in natural ecosystems is a central research topic in community ecology and biodiversity conservation. In this study, we explored intra- and interspecific niche partitioning along spatial, temporal, and dietary niche partitioning between apex carnivores (wolf Canis lupus, snow leopard Panthera uncia, Eurasian lynx Lynx lynx) and mesocarnivores (Pallas\'s cat Otocolobus manul, red fox Vulpes vulpes, Tibetan fox Vulpes ferrilata) in Qilian Mountain National Park, China, using camera trapping data and DNA metabarcoding sequencing data. Our study showed that apex carnivore species had more overlap temporally (coefficients of interspecific overlap ranging from 0.661 to 0.900) or trophically (Pianka\'s index ranging from 0.458 to 0.892), mesocarnivore species had high dietary overlap with each other (Pianka\'s index ranging from 0.945 to 0.997), and apex carnivore and mesocarnivore species had high temporal overlap (coefficients of interspecific overlap ranging from 0.497 to 0.855). Large dietary overlap was observed between wolf and snow leopard (Pianka\'s index = 0.892) and Pallas\'s cat and Tibetan fox (Pianka\'s index = 0.997), suggesting the potential for increased resource competition for these species pairs. We concluded that spatial niche partitioning is likely to key driver in facilitating the coexistence of apex carnivore species, while spatial and temporal niche partitioning likely facilitate the coexistence of mesocarnivore species, and spatial and dietary niche partitioning facilitate the coexistence between apex and mesocarnivore species. Our findings consider partitioning across temporal, spatial, and dietary dimensions while examining diverse coexistence patterns of carnivore species in Qilian Mountain National Park, China. These findings will contribute substantially to current understanding of carnivore guilds and effective conservation management in fragile alpine ecosystems.

Wolves are commonly housed in zoological institutions and captive breeding facilities that are essential for maintaining genetic diversity and for the recovery of declining populations. Neoplasia is a common cause of mortality in wolves, but hemangiosarcoma has not previously been described. This condition was diagnosed in four red wolves (Canis rufus) and two gray wolves (Canis lupus) housed at five different institutions between 2008 and 2018. Animals were 11-16 yr of age at the time of presentation. Clinical signs included loss of body condition, abdominal distension, lethargy, weakness, ataxia, and hyporexia. Three animals were mildly anemic. All animals were humanely euthanized within an average of 3 d from onset of clinical signs. Two animals had primary splenic tumors, two had pelvic tumors with one originating from the aorta, and one had a cranial mediastinal mass. Diagnosis was made on postmortem histologic examination in all cases. Four wolves had evidence of metastases with foci in the lungs, lymph nodes, mesentery, liver, subcutis/skeletal muscle, kidney, adrenal, and thyroid gland. Hemangiosarcoma should be considered in geriatric wolves presenting with nonspecific signs, particularly if abdominal distension, free peritoneal fluid, or anemia is present.

For prey, movement synchrony represents a potent antipredator strategy. Prey, however, must balance the costs and benefits of using conspecifics to mediate risk. Thus, the emergent patterns of risk-driven sociality depend on variation in space and in the predators and prey themselves. We applied the concept of predator-prey habitat domain, the space in which animals acquire food resources, to test the conditions under which individuals synchronize their movements relative to predator and prey habitat domains. We tested the response of movement synchrony of prey to predator-prey domains in two populations of ungulates that vary in their gregariousness and predator community: (i) elk, which are preyed on by wolves; and (ii) caribou, which are preyed on by coyotes and black bears. Prey in both communities responded to cursorial predators by increasing synchrony during seasons of greater predation pressure. Elk moved more synchronously in the wolf habitat domain during winter and caribou moved more synchronously in the coyote habitat domains during spring. In the winter, caribou increased movement synchrony when coyote and caribou domains overlapped. By integrating habitat domains with movement ecology, we provide a compelling argument for social behaviours and collective movement as an antipredator response. This article is part of the theme issue \'The spatial-social interface: A theoretical and empirical integration\'.

Trichinella spp. are cosmopolitan parasites that infect a wide range of hosts, with wildlife being the main reservoir of these zoonotic nematodes, especially red foxes (Vulpes vulpes) and wolves (Canis lupus) due to their apex position in the food chain in most European countries. The aim of this study is to investigate the prevalence of Trichinella spp. in these wild canids and their epidemiological role in the Campania region (southern Italy). From 2017 to 2023, the carcasses of red foxes (n = 352) and wolves (n = 41) were collected as part of a health surveillance plan. Muscle samples were analysed individually by artificial digestion and four (1.1%) red foxes and nine (21.9%) wolves tested positive for Trichinella britovi. All Trichinella isolates were identified as T. britovi by multiplex PCR. Statistically significant differences in prevalence were found by province (p-value = 0.05) for red foxes and sampling years (p-value = 0.01) for wolves. The prevalence was lower in red foxes than in wolves, probably due to the longer life expectancy of wolves compared to red foxes and the role of wolves as apex predators compared to red foxes as meso-carnivores. The results obtained confirm the important role that these wild canids play in the circulation of the parasite.

OBJECTIVE: The cestode Echinococcus granulosus causes cystic echinococcosis, a zoonotic parasitic infection that constitutes a significant public health risk. This parasite has been documented to have potential reservoirs and carriers among wild canids, namely wolves, foxes and jackals. This study aimed to determine the prevalence and molecular characteristics of E. granulosus sensu lato species/genotypes among wild canids in three northern, northeastern and north-western Iran regions.
METHODS: From 2019 to 2022, 93 wild canid carcasses (69 jackals), (22 foxes) and (2 wolves) were collected that were killed in car accidents or illnesses. Analyses of morphology and morphometry were performed to verify the presence of E. granulosus. To determine E. granulosus s.l. species/genotypes, polymerase chain reaction (PCR)-RFLP (ITS1) was performed utilizing the Bsh1236I (BstUI) restriction enzyme. COX1, NADH1 and ITS1 gene sequencing were also performed to confirm the PCR-RFLP results.
RESULTS: During this study, 93 wild canids were examined, and 3.2% (95% CI: 0%-7%) of the 93 were infected with Echinococcus. The north-western region of Iran showed two out of 30 jackals (6.6%) infected with adult Echinococcus compared to one out of 35 jackals (2.8%) in the northern region. DNA from Echinococcus was detected in these individuals by PCR. Based on PCR-RFLP analysis of the ITS1 gene and sequencing of COX1, NADH1 and ITS1 gene, E. granulosus sensu stricto genotype was confirmed in the jackals that had been infected.
CONCLUSIONS: Evidence shows that E. granulosus occurs in jackals in Iran, with the E. granulosus s.s. genotype being the most common. This parasite has been identified as a zoonotic parasite with a genotype that can be transmitted to livestock and humans. Establishing effective control measures to prevent the spread of echinococcosis and ensure public health is crucial.

Domestication has long been considered the most powerful evolutionary engine behind dramatic reductions in brain size in several taxa, and the dog (Canis familiaris) is considered as a typical example that shows a substantial decrease in brain size relative to its ancestor, the grey wolf (Canis lupus). However, to make the case for exceptional evolution of reduced brain size under domestication requires an interspecific approach in a phylogenetic context that can quantify the extent by which domestication reduces brain size in comparison to closely related non-domesticated species responding to different selection factors in the wild. Here, we used a phylogenetic method to identify evolutionary singularities to test if the domesticated dog stands out in terms of relative brain size from other species of canids. We found that the dog does not present unambiguous signature of evolutionary singularity with regard to its small brain size, as the results were sensitive to the considerations about the ancestral trait values upon domestication. However, we obtained strong evidence for the hibernating common raccoon dog (Nyctereutes procyonoides) being an evolutionary outlier for its brain size. Therefore, domestication is not necessarily an exceptional case concerning evolutionary reductions in brain size in an interspecific perspective.

Blood samples from fifteen captive Indian wolves (Canis lupus pallipes) maintained at Arignar Anna Zoological Park, Vandalur, Chennai were screened for the presence of Babesia spp., Ehrlichia canis and Trypnosoma evansi DNA by PCR. Out of 15 wolf samples, 3 samples were found positive for Babesia spp. The amplified 18S rRNA gene fragments from 3 wolves were sequenced and confirmed as Babesia gibsoni. A maximum likelihood tree was constructed using the three sequences along with other Babesia spp. sequences derived from GenBank adopting HKY nucleotide substitution model based on the Bayesian Information Criterion. The phylogenetic analysis confirmed that the three sequences were of Babesia gibsoni and highly divergent from Babesia canis, B. vogeli and B. vulpes. This might be a possible spill over event of B. gibsoni from community dogs through blood feeding dog ticks. This is the first report and molecular confirmation of B. gibsoni infection in captive Indian wolves.

The mammalian vomeronasal system enables the perception of chemical signals crucial for social communication via the receptor families V1R and V2R. These receptors are linked with the G-protein subunits, Gαi2 and Gαo, respectively. Exploring the evolutionary pathways of V1Rs and V2Rs across mammalian species remains a significant challenge, particularly when comparing genomic data with emerging immunohistochemical evidence. Recent studies have revealed the expression of Gαo in the vomeronasal neuroepithelium of wild canids, including wolves and foxes, contradicting predictions based on current genomic annotations. Our study provides detailed immunohistochemical evidence, mapping the expression of V2R receptors in the vomeronasal sensory epithelium, focusing particularly on wild canids, specifically wolves and foxes. An additional objective involves contrasting these findings with those from domestic species like dogs to highlight the evolutionary impacts of domestication on sensory systems. The employment of a specific antibody raised against the mouse V2R2, a member of the C-family of vomeronasal receptors, V2Rs, has confirmed the presence of V2R2-immunoreactivity (V2R2-ir) in the fox and wolf, but it has revealed the lack of expression in the dog. This may reflect the impact of domestication on the regression of the VNS in this species, in contrast to their wild counterparts, and it underscores the effects of artificial selection on sensory functions. Thus, these findings suggest a more refined chemical detection capability in wild species.

Dingoes are culturally and ecologically important free-living canids whose ancestors arrived in Australia over 3,000 B.P., likely transported by seafaring people. However, the early history of dingoes in Australia-including the number of founding populations and their routes of introduction-remains uncertain. This uncertainty arises partly from the complex and poorly understood relationship between modern dingoes and New Guinea singing dogs, and suspicions that post-Colonial hybridization has introduced recent domestic dog ancestry into the genomes of many wild dingo populations. In this study, we analyzed genome-wide data from nine ancient dingo specimens ranging in age from 400 to 2,746 y old, predating the introduction of domestic dogs to Australia by European colonists. We uncovered evidence that the continent-wide population structure observed in modern dingo populations had already emerged several thousand years ago. We also detected excess allele sharing between New Guinea singing dogs and ancient dingoes from coastal New South Wales (NSW) compared to ancient dingoes from southern Australia, irrespective of any post-Colonial hybrid ancestry in the genomes of modern individuals. Our results are consistent with several demographic scenarios, including a scenario where the ancestry of dingoes from the east coast of Australia results from at least two waves of migration from source populations with varying affinities to New Guinea singing dogs. We also contribute to the growing body of evidence that modern dingoes derive little genomic ancestry from post-Colonial hybridization with other domestic dog lineages, instead descending primarily from ancient canids introduced to Sahul thousands of years ago.

Scent rolling, a behaviour observed in various large carnivores like wolves, entails the animal lowering its chin and neck towards a scent, followed by rubbing the head, neck, shoulders, and back into it. This behaviour is prevalent among wolves exposed to diverse scents, though its exact purpose remains uncertain. In this study, captive wolves at Osijek Zoo responded differently to odours during olfactory enrichment sessions. In the initial year of this study, the highest level of interest, evidenced by both the frequency of responses and scent-rolling behaviour, was noted when the wolves encountered odours such as curry and rosemary, along with deer/mouflon and rat faeces. While certain odours, such as llama faeces and deer/mouflon faeces, garnered longer durations of interest in the second year of study, others, like guinea pig faeces and oregano, elicited shorter responses. Female wolves demonstrated a higher level of engagement with scents compared with males, particularly through scent rolling behaviour, which was exclusively observed in females during the second year of this study. Interestingly, certain odours did not trigger scent rolling, suggesting selective preferences. On the other hand, sheep\'s wool induced the longest duration of scent rolling, and a lack of significant differences in behaviour was observed between morning and afternoon sessions. Despite the existence of multiple hypotheses put forward to explain the causation of scent rolling in wolves, it seems to be elicited by unfamiliar odours.