A worldwide perspective on large carnivore attacks on humans.

Large carnivores have long fascinated human societies and have profound influences on ecosystems. However, their conservation represents one of the greatest challenges of our time, particularly where attacks on humans occur. Where human recreational and/or livelihood activities overlap with large carnivore ranges, conflicts can become particularly serious. Two different scenarios are responsible for such overlap: In some regions of the world, increasing human populations lead to extended encroachment into large carnivore ranges, which are subject to increasing contraction, fragmentation, and degradation. In other regions, human and large carnivore populations are expanding, thus exacerbating conflicts, especially in those areas where these species were extirpated and are now returning. We thus face the problem of learning how to live with species that can pose serious threats to humans. We collected a total of 5,440 large carnivore (Felidae, Canidae, and Ursidae; 12 species) attacks worldwide between 1950 and 2019. The number of reported attacks increased over time, especially in lower-income countries. Most attacks (68%) resulted in human injuries, whereas 32% were fatal. Although attack scenarios varied greatly within and among species, as well as in different areas of the world, factors triggering large carnivore attacks on humans largely depend on the socioeconomic context, with people being at risk mainly during recreational activities in high-income countries and during livelihood activities in low-income countries. The specific combination of local socioeconomic and ecological factors is thus a risky mix triggering large carnivore attacks on humans, whose circumstances and frequencies cannot only be ascribed to the animal species. This also implies that effective measures to reduce large carnivore attacks must also consider the diverse local ecological and social contexts.

Long-term, climate-driven phenological shift in a tropical large carnivore.

Understanding the degree to which animals are shifting their phenology to track optimal conditions as the climate changes is essential to predicting ecological responses to global change. Species at low latitudes or high trophic levels are theoretically expected to exhibit weaker phenological responses than other species, but limited research on tropical systems or on top predators impedes insight into the contexts in which these predictions are upheld. Moreover, a lack of phenological studies on top predators limits understanding of how climate change impacts propagate through entire ecosystems. Using a 30-y dataset on endangered African wild dogs (Lycaon pictus), we examined changes in reproductive phenology and temperatures during birthing and denning over time, as well as potential fitness consequences of these changes. We hypothesized that their phenology would shift to track a stable thermal range over time. Data from 60 packs and 141 unique pack-years revealed that wild dogs have delayed parturition by 7 days per decade on average in response to long-term warming. This shift has led to temperatures on birthing dates remaining relatively stable but, contrary to expectation, has led to increased temperatures during denning periods. Increased denning temperatures were associated with reduced reproductive success, suggesting that a continued phenological shift in the species may become maladaptive. Such results indicate that climate-driven shifts could be more widespread in upper trophic levels than previously appreciated, and they extend theoretical understanding of the species traits and environmental contexts in which large phenological shifts can be expected to occur as the climate changes.

Comparative genomics uncovers the evolutionary history, demography, and molecular adaptations of South American canids.

The remarkable radiation of South American (SA) canids produced 10 extant species distributed across diverse habitats, including disparate forms such as the short-legged, hypercarnivorous bush dog and the long-legged, largely frugivorous maned wolf. Despite considerable research spanning nearly two centuries, many aspects of their evolutionary history remain unknown. Here, we analyzed 31 whole genomes encompassing all extant SA canid species to assess phylogenetic relationships, interspecific hybridization, historical demography, current genetic diversity, and the molecular bases of adaptations in the bush dog and maned wolf. We found that SA canids originated from a single ancestor that colonized South America 3.9 to 3.5 Mya, followed by diversification east of the Andes and then a single colonization event and radiation of Lycalopex species west of the Andes. We detected extensive historical gene flow between recently diverged lineages and observed distinct patterns of genomic diversity and demographic history in SA canids, likely induced by past climatic cycles compounded by human-induced population declines. Genome-wide scans of selection showed that disparate limb proportions in the bush dog and maned wolf may derive from mutations in genes regulating chondrocyte proliferation and enlargement. Further, frugivory in the maned wolf may have been enabled by variants in genes associated with energy intake from short-chain fatty acids. In contrast, unique genetic variants detected in the bush dog may underlie interdigital webbing and dental adaptations for hypercarnivory. Our analyses shed light on the evolution of a unique carnivoran radiation and how it was shaped by South American topography and climate change.

Tracing Eastern Wolf Origins From Whole-Genome Data in Context of Extensive Hybridization.

Southeastern Canada is inhabited by an amalgam of hybridizing wolf-like canids, raising fundamental questions regarding their taxonomy, origins, and timing of hybridization events. Eastern wolves (Canis lycaon), specifically, have been the subject of significant controversy, being viewed as either a distinct taxonomic entity of conservation concern or a recent hybrid of coyotes (C. latrans) and grey wolves (C. lupus). Mitochondrial DNA analyses show some evidence of eastern wolves being North American evolved canids. In contrast, nuclear genome studies indicate eastern wolves are best described as a hybrid entity, but with unclear timing of hybridization events. To test hypotheses related to these competing findings we sequenced whole genomes of 25 individuals, representative of extant Canadian wolf-like canid types of known origin and levels of contemporary hybridization. Here we present data describing eastern wolves as a distinct taxonomic entity that evolved separately from grey wolves for the past ∼67,000 years with an admixture event with coyotes ∼37,000 years ago. We show that Great Lakes wolves originated as a product of admixture between grey wolves and eastern wolves after the last glaciation (∼8,000 years ago) while eastern coyotes originated as a product of admixture between "western" coyotes and eastern wolves during the last century. Eastern wolf nuclear genomes appear shaped by historical and contemporary gene flow with grey wolves and coyotes, yet evolutionary uniqueness remains among eastern wolves currently inhabiting a restricted range in southeastern Canada.

Long-term Small Population Size, Deleterious Variation, and Altitude Adaptation in the Ethiopian Wolf, a Severely Endangered Canid.

Ethiopian wolves, a canid species endemic to the Ethiopian Highlands, have been steadily declining in numbers for decades. Currently, out of 35 extant species, it is now one of the world's most endangered canids. Most conservation efforts have focused on preventing disease, monitoring movements and behavior, and assessing the geographic ranges of sub-populations. Here, we add an essential layer by determining the Ethiopian wolf's demographic and evolutionary history using high-coverage (∼40×) whole-genome sequencing from 10 Ethiopian wolves from the Bale Mountains. We observe exceptionally low diversity and enrichment of weakly deleterious variants in the Ethiopian wolves in comparison with two North American gray wolf populations and four dog breeds. These patterns are consequences of long-term small population size, rather than recent inbreeding. We infer the demographic history of the Ethiopian wolf and find it to be concordant with historic records and previous genetic analyses, suggesting Ethiopian wolves experienced a series of both ancient and recent bottlenecks, resulting in a census population size of fewer than 500 individuals and an estimated effective population size of approximately 100 individuals. Additionally, long-term small population size may have limited the accumulation of strongly deleterious recessive mutations. Finally, as the Ethiopian wolves have inhabited high-altitude areas for thousands of years, we searched for evidence of high-altitude adaptation, finding evidence of positive selection at a transcription factor in a hypoxia-response pathway [CREB-binding protein (CREBBP)]. Our findings are pertinent to continuing conservation efforts and understanding how demography influences the persistence of deleterious variation in small populations.

Running, jumping, hunting, and scavenging: Functional analysis of vertebral mobility and backbone properties in carnivorans.

Carnivorans are well-known for their exceptional backbone mobility, which enables them to excel in fast running and long jumping, leading to them being among the most successful predators amongst terrestrial mammals. This study presents the first large-scale analysis of mobility throughout the presacral region of the vertebral column in carnivorans. The study covers representatives of 6 families, 24 genera and 34 species. We utilized a previously developed osteometry-based method to calculate available range of motion, quantifying all three directions of intervertebral mobility: sagittal bending (SB), lateral bending (LB), and axial rotation (AR). We observed a strong phylogenetic signal in the structural basis of the vertebral column (vertebral and joint formulae, length proportions of the backbone modules) and an insignificant phylogenetic signal in most characteristics of intervertebral mobility. This indicates that within the existing structure (stabilization of which occurred rather early in different phylogenetic lineages), intervertebral mobility in carnivorans is quite flexible. Our findings reveal that hyenas and canids, which use their jaws to seize prey, are characterized by a noticeably elongated cervical region and significantly higher SB and LB mobility of the cervical joints compared to other carnivorans. In representatives of other carnivoran families, the cervical region is very short, but the flexibility of the neck (both SB and LB) is significantly higher than that of short-necked odd-toed and even-toed ungulates. The lumbar region of the backbone in carnivorans is dorsomobile in the sagittal plane, being on average ~23° more mobile than in artiodactyls and ~38° more mobile than in perissodactyls. However, despite the general dorsomobility, only some representatives of Canidae, Felidae, and Viverridae are superior in lumbar flexibility to the most dorsomobile ungulates. The most dorsomobile artiodactyls are equal or even superior to carnivorans in their ability to engage in dorsal extension during galloping. In contrast, carnivorans are far superior to ungulates in their ability to engage ventral flexion. The cumulative SB in the lumbar region in carnivorans largely depends on the mode of running and hunting. Thus, adaptation to prolonged and enduring pursuit of prey in hyenas is accompanied by markedly reduced SB flexibility in the lumbar region. A more dorsostable run is also a characteristic of the Ursidae, and the peculiar maned wolf. Representatives of Felidae and Canidae have significantly more available SB mobility in the lumbar region. However, they fully engage it only occasionally at key moments of the hunt associated with the direct capture of the prey or when running in a straight line at maximum speed.

Dispersal and connectivity in increasingly extreme climatic conditions.

While climate change has been shown to impact several life-history traits of wild-living animal populations, little is known about its effects on dispersal and connectivity. Here, we capitalize on the highly variable flooding regime of the Okavango Delta to investigate the impacts of changing environmental conditions on the dispersal and connectivity of the endangered African wild dog (Lycaon pictus). Based on remote sensed flood extents observed over 20 years, we derive two extreme flood scenarios: a minimum and a maximum flood extent, representative of very dry and very wet environmental periods. These conditions are akin to those anticipated under increased climatic variability, as it is expected under climate change. Using a movement model parameterized with GPS data from dispersing individuals, we simulate 12,000 individual dispersal trajectories across the ecosystem under both scenarios and investigate patterns of connectivity. Across the entire ecosystem, surface water coverage during maximum flood extent reduces dispersal success (i.e., the propensity of individuals to disperse between adjacent subpopulations) by 12% and increases dispersal durations by 17%. Locally, however, dispersal success diminishes by as much as 78%. Depending on the flood extent, alternative dispersal corridors emerge, some of which in the immediate vicinity of human-dominated landscapes. Notably, under maximum flood extent, the number of dispersing trajectories moving into human-dominated landscapes decreases by 41% at the Okavango Delta's inflow, but increases by 126% at the Delta's distal end. This may drive the amplification of human-wildlife conflict. While predicting the impacts of climate change on environmental conditions on the ground remains challenging, our results highlight that environmental change may have significant consequences for dispersal patterns and connectivity, and ultimately, population viability. Acknowledging and anticipating such impacts will be key to effective conservation strategies and to preserve vital dispersal corridors in light of climate change and other human-related landscape alterations.

An integrated population model reveals source-sink dynamics for competitively subordinate African wild dogs linked to anthropogenic prey depletion.

Many African large carnivore populations are declining due to decline of the herbivore populations on which they depend. The densities of apex carnivores like the lion and spotted hyena correlate strongly with prey density, but competitively subordinate carnivores like the African wild dog benefit from competitive release when the density of apex carnivores is low, so the expected effect of a simultaneous decrease in resources and dominant competitors is not obvious. Wild dogs in Zambia's South Luangwa Valley Ecosystem occupy four ecologically similar areas with well-described differences in the densities of prey and dominant competitors due to spatial variation in illegal offtake. We used long-term monitoring data to fit a Bayesian integrated population model (IPM) of the demography and dynamics of wild dogs in these four regions. The IPM used Leslie projection to link a Cormack-Jolly-Seber model of area-specific survival (allowing for individual heterogeneity in detection), a zero-inflated Poisson model of area-specific fecundity and a state-space model of population size that used estimates from a closed mark-capture model as the counts from which (latent) population size was estimated. The IPM showed that both survival and reproduction were lowest in the region with the lowest density of preferred prey (puku, Kobus vardonii and impala, Aepyceros melampus), despite little use of this area by lions. Survival and reproduction were highest in the region with the highest prey density and intermediate in the two regions with intermediate prey density. The population growth rate ( λ ) was positive for the population as a whole, strongly positive in the region with the highest prey density and strongly negative in the region with the lowest prey density. It has long been thought that the benefits of competitive release protect African wild dogs from the costs of low prey density. Our results show that the costs of prey depletion overwhelm the benefits of competitive release and cause local population decline where anthropogenic prey depletion is strong. Because competition is important in many guilds and humans are affecting resources of many types, it is likely that similarly fundamental shifts in population limitation are arising in many systems.

Why do dogs wag their tails?

Tail wagging is a conspicuous behaviour in domestic dogs (Canis familiaris). Despite how much meaning humans attribute to this display, its quantitative description and evolutionary history are rarely studied. We summarize what is known about the mechanism, ontogeny, function and evolution of this behaviour. We suggest two hypotheses to explain its increased occurrence and frequency in dogs compared to other canids. During the domestication process, enhanced rhythmic tail wagging behaviour could have (i) arisen as a by-product of selection for other traits, such as docility and tameness, or (ii) been directly selected by humans, due to our proclivity for rhythmic stimuli. We invite testing of these hypotheses through neurobiological and ethological experiments, which will shed light on one of the most readily observed yet understudied animal behaviours. Targeted tail wagging research can be a window into both canine ethology and the evolutionary history of characteristic human traits, such as our ability to perceive and produce rhythmic behaviours.

The reduction in relative brain size in the domesticated dog is not an evolutionary singularity among the canids.

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.

Detection and complete genome characterization of a genogroup X (GX) sapovirus (family Caliciviridae) from a golden jackal (Canis aureus) in Hungary.

In this study, a novel genotype of genogroup X (GX) sapovirus (family Caliciviridae) was detected in the small intestinal contents of a golden jackal (Canis aureus) in Hungary and characterised by viral metagenomics and next-generation sequencing techniques. The complete genome of the detected strain, GX/Dömsöd/DOCA-11/2020/HUN (PP105600), is 7,128 nt in length. The ORF1- and ORF2-encoded viral proteins (NSP, VP1, and VP2) have 98%, 95%, and 88% amino acid sequence identity to the corresponding proteins of genogroup GX sapoviruses from domestic pigs, but the nucleic acid sequence identity values for their genes are significantly lower (83%, 77%, and 68%). During an RT-PCR-based epidemiological investigation of additional jackal and swine samples, no other GX strains were detected, but a GXI sapovirus strain, GXI/Tótfalu/WBTF-10/2012/HUN (PP105601), was identified in a faecal sample from a wild boar (Sus scrofa). We report the detection of members of two likely underdiagnosed groups of sapoviruses (GX and GXI) in a golden jackal and, serendipitously, in a wild boar in Europe.

Phylogeographic analyses of an endemic Neotropical fox (Lycalopex vetulus) reveal evidence of hybridization with a different canid species (L. gymnocercus).

The hoary fox (Lycalopex vetulus) is the only species of the Canidae (Mammalia: Carnivora) endemic to Brazil, and so far has been the target of few genetic studies. Using microsatellites and mtDNA markers, we investigated its present genetic diversity and population structure. We also tested the hypothesis that this species currently hybridizes with the pampas fox (L. gymnocercus), as suggested by previous mtDNA data from two individuals. We collected tissue and blood samples from animals representing most of the two species' distributions in Brazil (n = 87), including their recently discovered geographic contact zone in São Paulo state. We observed that the hoary fox exhibits high levels of genetic diversity and low levels of population structure. We identified six individuals from São Paulo state with clear evidence of hybridization based on introgressed pampas fox mitochondrial DNA and/or admixed microsatellite genotypes (three individuals bore both types of evidence). These results demonstrate the existence of admixed individuals between hoary and pampas foxes in southeastern Brazil, representing the first identified case of interspecies admixture between native South American canids. We discuss our findings in the context of the evolutionary history of these foxes and address potential conservation implications of this interspecies hybridization process.

The value of hybrid genomes: Building two highly contiguous reference genome assemblies to advance Canis genomic studies.

Previous studies of canid population and evolutionary genetics have relied on high-quality domestic dog reference genomes that have been produced primarily for biomedical and trait mapping studies in dog breeds. However, the absence of highly contiguous genomes from other Canis species like the gray wolf and coyote, that represent additional distinct demographic histories, may bias inferences regarding interspecific genetic diversity and phylogenetic relationships. Here, we present single haplotype de novo genome assemblies for the gray wolf and coyote, generated by applying the trio-binning approach to long sequence reads generated from the genome of a female first-generation hybrid produced from a gray wolf and coyote mating. The assemblies were highly contiguous, with contig N50 sizes of 44.6 and 42.0 Mb for the wolf and coyote, respectively. Genome scaffolding and alignments between the two Canis assemblies and published dog reference genomes showed near complete collinearity, with one exception: a coyote-specific chromosome fission of chromosome 13 and fusion of the proximal portion of that chromosome with chromosome 8, retaining the Canis-typical haploid chromosome number of 2n = 78. We evaluated mapping quality for previous RADseq data from 334 canids and found nearly identical mapping quality and patterns among canid species and regional populations regardless of the genome used for alignment (dog, coyote, or gray wolf). These novel wolf and coyote genome reference assemblies will be important resources for proper and accurate inference of Canis demography, taxonomic evaluation, and conservation genetics.

Phylogenetic inferences based on distinct molecular markers reveals a novel Babesia (Babesia pantanalensis nov. sp.) and a Hepatozoon americanum-related genotype in crab-eating foxes (Cerdocyon thous).

Piroplasmids and Hepatozoon spp. Are apicomplexan protozoa that may cause disease in several canid species. The present study aimed to expand the knowledge on the diversity of piroplasmids and Hepatozoon in crab-eating foxes (Cerdocyon thous; n = 12) sampled in the Pantanal of Mato Grosso do Sul State, central-western Brazil. PCR assays based on the 18S rRNA were used as screening. Three (25%) and 11 (91.7%) were positive for piroplasmids and Hepatozoon spp., respectively. Co-infection was found in three C. thous. Phylogenetic analyses based on the near-complete 18S rRNA, cox-1 and hsp70 genes evidenced the occurrence of a novel of Babesia spp. (namely Babesia pantanalensis nov. sp.) closely related to Rangelia vitalii and Babesia sp. 'Coco'. This finding was supported by the genetic divergence analysis which showed (i) high divergence, ranging from 4.17 to 5.62% for 18 S rRNA, 6.16% for hps70 and 4.91-9.25% for cox-1 and (ii) the genotype network (which displayed sequences separated from the previously described Piroplasmida species by median vectors and several mutational events). Also, phylogenetic analysis based on the 18S rRNA gene of Hepatozoon spp. positioned the sequences obtained herein in a clade phylogenetically related to Hepatozoon sp. 'Curupira 2', Hepatozoon sp. detected in domestic and wild canids from Uruguay and Hepatozoon americanum. The present study described Babesia pantanalensis nov sp. and Hepatozoon closely related to H. americanum in crab-eating foxes from Brazil. Moreover, the coinfection by piroplasmids and Hepatozoon sp. for the first time in crab-eating foxes strongly suggesting that this wild canid species potentially acts as a bio-accumulate of hemoprotozoan in wild environment.

A cross-sectional study to quantify the prevalence of Toxocara canis in dogs in the Central Highlands of Vietnam.

Toxocara canis is a globally distributed zoonotic parasite. The parasite has recently become a concern for public health in Vietnam. This cross-sectional study aimed to identify and quantify the risk factors associated with T. canis infection in dogs in Dak Lak province in the Central Highlands of Vietnam. The risk factors were identified using a mixed-effects logistic regression model and quantified using population attributable fractions. Examination of fecal samples collected from 1455 dogs using the sodium nitrate flotation technique showed 37.32% (95% CI: 34.83-39.86) of dogs infected with T. canis. The factors, including study location, multiple dogs living in a household, dog age, dog breed, and places keeping dogs were associated with a dog's likelihood of being T. canis infection. The household and individual dog levels contributed 17% and 82%, respectively, to the prevalence of T. canis in dogs. The adjusted population attributable fraction for confining dogs and raising an individual dog per household was 52% and 27%, respectively. The result of this study indicated that to minimize the burden of T. canis, intervention measures should target individual dogs and household levels.

New insights on the phylogeography of Hepatozoon canis in Brazil.

This study aimed to molecularly characterize the Hepatozoon spp. infecting domestic and wild dogs in Brazil. A total of 22 whole blood samples tested positive for Hepatozoon spp., and five samples were sequenced for the 18S rDNA gene from H. canis after PCR amplification with four primer sets. Phylogenetic analysis using Bayesian inference showed that the three H. canis isolates from domestic dogs were not monophyletic; however, they were more closely related to each other than to other H. canis sequences. The isolate from the hoary fox (Lycalopex vetulus) was phylogenetically more distant. Two haplotype networks were constructed, identifying 10 haplotypes of H. canis in Brazil, with H10 constituting the largest group. It contains nine isolates, including three from domestic dogs. The H5 haplotype grouped the sequence of L. vetulus with two additional sequences from hosts Tapirus terrestris and L. vetulus, representing the sole haplotype with wild hosts. Bayesian analysis suggested the possible existence of two genetic groups of H. canis in Brazil, indicating gene flow of this agent within the country. These findings contribute valuable insights for a more comprehensive understanding of the molecular diversity of Hepatozoon spp. in Brazil and may help in the development of effective control measures.

First Immunohistochemical Demonstration of the Expression of a Type-2 Vomeronasal Receptor, V2R2, in Wild Canids.

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.

A RETROSPECTIVE STUDY OF DISEASE PROCESSES IN MANED WOLVES (CHRYSOCYON BRACHYURUS) IN NORTH AMERICAN ZOOLOGICAL INSTITUTIONS WITH EMPHASIS ON UROLITHIASIS, INFLAMMATORY BOWEL DISEASE, AND NEOPLASIA.

The objective of this retrospective study is to summarize causes of disease and mortality in maned wolves (Chrysocyon brachyurus) in the North American Species Survival Plan Program (SSP) population. This information will inform and enhance animal health, husbandry, and conservation efforts. Pathology reports were requested from all zoological institutions housing maned wolves between 1930 and 2021. Data were reviewed and cause of death (COD) and reported diseases were summarized and compared by age group, organ system and disease process. One hundred and seventy-one wolves, 82 females and 89 males, met the inclusion criteria. The majority were geriatric (>11 yr; n = 96) or adult (2-11 yr; n = 67). Noninfectious diseases were the most common COD by process (n = 94; 54.9%). For COD by organ system, diseases of the digestive (n = 41) and urinary (n = 34) systems were most common. Neoplasia was the most common noninfectious COD and was the primary COD in 37 wolves (21.6% overall; 39.4% of noninfectious diseases). A total of 145 benign (n = 72) and malignant (n = 73) neoplasms were diagnosed in 44 individuals. Dysgerminoma was the most commonly reported tumor (n = 18), and was the most common neoplastic COD (n = 8). Cystinuria or urolithiasis (n = 71) and gastritis, enteritis, enterocolitis, or colitis (n = 50) (overall and grouped in each system due to presumed common underlying cause) were also common but were more often reported as comorbidities than as COD (n = 16 and n = 11, respectively). Infectious COD were reported in 17 wolves and included babesiosis (n = 4), acanthocephalans (n = 2), and one viral infection. Infections with a variety of bacteria in different organ systems were a COD in eight wolves.

Higher Mortality Is Not a Universal Cost of Dispersal: A Case Study in African Wild Dogs.

AbstractMortality is considered one of the main costs of dispersal. A reliable evaluation of mortality, however, is often hindered by a lack of information about the fate of individuals that disappear under unexplained circumstances (i.e., missing individuals). Here, we addressed this uncertainty by applying a Bayesian mortality analysis that inferred the fate of missing individuals according to information from individuals with known fate. Specifically, we tested the hypothesis that mortality during dispersal is higher than mortality among nondispersers using 32 years of mark-resighting data from a free-ranging population of the endangered African wild dog (Lycaon pictus) in northern Botswana. Contrary to expectations, we found that mortality during dispersal was lower than mortality among nondispersers, indicating that higher mortality is not a universal cost of dispersal. Our findings suggest that group living can incur costs for certain age classes, such as limited access to resources as group density increases, that exceed the mortality costs associated with dispersal. By challenging the accepted expectation of higher mortality during dispersal, we urge for further investigations of this key life history trait and propose a robust statistical approach to reduce bias in mortality estimates.

Increasing ambient temperatures trigger shifts in activity patterns and temporal partitioning in a large carnivore guild.

Shifts in species' interactions are implicated as an important proximate cause underpinning climate-change-related extinction. However, there is little empirical evidence on the pathways through which climate conditions, such as ambient temperature, impact community dynamics. The timing of activities is a widespread behavioural adaptation to environmental variability, and temporal partitioning is a key mechanism that facilitates coexistence, especially within large carnivore communities. We investigated temperature impacts on community dynamics through its influence on the diel activity of, and temporal partitioning amongst, four sympatric species of African large carnivores: lions (Panthera leo), leopards (Panthera pardus), cheetahs (Acinonyx jubatus) and African wild dogs (Lycaon pictus). Activity of all species was shaped by a combination of light availability and temperature, with most species becoming more nocturnal and decreasing activity levels with increasing temperatures. A nocturnal shift was most pronounced in cheetahs, the most diurnal species during median temperatures. This shift increased temporal overlap between cheetahs and other carnivore species by up to 15.92%, highlighting the importance of considering the responses of interacting sympatric species when inferring climate impacts on ecosystems. Our study provides evidence that temperature can significantly affect temporal partitioning within a carnivore guild by generating asymmetrical behavioural responses amongst functionally similar species.