Chrysocyon Research Articles

A continental-wide decline of occupancy and diversity in five Neotropical carnivores

The Neotropics are a global biodiversity hotspot that has undergone dramatic land use changes over the last decades. However, a temporal perspective on the continental-wide distributions of species in this region is still missing. To unveil it, we model the entire area of occupancy of five Neotropical carnivore species at two time periods (2000–2013 and 2014–2021) using integrated species distribution models (ISDMs) in a Bayesian framework. The carnivores are the jaguarundi (Herpailurus yagouaroundi), margay (Leopardus wiedii), maned wolf (Chrysocyon brachyurus), tayra (Eira barbara), and giant otter (Pteronura brasiliensis). We mapped the temporal change, the areas where gains and losses accumulated for all species (hotspots of change) and calculated the temporal species turnover and change in spatial turnover. We show that (1) most carnivore species have declined their area of occupancy (i.e., range size) in the last two decades, (2) their diversity has decreased over time, mostly in the Chaco region, and (3) that hotspots of fast species composition turnover are in Chaco, the Caatinga region, and northwest of Mexico. We discuss how these newly identified hotspots of change overlap with regions of well-known and pronounced land use transformation. These estimated patterns of overall decline are alarming, more so given that four out of the five species had been classified as not threatened by IUCN. The official global threat status of these species may need to be re-evaluated. All this would be invisible if standard forecasts, local expert knowledge, or static threat criteria, such as range size, were used. We thus provide a new approach to evaluate past species range dynamics based on multiple lines of evidence, which can be employed over more species in the future, particularly in under-sampled regions.

Radiographic evaluation of the forelimb bone development in maned wolves (Chrysocyon brachyurus).

This study aimed to assess the fusion of growth plates and the development of secondary ossification centres in the forelimb bones of maned wolves (Chrysocyon brachyurus), contrasting the findings with established data from domestic dogs. Three maned wolves, comprising one male and two females, initially aged between 3 and 4 months, were subjected to monthly radiographic evaluations until 10-11 months of age, followed by bimonthly assessments until 18-19 months of age, encompassing both forelimbs. The closure times of growth plates were observed as follows: supraglenoid tubercle (7-8 months), proximal humerus (17-19 months), distal humerus (8-9 months), medial epicondyle of the humerus (8-9 months), proximal ulna (9-10 months), proximal radius (13-15 months), distal ulna (13-15 months) and distal radius (17-19 months). Statistical analysis revealed significant differences in the areas of secondary ossification centres in the proximal epiphyses of the humerus and radius, respectively, observed from the initial evaluation at 8-9 months and 6-7 months. Conversely, the epiphyses of the supraglenoid tubercle, distal humerus, proximal ulna, distal ulna, medial epicondyle of the humerus and distal radius did not exhibit significant area differences between 3-4 months and 4-5 months, yet notable distinctions emerged at 5-6 months. In summary, while the radiographic appearance of epiphyseal growth plates and secondary ossification centres in maned wolves resembles that of domestic dogs, closure times vary. These findings contribute to understanding the dynamics of epiphyseal growth plates in this species.

A hyaena on stilts: comparison of the limb morphology of Ictitherium ebu (Mammalia: Hyaenidae) from the Late Miocene of Lothagam, Turkana Basin, Kenya with extant Canidae and Hyaenidae.

The long, gracile morphology of the limb bones of the Late Miocene hyaenid Ictitherium ebu has led to the hypothesis that this animal was cursorial. The forelimb and femur of the holotype were compared with specimens of extant Hyaenidae and Canidae. Two morphometric methods were used. The first used measurements to calculate indices of different morphological characters. The second method involved capturing photographs of the anterior distal humerus of each specimen, mapping six landmarks on them, and calculating truss distances. These distances represent a schematic reproduction of the elbow. Multivariate statistical analysis primarily separated the data based on taxonomy, yet locomotor and habitat categories were also considered. Ictitherium ebu has an overall morphology similar to that of the maned wolf and a distal humerus reminiscent of that of the aardwolf. The long, gracile limb bones of I. ebu are suggested to be adaptations for pouncing on prey, for locomotor efficiency, and for looking over the tall grass of the open environments the animal lived in, much like the present-day maned wolf.

Detection and monitoring of the fauna of medium and large mammals using camera traps in a forest remnant area in the municipality of Água Fria de Goiás, Brazil – A tool for nature conservation

Despite the growing amount of information available, biodiversity is still under threat. Wildlife plays a crucial role in maintaining the ecological balance, and it is of logical and strategic importance to promote the further development of fauna recording and monitoring processes, emphasizing the need to strengthen the relationship between humans and nature. The aim was to record the species of medium and large mammals using camera traps. The study was conducted in the EcoCerrado Reserve in the municipality of Água Fria de Goiás, Brazil, between December 2020 and December 2022, using two camera traps in three different phytophysiognomies. 17 mammal species were recorded in 149 camera trap records, including species in the threatened category, such as Myrmecophaga tridactyla, Tapirus terrestrials, Chrysocyon brachyurus, Lycalopex vetulus, Panthera onca and Alouatta caraya. The mammal fauna observed in the study shows that this ecosystem can support populations of native species even in a modified landscape. This finding strengthens the basis for future initiatives aimed at environmental education, ecotourism, and more comprehensive legal protection for this region and other remnants of native vegetation in the Cerrado.

Comparative anatomy of the caudate nucleus in canids and felids: Associations with brain size, curvature, cross-sectional properties, and behavioral ecology.

The evolutionary history of canids and felids is marked by a deep time separation that has uniquely shaped their behavior and phenotype toward refined predatory abilities. The caudate nucleus is a subcortical brain structure associated with both motor control and cognitive, emotional, and executive functions. We used a combination of three-dimensional imaging, allometric scaling, and structural analyses to compare the size and shape characteristics of the caudate nucleus. The sample consisted of MRI scan data obtained from six canid species (Canis lupus lupus, Canis latrans, Chrysocyon brachyurus, Lycaon pictus, Vulpes vulpes, Vulpes zerda), two canid subspecies (Canis lupus familiaris, Canis lupus dingo), as well as three felids (Panthera tigris, Panthera uncia, Felis silvestris catus). Results revealed marked conservation in the scaling and shape attributes of the caudate nucleus across species, with only slight deviations. We hypothesize that observed differences in caudate nucleus size and structure for the domestic canids are reflective of enhanced cognitive and emotional pathways that possibly emerged during domestication.

Spatial distribution of environmental suitability for the maned wolf in central Argentina

Spatial distribution of environmental suitability for the maned wolf in central Argentina

Camera-traps detect the maned wolf preying on broad-snouted caiman eggs

The maned wolf (Chrysocyon brachyurus) is a South-American canid of which conservation guidelines have been implemented due to its population vulnerability. Its trophic ecology demonstrates an omnivorous and opportunistic diet, and even flexibility in response to anthropogenic disturbances. Among the food items identified, the consumption of reptiles is scarce, and includes snakes and lizards. We monitored broad-snouted caiman (Caiman latirostris) nests during four nesting seasons through camera trapping, in savannas and grasslands areas, and recorded maned wolves feeding on caiman eggs during periods of drought. The consumption of an uncommon item, even at low frequency, suggests that camera trapping could become a complementary tool for studying the dietary habits of the maned wolf. Caimans have been a priority for conservation, while maned wolves are currently being released and reintroduced in order to reverse their vulnerable population status. This trophic interaction must be monitored in the long term, to project integral conservation strategies that include both emblematic species.

New records of Maned Wolf, Chrysocyon brachyurus (Illiger, 1815), in Rio Grande do Sul, Brazil: consequences for conservation

We document records of Chrysocyon brachyurus (Illiger, 1815), Maned Wolf, from on a private farm in the municipality of Cambará do Sul, Rio Grande do Sul, Brazil. The farm borders Parque Nacional da Serra Geral, near Fortaleza Canyon. Twelve new records of Maned Wolf were captured with camera traps between 16 March 2023 and 10 November 2023, in five locations. These records are of significance due to the rarity of this species in Rio Grande do Sul.

Epidemiological survey of infectious agents in free-ranging maned wolves (Chrysocyon brachyurus) in Northeastern Brazil.

Infectious diseases are one of the most concerning threats to maned wolves (Chrysocyon brachyurus) due to the potential impact on free-ranging populations. The species is currently classified as vulnerable according to the national list of threatened species and occurs mainly in open habitats, such as the Cerrado, a tropical savannah, which comprises its main distribution area in Brazil. In the northeastern region, it occurs in the Cerrado of Bahia, Piauí, Maranhão, and Tocantins states. Therefore, this study aimed to investigate the occurrence of infectious agents in Chrysocyon brachyurus through an epidemiological assessment of free-ranging individuals in western Bahia, specifically in the Barreiras microregion, a Cerrado area intensely fragmented and anthropized by agricultural activity. Eleven specimens were evaluated for serological titration, antigen research, and genetic material research for canine distemper virus (CDV), canine parvovirus (CPV), adenovirus-canine-type 1 (CAdV-1), canine coronavirus (CCoV), Leptospira interrogans and Toxoplasma gondii from 2020 to 2022. In addition to maned wolves, domestic dogs were also evaluated and tested. All maned wolves (100%) evaluated by the dot-ELISA technique exhibited immunoglobulin M (IgM) and seven (64%) exhibited immunoglobulin G (IgG) against CDV and CPV, while 100% exhibited IgG against CDV when using the immunochromatographic technique. Regarding CAdV-1, 90% were seropositive for IgG, while 64% exhibited IgG against T. gondii. Nine dogs from the region were also sampled, and all (100%) exhibited IgM and IgG against CDV and CPV. For IgG against T. gondii and against CAdV-1, 90% of the animals were seropositive. Molecular evaluation yielded negative results for all maned wolves and dogs assessed for CAdV-1, CDV, and T. gondii, as well as the CCoV antigen. These data indicate the occurrence of viral agents and Toxoplasma gondii in maned wolves and dogs, suggesting circulation in both populations.

Two new records of the maned wolf (Chrysocyon brachyurus (Carnivora: Canidae)) from the semiarid of Bahia, Brazil

The Chrysocyon brachyurus, Maned wolf, is the largest canid in South America, occurring in areas with open formations such as the Pampa, Chaco and, mainly, the Cerrado. Here, we present two new records of the species in the semiarid region of Bahia State, Brazil. One individual was recorded by camera trap in the municipality of Igaporã (Cerrado domain) and another by an amateur cameraman in the municipality of Caetité (Caatinga domain). Our records expand the known distribution of the species and show that it can occur in areas more related to the semiarid.

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.

Carcinoma mamário simples túbulo-papilar metastático Grau II em lobo-guará fêmea (Chrysocyon brachyurus) de vida livre

ABSTRACT: This study described the pathological aspects of a metastatic grade II simple tubulopapillary mammary carcinoma in a free-living senile female maned wolf (Chrysocyon brachyurus). The diagnosis was based on histopathological findings of malignant epithelial cells arranged in tubular and papillary patterns, with marked anisocytosis and anisokaryosis and metastases to regional lymph nodes, lungs, parietal pleura, and pericardium. Also associated to positive immunolabeling of neoplastic cells for Cytokeratin AE1/AE3 and negative for P63, Calponin and Cox-2, added to the cell proliferation index of 26.8%. The findings demonstrated that free-ranging wild canids develop mammary neoplasms similar to those observed in domestic canids.

The last and endangered maned wolves (Chrysocyon brachyurus) from southern Brazil and Uruguay: new records and spatial distribution modeling

ABSTRACTThe biggest canid in the neotropics, the maned wolf (Chrysocyon brachyurus), is endangered in many parts of its distribution. Only eight records have been reported for Uruguay and the southern border of Brazil over the last 30 years. After a multi-year effort, we present nine new records for this area and characterize Uruguay and southern Brazil’s habitat suitability. Our records confirm the current presence of the species in Uruguay, the Brazilian Pampa, and the Atlantic highlands of southern Brazil, although no local population could be identified. Individuals appear to move in an erratic pattern, possibly when searching for other members of the species. Only three regions presented multiple records (all in the Atlantic highlands), indicating the possible existence of local populations. Although most of southern Brazil and Uruguay are highly suitable for the species, none of the 21 surveyed areas (with 50,816 camera trap nights) within putative distribution areas have confirmed the species occurrence, as all records reported here came from opportunistic encounters. In light of this, we believe that very few individuals still occur in the southern limit of the maned wolf distribution, and thus, the species can certainly be classified as critically endangered in the Brazilian Pampa/Uruguayan Savanna.

Serological Survey for Three Canine Viruses in Brazilian Wild Carnivores : Antibodies Against Canine Viruses in Wild Carnivores.

We evaluated the presence of antibodies against CaHV-1, CDV, and CPV-2 in serum samples from Brazilian wild carnivore species. Nine maned wolves and six crab-eating foxes were tested for CaHV-1 and CDV by virus neutralization test and CPV-2 by hemagglutination inhibition assay. Antibodies to CaHV-1, CDV, and CPV-2 were detected in serum samples of 1 (6.7%), 5 (33.3%), and 10 (66.7%) wild carnivores, respectively. Two maned wolves and one crab-eating fox were seropositive simultaneously for CDV and CPV-2. Antibodies against all viruses were detected in one crab-eating fox. This is the first report of CaHV-1 antibody detection in crab-eating foxes.

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.

ANTIMICROBIAL SUSCEPTIBILITY OF STAPHYLOCOCCUS SPP. ISOLATED FROM FELIDS AND CANIDS IN BELO HORIZONTE ZOO, BRAZIL.

The epidemiology of Staphylococcus spp. has become a major concern among humans and animals due to increasing antimicrobial resistance and frequent reports of infection. Despite the importance of animals as reservoirs for staphylococci, little is known about the epidemiology of Staphylococcus spp. in most nondomestic species, including canids and felids. This study evaluated the frequency, distribution, and patterns of antimicrobial resistance of staphylococcal species isolated from captive felids and canids from Belo Horizonte Zoo, Brazil. Rectal, oral, and nasal swabs from apparently healthy maned wolves (Chrysocyon brachyurus, n= 7), a lion (Panthera leo, n = 1), jaguars (Panthera onca, n = 3), and one swab of a cougar (Puma concolor) with an ear infection were streaked onto mannitol salt agar. Colonies identified by matrix-assisted laser desorption/ionization-time of flight mass spectrometry, polymerase chain reaction for the Staphylococcus intermedius group (SIG), and 16S rRNA gene sequencing. Isolates were subjected to antimicrobial susceptibility tests and Staphylococcus pseudintermedius strains were subjected to multilocus sequence typing. Staphylococcus species were isolated from 24 of the 34 samples (70.6%). Among the isolated strains, S. pseudintermedius and Staphylococcus felis were the most frequent species (41.7 and 25%, respectively). Five novel sequence types were identified among the S. pseudintermedius isolates. Resistance to tetracycline (7/24, 29.2%) or penicillin (6/23, 26.1%) was significantly higher than the other antimicrobial agents tested (P < 0.05). One isolate, Staphylococcus nepalensis, was positive for mecA and resistant to five antimicrobials, and was thus classified as multidrug-resistant. The present work suggests that maned wolves are natural hosts of SIG and also reports the isolation of S. felis in sick and healthy, captive, nondomestic carnivores. The isolated staphylococci were susceptible to most classes of antimicrobials tested. However, the multidrug-resistance capability of an S. nepalensis strain reinforces the hypothesis that felids and canids act as reservoirs of pathogens with antimicrobial resistance.

Space use patterns of two large carnivores: Puma (Puma concolor) and Maned Wolf (Chrysocyon brachyurus) in tropical agroecosystems

Abstract Mammalian carnivores are often vulnerable to the conversion of natural habitat. Although some species might be frequent in anthropogenic areas, it is not entirely clear how they use modified landscapes, particularly in tropical agroecosystems. Here, we investigated how Puma (Puma concolor) and Maned Wolf (Chrysocyon brachyurus) used three disturbed areas in southeastern Brazil. We sampled 205 camera stations and estimated species occupancy (Ψ) and detection probabilities (p), interpreted as probability of use and frequency of use, respectively. Our models predicted that both species extensively used the study areas (model-averaged probability of use of 0.65 for pumas and 0.50 for maned wolves). Puma frequency of use was higher in stations further from human structures and areas of savanna. Maned Wolf frequency of use was lower in forest-dominated stations and in a more protected and forested study area. Puma probability of use was high in stations closer to watercourses, while Maned Wolf probability of use was higher in unpaved roads and stations farther from human structures. Our findings suggest that pumas and maned wolves may be able to adapt their use of space in agroecosystems featuring riparian corridors and unpaved roads. Nevertheless, our data also reveal possible impacts to carnivore populations in these systems, such as the degradation of riparian environments, road mortality, and human construction avoidance. Thus, some caution is warranted in considering highly modified environments as safe habitats for large carnivores, until further data on the density and vital rates of these species in agricultural-dominated areas have been quantified.

BEHAVIORAL RESPONSES OF CAPTIVE MANED WOLVES TO OLFACTORY ENRICHMENT

Environmental enrichment (EE) is a technique that increases animal welfare. The behavior of maned wolves when exposed to four odors hidden outside the enclosure was investigated. Using the focal animal method and recording all occurrences, their behavior was analyzed for five minutes in each baseline phase (Basal), during exposure (Exp), and after withdrawal of the stimulus (Pos). Behavioral responses were categorized as positive (P+), negative (N-), and other (Ot). The average P+ increased significantly (P &lt; 0.05) from the Basal to the Exp, but it was not statistically different (P = 0.60) between the Basal and the Pos. Neither N- nor Ot changed statistically in any of the phases (P &gt; 0.5). Maned wolves appeared to be sensitive to this EE with the olfactory stimuli used during the period of olfactory stimulation. The method used is practical, safe, and flexible, and can be useful in sensory enrichment programs.

The Sarcoptic Mange in Maned Wolf (Chrysocyon brachyurus): Mapping an Emerging Disease in the Largest South American Canid.

The maned wolf (Chrysocyon brachyurus) is the largest South American canid. In Brazil, as in other countries, it is considered an endangered species. Habitat loss, landscape changes, hunting, and roadkill are the main threats to this species. In addition, invasive diseases of domestic animals are considered to be an emerging threat to the maned wolf, where parasitic diseases are relevant. Sarcoptic mange is a skin disease caused by the mite Sarcoptes scabiei. This disease is currently almost globally distributed, with a remarkable host diversity. In Brazil, reports of sarcoptic mange in wildlife include several species, both wild and captive. However, the impact of this disease on wildlife is unknown. At the time of writing, there is only one published report of sarcoptic mange in maned wolves. This study sheds light on the occurrence of sarcoptic mange in free-ranging maned wolves in their natural range. A total of 52 cases (suspected and confirmed) of sarcoptic mange were identified through social media review, camera trapping, chemical immobilization and sample collection. These cases were distributed in southeastern Brazil, in the states of São Paulo (n = 34), Minas Gerais (n = 17), and Rio de Janeiro (n = 1), demonstrating a rapid and widespread spread of this disease, although it still only occurs in part of the species' range. We expect that these results will help to subsidize future actions relevant to the control of this emerging disease.

Detection of the maned wolf, a cryptic and vulnerable species, through environmental DNA studies

The maned wolf (Chrysocyon brachyurus) is a vulnerable and ubiquitous species endemic to South America. Their populations are declining due to habitat loss as a consequence of agricultural expansion and exposure to anthropic threats such as road-kills, illegal hunting and diseases. In Argentina, there is a lack of information about its accurate distribution because its populations are sparse and the specimens are very difficult to observe due to its cryptic and lonely behavior, low population density, and type of habitat. In this article, we describe the results of the application of the environmental DNA methodology to carry out indirect monitoring of maned wolf specimens. The data obtained show that this technique is effective in detecting specimens of this mammal, which was verified through direct monitoring. This information represents an adjustment of the methods that can be applied in large-scale monitoring to study the structure and distribution of the maned wolf populations, as well as to obtain genetic data about this species, to design optimal conservation plans to preserve it in Argentina.