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Jaguars and pumas are top-predator species in the Neotropics that are threatened by habitat destruction, illegal poaching of their body parts and their favored prey, and by the human–wildlife conflicts that arise when predators attack livestock. Much of the remaining felid habitat in the Americas is in protected nature reserves that are too small and isolated to support local populations. Surrounding forests therefore play a vital role in felid conservation. Successful long-term conservation of these two felids requires evidence-based knowledge of their biological and ecological requirements. We studied population distributions of jaguars and pumas and their prey in and between two small, private reserves of the Northern Yucatán Peninsula, Mexico, with areas of 25 and 43 km2. During 2 years of camera trapping (2015 and 2016), we detected 21 jaguars, from which we estimated an average space requirement of 28–45 km2/individual. Dietary niche overlap exceeded random expectation. The most frequently occurring prey items in jaguar and puma diets were collared peccary and deer. Jaguar also favored nine-banded armadillos and white-nosed coati, while puma favored canids. Both felids avoided ocellated turkey. Overall, diet of jaguars was less species-rich, but similar in niche breadth, to that of pumas. A fluid use of space by both species, in 2015 tending toward mutual attraction and in 2016 toward partial exclusion of pumas by jaguars, combined with the high dietary overlap, is consistent with a dominance hierarchy facilitating coexistence. Jaguars and pumas favor the same prey as the people in local communities who hunt, which likely will intensify human–wildlife impacts when prey become scarce. We conclude that even small reserves play an important role in increasing the continuity of habitat for prey and large felids, whose generalist habits suppress interspecific competition for increasingly limiting prey that are largely shared between them and humans. [ABSTRACT FROM AUTHOR]

When colonizing new regions, invading species might compete strongly with phylogenetically related species native to the regions they are colonizing, eventually leading to coexistence or displacement. In the southeast of the United States, recently established coyotes (Canis latrans) compete with red fox (Vulpes vulpes) and gray fox (Urocyon cinereoargenteus), although it remains unclear if competition is leading to resource partitioning or displacement by species. Using nitrogen and carbon stable isotopes, we tested the hypothesis that coyotes compete with foxes for food resources, with canids partitioning those resources to mitigate competition. We compared diets of canids in the southeast to those in the Plains region of the United States, a region where all three species historically have coexisted. We analyzed 217 hair samples from both regions pre-1960, prior to coyote colonization of the southeast, and post-2000, after coyotes were ubiquitous there, to assess differences in diet among species for both regions (southeast versus Plains and time periods, pre- versus postcolonization by coyotes). Modeling revealed significant dietary overlap among historical and contemporary populations in the southeast. Historically, all species partitioned resources in the Plains. Contemporarily, red fox and coyotes co-occurring in the Plains overlapped in diet; however, gray fox diet did not overlap with those of red fox and coyotes. Absence of partitioning in diet among co-occurring canids in the southeast indicates that interspecific competition could be strong in the region. Competition among canid populations in the southeast could lead to further resource partitioning among species that promotes coexistence or competitive exclusion of smaller fox species where coyote populations are abundant. [ABSTRACT FROM AUTHOR]

We conducted a geometric morphometric analysis to investigate the morphological variation of the golden wolf, Canis lupaster , and to clarify the morphological and taxonomic affinities of different taxa of the genera Canis and Lupulella. We suggest that the variation observed within the complex of Canis lupaster may be incompatible with what would be expected for a single species. We hypothesize that the nominal form C. l. soudanicus is a synonym of Lupulella adusta rather than being part of the golden wolf complex. The subspecies C. l. bea has a generalized jackal morphology (i.e., clusters together with L. mesomelas and C. aureus) and C. l. lupaster occupies an intermediate morphospace position, between jackal-like forms and wolf-like forms. These results contrast with previously published molecular analysis in which mitochondrial data failed to identify differences among golden wolf populations, and nuclear evidence points to the existence of groups that are incompatible with those recovered by morphological analysis. Regarding other jackals, our results depict the absence of morphological overlap between L. m. mesomelas and L. m. schmidti and no differences between putative subspecies of L. adusta. We call attention to the need for more integrative approaches to solve the taxonomic questions in various African Canidae. [ABSTRACT FROM AUTHOR]

The rise of the Panamanian Isthmus 3–4 million years ago enabled the first dispersal of mammals between North and South America in what is known as the Great American Biotic Interchange. Modern deforestation threatens the historic forest connectivity and creates new habitat for open-country species, as documented by recent expansions of North American coyotes (Canis latrans) and South American crab-eating foxes (Cerdocyon thous) into Central America. We used camera traps to map the expansions of these species into eastern Panama and found that, by 2015, coyote populations had colonized most agricultural area west of Lago Bayano. Most of our camera arrays east of this point documented crab-eating foxes, and evidence from roadkills showed some foxes had advanced farther west, but we never documented both species at the same camera-trap array, suggesting the possibility of fine-scale spatial avoidance. We used a data fusion approach to build species distribution models combining our camera surveys with records from the literature and roadkill. While the auxiliary data improved the predictive accuracy for both species, few clear habitat patterns emerged, which might reflect the generalist tendencies of these canids, or the fact that both are in the early stages of colonizing the region. Camera-trap photos showed that both species were nocturnal and revealed some dog-like morphology in coyotes, which could indicate their recent hybridization with dogs (Canis familiaris). Our continued monitoring of the Darién documented single coyotes moving through the western edge of the area in 2016 and 2018. This leaves only the great Darién forests between coyotes and South America. If deforestation continues in the region, these two invasive canids could represent the first of a new, Not-So-Great American Biotic Interchange, where generalist species adapted to human disturbance cross continents and threaten native biota. [ABSTRACT FROM AUTHOR]

Landscape change affects the distribution of wildlife and represents a conservation concern, especially in Asia, which is experiencing rapid development. We examined the impacts of landscape change on corsac foxes in Mongolia. We addressed 2 questions: 1) how do common features of a landscape, such as habitats, topography, and human structures, shape the distribution of the species? and 2) how will the loss of those features affect distribution? We developed an occupancy model based on locations (n = 2,437) collected in Ikh Nart Nature Reserve, then estimated the marginal loss in average occupancy across the landscape when features were removed. The model with the most support indicated that occupancy was best described by the additive combination of open plain, tall grassland, and shrubland habitats. Average occupancy across the reserve was 22% under current conditions. Simulations involving the removal of each habitat resulted in a marginal loss of 12%, 35%, and 49% in average occupancy, respectively. The loss of all 3 habitats, as expected under climate change projections, will probably make the landscape unsuitable. The results provide the first model of corsac fox occupancy, which can be used to examine distribution and impacts of change in other parts of the species' range. They also suggest that managers should plan conservation activities to allow corsac fox distribution to shift northward as the region becomes warmer and drier and vegetation communities change. [ABSTRACT FROM AUTHOR]

Oral lesions in wolves (Carnivora: Canidae: Canis lupus) are usually reported in a nonstandardized manner, and often only a few abnormalities are indicated. This approach has likely led to underreporting of oral lesions, thus limiting our ability to interpret wolf health conditions and thus making comparisons across geographical and taxonomic groups difficult. Here, we present a standardized oral exam protocol to examine wolf skulls for their oral lesions. Using this protocol, we analyzed 40 skulls of adult wild Middle East wolves representing 1,680 teeth. Six wolves were Canis lupus arabs, 34 were Canis lupus pallipes. Only 3 skulls showed no oral lesions. We were able to identify a large range of oral lesions and refined subclasses, exceeding the variety of what has been reported on wolf oral lesions so far. No statistical differences were found in the type and number of lesions between the 2 subspecies of wolves. Therefore, the lesions were pooled in subsequent analyses. This standardized protocol should provide a useful framework to assess oral lesions in wolf skulls, facilitating rigorous comparisons across geographic and taxonomic groups. [ABSTRACT FROM AUTHOR]

The bush dog (Speothos venaticus) is a small Neotropical canid. Although its distribution covers the entire Amazon basin, the occurrence of bush dogs in vast areas of the Amazon remains hypothetical. The records of bush dogs presented in this study reduce a large gap in the known distribution of the species in Central Amazonia and include the 1st documentation of the species from forest seasonally flooded by black water (Igapó). [ABSTRACT FROM AUTHOR]

The social behavior of the smaller fox species is poorly known compared with that of larger and more gregarious canids that can be directly observed. We studied social relationships and reproductive behavior of island foxes (Urocyon littoralis) on San Clemente Island (SCI) and San Miguel Island (SMI), off the coast of Southern California, using proximity logging collars. On both islands, pair members interacted more frequently and spent more time together than other types of dyads. On SCI, a high contact rate identified the same 10 mated pairs that were identified by a high degree of home-range overlap. A high contact rate also identified 3 mated pairs on SMI, 2 of which were associated with large pups 9-10 months old. On SMI, the number of contacts and amount of time that mates spent together per day varied across months and peaked in February, when most conceptions occur. Mates spent much less trine together in April to June, the pup-rearing season. More unpaired male-female and male-male dyads interacted during January and February than in subsequent months. Paired males appeared to guard their mate during the period when she was receptive. The average duration of estrus was approximately 40 h. Paired females were in contact with other males in addition to their mate near the time they were presumably in estrus, and paired males were in contact with other females in addition to their mate. The relatively short duration of estrus, combined with asynchrony of estrus among females, enabled paired males to leave their mate and seek extrapair copulations without risk of cuckoldry. Proximity logging collars provide a new opportunity to learn about these temporal aspects of social and reproductive behavior in canids. [ABSTRACT FROM AUTHOR]

Virtually no information exists on the impacts of urban areas on island endemics. We examined the spatial distribution of island foxes (Urocyon littoralis clementae) associated with 3 small anthropogenically developed (i.e., "urban") areas and nonurban areas on San Clemente Island, California. Annual home range size averaged 0.84 km² (n = 25, SE = 0.07). Our top model indicated that foxes that spent a greater proportion of time in urban areas had significantly smaller home ranges (βPUrb = -0.009, 95% confidence interval [CI] =-0.0180-0.0002). We found no effect of sex (βSex = 0.0135, 95% CI = -0.1430-0.1700), age (βAge = 0.0502, 95% CI = -0.2730-0.3734), or whether or not a fox was considered a "road" fox (βRoad = -0.0063, 95% CI = -0.2638-0.2513) on home range size. We noted considerable overlap of home ranges of foxes that used urban areas. Foxes used urban areas a greater proportion of time during the night than during the day (t24 = -6.13, P < 0.001); however, foxes did not spend a greater proportion of time in urban areas than expected overall (t24=-0.59, P = 0.560). We observed 13 of 25 (52%) foxes that utilized urban areas feeding on anthropogenic food resources. Foxes that used urban areas were heavier (n = 35, ̄X = 1.98, SE = 0.05) than foxes that did not use urban areas (n = 26, ̄X = 1.81, SE = 0.04; t59 = -2.69, P = 0.009). Our study is the first to demonstrate the effects urban areas on islands may have on canid populations. our findings were similar to those reported for urban canid populations on the mainland, suggesting that future conservation and management of carnivores on islands may benefit from strategies that have been successful with mainland species. [ABSTRACT FROM AUTHOR]

Analyses of feces, stomach contents, and regurgitated pellets are common techniques for assessing diets of vertebrates and typically contain more than 1 food item per sampling unit. When analyzed, these individual food items have traditionally been treated as independent, which represents pseudoreplication. When food types are recorded as present or absent, these samples can be treated as multinomial vectors of food items, with each vector representing 1 realization of a possible diet. We suggest such data have a similar structure to capture histories for closed-capture, capture--mark--recapture data. To assess the effects of landscapes and presence of a potential competitor, we used closed-capture models implemented in program MARK into analyze diet data generated from feces of swift foxes (Vulpes velox) and coyotes (Canis latrans) in northwestern Texas. The best models of diet contained season and location for both swift foxes and coyotes, but year accounted for less variation, suggesting that landscape type is an important predictor of diets of both species. Models containing the effect of coyote reduction were not competitive (ΔQAICc = 53.6685), consistent with the hypothesis that presence of coyotes did not influence diet of swift foxes. Our findings suggest that landscape type may have important influences on diets of both species. We believe that multinomial models represent an effective approach to assess hypotheses when diet studies have a data structure similar to ours. [ABSTRACT FROM AUTHOR]

The maned wolf (Chrysocyon brachyurus) is the largest canid in South America, weighing up to 30 kg, and exhibits an omnivorous diet based on fruits and small vertebrates. Maned wolves are considered to live in monogamous pairs defending a common territory, with mates living a largely solitary life, but these conclusions come from few studies with small samples. We captured maned wolves in Emas National Park, central Brazil, and monitored their use of space using radiotelemetry. Home-range size and overlap of 45 adults, and interactions between members of 5 pairs, were investigated. Home-range sizes of resident adults averaged 80.18 km² using the fixed kernel with 95% of the locations, and averaged 13.78 km² with 50% of the locations. Overlap of 95% ranges between male-male, female-female, or mixed dyads was similar, approximately 0.20, whereas 50% ranges of maned wolves showed less overlap overall but more tolerance for overlap with the opposite sex. Members of a pair were located alone more often than together, and even when located simultaneously maintained a mean distance of >0.5 km apart, independent of time of day. Results are in agreement with a spatial organization based on monogamous mating pairs with little intrapair sociality, but the latter needs to be investigated in more detail. [ABSTRACT FROM AUTHOR]

The seasonal diet of Pampas foxes (Lycalopex gymnocercus) was examined from 431 scat samples collected during 1 year in the dry Chaco woodland of Salta Province, northwestern Argentina. Fleshy fruits dominated the diet during the dry and wet seasons, representing 69% of the total frequency and comprising 91% of the total volume. Most of the fruit diet was contributed by 5 woody plant species. Mistol (Ziziphus mistol, Rhamnaceae), was the most important fruit resource throughout the year. Arthropods (particularly beetles and scorpions) and small mammals (mainly rodents and marmosets) were the most frequently consumed animal prey. Seasonal shifts in the frequency of the main food items in the diet were not significant, but there was considerable seasonal variation in the frequency of fruit species. Diversity of prey in the diet was highest in the wet season. The Pampas fox is a generalist feeder that can alter its diet to changes in food availability. However, its diet in the Chaco, which is dominated by fruit, differs from its diet in Pampas grassland habitat, where it consumes mostly meat. [ABSTRACT FROM AUTHOR]

To test how interindividual variation in response to resource availability might reveal mechanisms leading to interpopulation variation across the geographic range of a species, we investigated movement patterns and use of space by 18 radiocollared raccoon dogs (Nyetereutes procyonoides viverrinus) in a mixed landscape of agriculture and forestry that is widely distributed in Japan, and that is a typical landscape for raccoon dogs. We tested the idea that the behavior of raccoon dogs, as ecological generalists, is sufficiently plastic for individual movement patterns to match habitat variation in this landscape. Home ranges averaged 111 ha (95% kernel estimate, much larger than previously reported for this species in Japan, and varied greatly among individuals (23--228 ha). Home ranges were 62.5% larger in autumn than in other seasons, and 33.5% larger fur subadults than for adults. Average movement rate tended to be higher in autumn (mean rate = 297 m/h), and lowest in winter (mean rate = 204 m/h). Within the population, some individuals occupied home ranges that were predominantly seminatural (we refer to these animals as "mountain type"), whereas those of others were dominated by heavily managed habitats (these we term "village type"). Within their home ranges, the types showed preferences for the habitats that were most prevalent there. Mountain-type individuals showed a preference for herbaceous habitat, whereas the village-type individuals used cropland disproportionately. Activity, as measured by the proportion of fixes designated active, tended to be lower in home ranges where cropland was predominant, and the magnitude of preference tot cropland increased with its availability with the home range, suggesting a functional response to habitat availability. The fractal dimension of movement trails was more complex in seminatural areas than in agricultural land, possibly reflecting greater spatial regularity of agricultural habitat. [ABSTRACT FROM AUTHOR]

Our previous investigations of some of the lesser-known canids suggested that deviations from the patterns exhibited by the more extensively studied species such as wolves and coyotes might be found in other canids. We used fecal estrogen and progestin profiles from captive colonies to describe the basic reproductive pattern of island foxes (Urocyon littoralis). Based on sustained increases in levels of fecal progestin as indicative of ovulation, we determined that 11 of 13 females housed with males ovulated. In contrast, we detected no ovulations in 10 females housed alone and only 1 possible ovulation among 10 additional females housed in female-female pairs. Of the 2 females with males that failed to ovulate, 1 did ovulate the subsequent year while with the same male, and the other failed to ovulate when paired with a yearling male, perhaps due to his immaturity and inexperience. Significantly higher fecal estrogen levels in ovulating compared to non-ovulating females suggest that estrus was induced by the presence of a male. However, these results cannot distinguish whether male-induced estrus was followed by an induced or spontaneous ovulation, because estrogen levels indicative of estrus were always followed by ovulation. Fecal cortisol levels did not differ by ovulatory status, indicating that ovulation was not inhibited by stress mediated by glucocorticoids. Our results are the 1st to provide evidence of induced estrus, perhaps followed by induced ovulation, in a canid species, features that could have selective advantage for this less social, more secretive canid. [ABSTRACT FROM AUTHOR]

Canids form the most widely distributed family within the order Carnivora, with members present in a multitude of different environments from cold arctic to hot, dry deserts. We reviewed the literature and compared 24 data sets available on the basal metabolic rate (BMR) of 12 canid species, accounting for body mass and climate, to examine inter- and intraspecific variations in mass-adjusted BMR between 2 extreme climates (arctic and hot desert). Using both conventional and phylogenetically independent analysis of covariance, we found that canids from the arctic climate zone had significantly higher mass-adjusted BMR than species from hot deserts. Canids not associated with either arctic or desert climates had an intermediate and more variable mass-adjusted BMR. The climate effect also was significant at the intraspecific level in species for which we had data in 2 different climates. Arctic and desert climates represent contrasting combinations of ambient temperatures and water accessibility that require opposite physiological adaptations in terms of metabolism. The fact that BMR varies within species when individuals are subjected to different climate regimes further suggests that climate is an important determinant of BMR. [ABSTRACT FROM AUTHOR]

Vocal individuality has been found in a number canid species. This natural variation can have applications in several aspects of species conservation, from behavioral studies to estimating population density or abundance. The swift fox (Vulpes velox) is a North American canid listed as endangered in Canada and extirpated, endangered, or threatened in parts of the United States. The barking sequence is a long-range vocalization in the species' vocal repertoire. It consists of a series of barks and is most common during the mating season. We analyzed barking sequences recorded in a standardized context from 20 captive individuals (3 females and 17 males) housed in large, single-pair enclosures at a swift fox breeding facility. Using a discriminant function analysis with 7 temporal and spectral variables measured on barking sequences, we were able to correctly classify 99% of sequences to the correct individual. The most important discriminating variable was the mean spacing of barks in a barking sequence. Potential applications of such vocal individuality are discussed. [ABSTRACT FROM AUTHOR]

Investigates the food items consumed by sympatric manned wolves, crab-eating foxes and haory foxes in the Cerrado biome of central Brazil to determine overlap among their diets. Home ranges and spatial segregation among the canids; Determination of the importance of each food item through relative frequency; Habitat use by the canids.

Presents a discussion on the importance of a better understanding of the relationship between San Joaquin kit foxes (Vulpes macrotis mutica) and larger canids that prey on them. Monitoring of survival and cause of death on the Carrizo Plain Natural Area, California; Other contributing factors that decreases kit foxes' population; Vulpes macrotis mutica; Canis latrans; Intraguild predation.