Recent work on tropical montane small mammals and birds has shown that abundance–elevational range size relationships (i.e., the relationship between abundance of a species and its elevational range size) can be manifested in a number of distinct generalized patterns. To understand why different patterns occur, one first must understand the causal mechanisms behind patterns of interspecific variation in species abundance and elevational range size. Using small mammal data along five elevational gradients in Southwest China, we assessed the relative importance of body mass, niche position (i.e., how typical the environmental conditions in which a species occurs are of the full set of conditions under consideration) and niche breadth in explaining the interspecific variation in mean abundance of species of small mammals, and elevational range size. Niche position and niche breadth were calculated using outlying mean index analysis based on 24 environmental variables. The relative importance of body mass, niche position, and niche breadth, in explaining the mean abundance and elevational range size of species were examined using phylogenetic regression and phylogenetic path analyses. Along each of five elevational gradients, body mass maintained a nonsignificant (P > 0.05) relationship both with mean abundance and elevational range size when the effects of phylogeny were taken into account. Niche position had a negative effect on mean abundance and elevational range size (species with a niche position close to edge environmental conditions were rarer and had smaller elevational range sizes) across five gradients (significant negative effect: three gradients for mean abundance; five gradients for elevational range size). Conversely, a positive effect of niche breadth on mean abundance and elevational range size was observed consistently, yet the effect was significant only for some gradients (mean abundance: two gradients; elevational range size: four gradients). Our study suggests that niche position and niche breadth both are good predictors of abundance and elevational range size of montane small mammals; niche position and niche breadth therefore play a strong role in the formation of abundance–elevational range size relationship.

Rock-dwelling pikas of the genus Ochotona have fragmented montane geographical distribution presumably associated with geological and climatic events of Late Quaternary. Within this genus, the northern pika, O. hyperborea has the widest distribution. Taxonomic composition and subspecific structure of this species has been controversial during the past century. Sixteen available names were combined in different manners into a variable number of weakly overlapping subspecies by previous authors. A comparison of data sets from the entire distribution range of northern pikas is presented here for the first time, including: craniometric, bioacoustic, and multilocus genetic data. We examined 301 skulls, and the mitochondrial COI gene and two nuclear introns in 79 specimens, as well as the structure of alarm calls from 107 individuals. Our results show that the six subspecies within O. hyperborea correspond to the six genetic parapatric lineages. Five of these are hypothesized to be involved in hybridization at the edges of their distribution. Three acoustic races completely correspond with the six genetic lineages: each acoustic race consists of two lineages. Morphometric data do not display any phylogenetic signal in our study. The subspecies from the Mountains of Khabarovsk Territory, north of Amur River, is described de novo as O. h. fedoseevi ssp. n. The type locality of O. hyperborea is defined more accurately. A neotype is designated for O. h. cinereofusca to stabilize use of names of pikas from the Amur region.

Cryptic species, defined as those that are morphologically indistinguishable but phylogenetically distinct, are common in bats and correspond to the majority of newly described species. Such seems to be the case of Glossophaga soricina, a generalist, glossophagine bat that is broadly distributed throughout the Neotropics. Several studies have found high levels of molecular variation within G. soricina, suggesting that it could be a cryptic species complex. Here, we explore data derived from two-dimensional geometric morphometric analyses of cranial characters and their covariation with environmental variables, aiming to test the existence of more than one species grouped within it and to contribute to the knowledge of its variation and evolutionary history. Variation in shape and size of skull and mandible supports the two main mitochondrial lineages reported in previous studies, one corresponding to the east side of the Andes (subspecies G. s. soricina) and the other one corresponding to populations from Mesoamerica and the west side of the Andes, in turn composed of at least three monophyletic and morphologically differentiated taxa. Environmental variables correlate with shape variation and might be responsible for convergences in shape and size between the species with the smallest distributions. Based on the evidence we present in this work we elevate four subspecies to the taxonomic level of species. The correct names for the species of the analyzed complex are: G. soricina (Pallas 1766), G. muticaMerriam 1898, G. antillarumRehn 1902, and G. valensMiller 1913.

The sigmodontine rodent Oecomys catherinae has been recognized as a species complex that includes five different lineages distributed throughout Brazil south of the Amazon river, named in literature according to their geographic position (central, eastern, northern, western, and westernmost). The western lineage also has been referred as Oecomys aff. catherinae in the literature, because it may represent a distinct species. Herein, we used molecular and morphological data to investigate the possible species distinctiveness within the O. catherinae complex. From molecular analyses, we recovered the western lineage as a monophyletic group with high genetic divergence from the other lineages of the complex. This lineage can be differentiated from other lineages of the O. catherinae complex and other congeners through a combination of mensural and morphological characters that includes: smaller size; posterior margin of nasals usually surpassing the maxillary–frontal suture; supraorbital crest moderately developed, similar to the temporal crest; parietal slightly expanded laterally; subsquamosal fenestra present; alisphenoid strut absent; and anterior cingulum of M1 present. The western lineage occurs in the southern Amazonia, in sympatry with the westernmost lineage and other species of Oecomys. Herein we describe this lineage as a new species, increasing to 19 the number of species within Oecomys.

The Vampyressa melissa species complex comprises three rare bat species poorly represented in museum collections. Vampyressa melissa and V. sinchi are restricted to the eastern slope of the Andes, while V. elisabethae only is known from Panama, in Central America. The species complex has received recent attention in terms of systematic reviews, which concluded in the description of two species: one from Panama (V. elisabethae) and one from Colombia (V. sinchi). Vampyressa melissa recently was reported from the eastern slopes of the Cordillera Oriental of Colombia, in the department of Casanare. However, morphological and genetic (Cytochrome b) comparisons showed that these specimens belong to an undescribed species of the genus. The new species is the smallest member of the V. melissa complex and has a unique set of morphological characters compared to other Vampyressa species. Molecular evidence shows that the new species is sister to V. melissa (sensu stricto) from Colombia and Peru, albeit with high genetic divergence (7.9%). Nevertheless, Cytochrome b sequences of V. elisabethae and V. sinchi still are unknown. This new species increases to six the number of species in the genus. Vampyressa melissa, V. sinchi, and the new species, exhibit restricted distributions in the eastern slopes of the Andean Cordillera, in specific altitudinal ranges. Because of geographic constraints, their biological rarity, and the high deforestation rates in their distributional area, we suggest that these three species must be considered as taxa threatened with extinction.

During a faunal survey in the foothills of the Ecuadoran Andes southwest of the Cordillera del Cóndor, a mouse of uncertain affinities was taken in a fishing net. Various external characters suggested that it was a member of the genus Rhagomys, previously unrecorded in Ecuador. Comparisons with the external, cranial, and dental morphology both of Rhagomys rufescens and R. longilingua identified a number of unique characters, including its long, narrow rostrum and incisive foramina and the reduced anterolingual conule on its M1 procingulum. We describe the mouse as a new species of Rhagomys; both its morphology and molecular analyses suggest that it is sister to R. longilingua. This record of Rhagomys in southern Ecuador extends the known distribution of the genus 700 km northward and adds yet another genus and species to Ecuador's extensive list of rodent species.

We combine morphological (qualitative and quantitative data) and genetic (one mitochondrial and one nuclear gene) data from a large set of specimens of Octodon from the four currently recognized living species of the genus. The integration of the results (qualitative assessment, multivariate analysis of cranial measurements, and gene trees) allows us to state that 1) the current taxonomic scheme does not reflect the species diversity of Octodon; 2) in particular, as currently understood O. bridgesii likely is a complex of three species; 3) one of these, encompassing the southern populations of the genus, in the Araucanía Region (Chile) and Neuquén Province (Argentina), is named and described here as a new species; and 4) the mitochondrial gene tree departs from the nuclear gene tree with respect to O. pacificus and the new species here described.

While hypsodonty mostly is associated with medium to large body sizes in sigmodontine rodents, high-crowned molars combined with small bodies rarely are recorded. This latter condition is present in Neomicroxus (Sigmodontinae, incertae sedis), a genus of high-Andean cricetids also characterized by a noticeable set of cranial traits, including enlarged turbinals and rostrum, slanting zygomatic plate, and a marked backward displacement of the vertical ramus of the dentary, linked with an enlargement of the basicranial region. These morphological features, combined with the isolated position of this lineage in molecular-based phylogenies, indicate that Neomicroxus should be situated in a new tribe. We name and describe this Páramo novelty monotypic clade here. As a working hypothesis, the hypsodonty displayed by this group is considered an evolutionary response to continued volcanic ash falls that characterized the region during the Neogene. A reappraisal of tribe recognition within the two cricetid largest subfamilies, arvicolines and sigmodontines, is made, coupled with a discussion about the role of morphological convergence in “long-nose” cricetids.

The montane sky islands of the Great Basin are characterized by unique, isolated habitats and communities that likely are vulnerable to extirpation with environmental change. A subspecies of yellow pine chipmunk, the Humboldt yellow pine chipmunk (Tamias amoenus celeris), is associated with the whitebark and limber pine forests of the Pine Forest Range (PFR) in Nevada. We sampled T. amoenus and least chipmunks (T. minimus) from the isolated PFR and compared genetic diversity between these populations and more “mainland” populations, including other subspecies of chipmunks. Given the high frequency of hybridization in Tamias, we tested for hybridization between T. amoenus and T. minimus in the PFR. We examined phylogenetic relationships, population divergence and diversity, and screened populations for a common pathogen, Borrelia hermsii, to gain insight into population health. We found T. amoenus of the PFR are closely related to T. amoenus in the Warner Mountains and Sierra Nevada, but maintain substantively lower genetic variation. Microsatellite analyses show PFR T. amoenus are highly genetically differentiated from other populations. In contrast, PFR T. minimus had higher genetic diversity that was comparable to the other T. minimus population we sampled. Pathogen screening revealed that T. amoenus carried higher pathogen loads than T. minimus in the PFR, although the prevalence of infection was similar to other Tamias populations. Our assessment of habitat associations suggests that the Humboldt yellow pine chipmunk almost entirely is restricted to the conifer systems of the PFR, while least chipmunks are prevalent in the other forests. Our work highlights the need for continued conservation and research efforts to identify how response to environmental change can be facilitated in isolated species and habitats.

Global climate drivers often have strong effects on the carrying capacity of animal populations, but little is known about how effects differ between regional and local scales. In this paper we evaluated how climate variables were correlated with regional and local fluctuations of a small rodent, Necromys lasiurus, in an Amazonian savanna. Between 2000 and 2019, we evaluated the temporal variation in abundance of N. lasiurus in eight 4.0-ha plots separated by 0.8 – 10.6 km. Using generalized linear mixed models, we found that, at a regional scale, the abundance of rodents captured was positively associated with the abundance in the prior year, but had little relationship with the Southern Oscillation Index (SOI), which had been shown to affect rats in a single plot in a previous study. However, variation in densities among years was coordinated among some plots, leading to patchiness in population dynamics. Based on the patterns of density fluctuations, the plots formed three clusters. Analyses based on these clusters indicated that only one was strongly affected by SOI, as in the previous study. The differences in the effects of global climate drivers on populations of a single species in relatively homogeneous habitat indicate that predictions about the effects of climate change should be based on simultaneous studies in a variety of sites or they may lead to spurious relationships.

Assemblages of Neotropical frugivorous bats are structured as a function of the fruit diets of species; however, ecological relationships among closely related species largely remain unknown. This study evaluated the trophic relations among three species of Carollia in a premontane forest of central Peru. To accomplish this, we first determined the diet composition of frugivorous bats to build a bat–fruit interaction network. We then assessed the trophic structure of the bat assemblage using a modularity analysis in the network. Carollia brevicauda and Carollia perspicillata were grouped apart from Carollia benkeithi. This partition occurred because the diet of C. benkeithi was more specialized, characterized by two Piper species, a Cyclanthaceae species, and Banara guianensis. Moreover, C. benkeithi, in contrast to its congeners, did not consume fruits of Ficus or Cecropia (canopy resources). This result and available information on the ecology of Carollia species suggest that small species of Carollia are more likely to carry out most of their feeding activities in the understory than are large species of the genus.

Genetic variability generally is associated with adaptive potential of species and can be assessed using microsatellite markers. Mexican long-nosed bats (Leptonycteris nivalis) are endangered, migratory nectarivores thought to be experiencing population declines. Despite historical and current tracking efforts, migratory connections among roost sites remain elusive. Our objective was to assess the genetic variability and connectivity of two of the most geographically separated populations of L. nivalis currently known—a mating roost in central Mexico used from September to March, and a maternity roost in western Texas used by adult females and their young from June to August. Twelve loci developed for L. yerbabuenae and four for Glossophaga soricina amplified L. nivalis DNA; of those 16 loci, seven (all from L. yerbabuenae) were useful in genetic analyses of 113 individuals. High levels of genetic variation in L. nivalis from the two sites were not significantly different and no substructure was detected between these two roost sites separated by more than 1,200 km. Further, we recovered evidence of close relationship (parent–offspring) in nine pairs of juveniles captured at the northern roost and adults from the southern roost, confirming a connection between the two locations. For this endangered species, the level of variation detected, the lack of a recent bottleneck, and estimates of effective population size, are encouraging for future recovery. Management plans aimed at conserving Mexican long-nosed bats should recognize the need for managing these bats as a single population and conserving foraging and roosting habitat along migratory routes to reduce population fragmentation.

Patterns of selection in South American camelids (Lamini) and their unique demographic history establish the llama and alpaca as remarkable cases of domestication among large herd animals. Skull shape is implicated in many changes reported between wild and domestic taxa. We apply 3D geometric morphometric methods to describe skull shape, form, and size, differences among the four species of Lamini. In so doing, we test if domesticated Lamini exhibit changes similar to those in other domesticated groups: not only in the skull, but also in brain and body size. In contrast to other domesticated artiodactyls, very little change has occurred in domestic alpacas and llamas compared to their wild counterparts. Nevertheless, their differences are statistically significant and include a flatter cranium, inclined palate and increased airorhynchy in the domestics. Selection pressures that contrast with those on other herd animals, as well as recent population bottlenecks, likely have influenced the morphological patterns we note in Lamini. High-resolution 3D morphospace allows skull size, shape, and form (shape + size), to discriminate all four species, with form providing the greatest separation. These results help differentiate morphologically the Lamini, which in nature are distinguished mainly by body size, and provide an additional tool to archaeologists for distinction of wild and domestic remains. Most of our shape analyses suggest a marginally closer relationship between the alpaca and vicuña, to the exclusion of the guanaco, supporting the genetic relationships for this group. The expected brain size change between wild and domestic populations is lower than previously thought, with a 15.4% reduction in llama, and 6.8% reduction in alpaca. This is the lowest reduction in brain size thus far reported among domesticated Artiodactyla.

Developing morphological diagnoses for fossil mammals requires an understanding of intraspecific variation in the anatomical elements under study. Dental traits along with tooth size can be informative of taxonomic identify for extinct species. However, it is unclear what selective or developmental processes are responsible for documented patterns in tooth-size variation making application to the fossil record difficult. We assessed combined species tooth-type variation and intraspecific tooth-size variation for 19 species to evaluate whether developmental controls or occlusion-driven functional demands influence carnivoran tooth-size variation. We also estimated phylogenetic signal for the coefficient of variation (CV). Combined species tooth-size variation separated by tooth type shows that canines are more variable than molars and lower premolars. We found intraspecific tooth-size variation patterns differ between species. However, comparisons of the CVs did not support the hypotheses that developmental controls or functional demands of occlusion constrain size variation in mammal teeth. Our results suggest that a combination of factors influence carnivoran tooth-size variation, such as differences in ontogeny, diet, sexual dimorphism, and evolutionary history. Patterns of carnivoran intraspecific tooth-size variation suggest a better understanding of dental size variation in extant species is essential for accurate morphological studies of fossil taxa.

Geomagnetic sensitivity is present in a variety of vertebrates, but only recently has attention focused on subterranean mammals. We report the potential use of a magnetic compass in wild Damaraland mole-rats (Fukomys damarensis) during dispersal at two sites in the Kalahari region of South Africa. When the distance traveled was greater than 250 m, males and females dispersed in opposite directions and females preferentially chose a predominantly northeastern direction. This directional choice likely is due to the differing dispersal tactics between sexes. This evidence suggests that Damaraland mole-rats employ a magnetic compass during aboveground dispersal to assist in locating mates or a new territory. This study provides evidence to show how magnetic compass use could be useful in dispersal, an important ecological process for mammals.

In human-dominated landscapes throughout the world, wildlife seek out anthropogenic foods because they are high in nutritional value and are consistently available. To investigate this mode of foraging, some researchers use stable isotope analysis to detect these animals in populations and estimate their individual diets. In this study, we develop an integrative approach to measure the proportion of corn, a C₄ plant, in the diets of free-ranging mammalian omnivores in C₃-dominated ecosystems. We fed captive mice corn, C₃ plants, and meat until carbon stable isotopes (δ¹³C) from each diet equilibrated in their hair. We then used carbon discrimination factors (Δ¹³C; offsets between stable isotope values of consumer tissues and their foods) for mice from these feeding trials and a simple carbon stable isotope mixing model to estimate the corn-based diets of free-ranging American black bears in Wisconsin and brown bears in Slovenia. We used Δ¹³C factors for mice to estimate the diets of bears because mouse models are used commonly to study mammalian diet and health, including humans and bears, and body mass has no effect on carbon discrimination factors in monogastric mammalian omnivores. In this study, we found that mice grew fastest, largest, and δ¹³C values equilibrated quickest in the hair of mice fed meat versus plant-based diets, suggesting protein quantity (quality was the same) has an effect on Δ¹³C. Evidence also suggests that Δ¹³C did not increase with animal growth rate as all mice grew throughout the 109-day feeding trials, but isotopic equilibration occurred early while mice still were subadults and was maintained throughout their adult lives. We also found that Δ¹³C was highest and most variable in the hair, serum, and liver, of mice fed a mixed diet of C₃ plants, supporting our mixed diet hypothesis that states that Δ¹³C varies more among tissues of animals fed mixed diets than animals fed nonmixed diets because the former are composed of multiple foods, each with different macromolecular and isotopic compositions. Lastly, we found that corn may have been a more important component of bear diets in Wisconsin than previously thought (adults: x̄ = 29%; x̄ = 33%; subadults: x̄ = 22%; x̄ = 28%), and male brown bears may have fed on 50% more corn (x̄ = 47% versus 31%) in autumn during a year when beechnut availability was low. In a world that is rapidly changing, it is more important than ever to develop the appropriate quantitative tools to measure the impact people have on wildlife. Here, we provide such a tool for monogastric mammalian omnivores and encourage other researchers to do the same for other taxa of interest.

Alternative reproductive tactics occur when conspecifics of the same sex use different behavioral processes to maximize reproductive success. Resource availability can have significant impacts on the proximate factors impacting the success and persistence of alternative tactics, such as an individual's physiology, immunity, and body condition. Male Cape ground squirrels (Xerus inauris) display two alternative tactics, with some mature males dispersing from their natal groups and joining bands of nonrelated males (band males), whereas others do not disperse and remain philopatric in their natal groups past sexual maturation (natal males). Despite differences in metabolism, home ranges, and behavior, there is no difference in reproductive success between the two tactics, allowing us to test if rainfall (as a measure of primary productivity) influences body condition and physiological indices in tactics when fitness is equal. Over a period of 6 years, rainfall was positively related to body condition (mass–spine length residuals) in band males (N = 76), but not in natal males (N = 75). When we followed 18 males prior to and after dispersal, we also found a positive relationship between body condition and age following dispersal, but not prior to dispersal, and natal males maintained a better body condition in low rainfall years. During 2 years of low rainfall, band males (N = 39) had higher total ectoparasite abundance, and white blood cell differentials, implying they are less able to tolerate parasitic infection than natal males (N = 31). We found no difference in bacterial growth inhibition between tactics, suggesting that band and natal males both are equally resistant to parasites. The poorer body condition of band males during lower rainfall suggests they are less tolerant to parasites in these years. Dispersal during years of low rainfall thus may increase the costs to body condition and parasite infection, but the reproductive benefit of overlapping with more females may contribute to maintaining equal fitness between tactics.

Studying how different environmental parameters, such as resource availability and ambient temperature, affect growth rates aids to understand the evolution of different growth strategies. Low levels of food availability restrict growth, and high ambient temperature can constrain growth via trade-offs between body temperature maintenance and heat produced during digestion. We studied growth of African striped mice (Rhabdomys pumilio), a small mammal living in a seasonally arid habitat. Striped mice are born during spring with high food availability and low ambient temperature, and typically enter the food-restricted dry season before reaching adulthood. We predicted low food availability and high ambient temperature would negatively affect growth. We therefore expected an extended period of slow growth during the long dry season. We repeatedly measured body length of 369 free-living individuals, examined how ambient temperature and food availability influenced growth rate, and seasonal changes in growth rate. In addition, we investigated whether mice (N = 27) born in summer (atypical breeding season) have slower growth rates than those born in spring. Growth rate increased with increasing food availability and decreased with increasing ambient temperature. Individuals born in summer grew slower than those born in spring. Sexes reached asymptotic body length at 258 days (females) and 285 days (males), which is an unusually long growth period compared with other small rodents. As most striped mice live for less than 1 year, this period encompasses the entire life for most individuals, but stops at old age, which could indicate senescence. Our results demonstrate a positive influence of food availability on growth, a relationship mediated by ambient temperature. We conclude that striped mice enter the food-restricted dry season before postnatal growth is terminated, and early exposure to harsh environmental conditions during the long dry season likely explains the prolonged growth period in striped mice.

Ecological niche models (ENMs) predict where species can occur in accordance with environmental factors. Suitability maps are generated through models to identify habitats more or less adapted to the species. Published works on the distribution and habitat use of Guiana dolphin, Sotalia guianensis, are limited to fine spatial scales. Here, we aimed to predict the potential geographical distribution of Guiana dolphins through ENMs and generate a map of suitable habitats for the species. Data were collected between 1997 and 2015 in Brazil, French Guiana, and Colombia. The environmental data were obtained from MARSPEC database with a cell resolution of 10 × 10 km. For modeling, 99 of the 859 initial occurrence points of the species were considered after rarefaction. Seven environmental variables were selected through factorial analysis: bathymetry, distance to shore, bathymetric slope, sea surface salinity (minimum monthly and annual range), and sea surface temperature (mean annual and annual range). Results from five distinct algorithms were assembled to generate the distribution model. Our findings show potential areas in shallow platforms of the continental margin of South and Central America, including regions where the species has never been reported, such as the Pacific Ocean, the Gulf of California, the Gulf of Mexico, and the oceanic islands in the Caribbean Sea. The absence of Guiana dolphins in these regions may be due to geographical (linking of North and South America), physical (water temperature), and biological (competition, limited ability to dispersal) limiting factors. The models suggest that the presence of other species of coastal dolphin may be an important limiting factor for the Guiana dolphin at both extremes of its distribution. The Guiana dolphin is habitat specialist with a clinal potential geographic distribution concentrated in tropical and subtropical shallow and coastal waters of the continental shelf of the western Atlantic Ocean. This more restricted distribution than reported by IUCN and other studies suggests a cautionary approach to its conservation status due to limited dispersal abilities and high overlap with human activities.

The expansion of human activity forces species to co-exist with people in human-modified landscapes (HMLs). However, living in HMLs demands behavioral adaptations, and the proximity between wildlife and people heightens human–wildlife conflicts. Capybara (Hydrochoerus hydrochaeris) is a thriving rodent species in HMLs in Brazil and as such, is involved in human–wildlife conflicts, such as vehicle collisions and transmission of Brazilian spotted fever (BSF). Despite their public importance, the effects of HMLs on capybara movement behavior have never been investigated. Our study aimed to investigate changes in home range, ranging pattern, and activity, for capybaras in six HMLs and two natural landscapes (NLs) by monitoring capybaras with GPS collars. We found home ranges 2.43 times greater in NLs than in HMLs and differences in ranging pattern in HMLs. Capybaras tended to be more nocturnal and move shorter distances across HMLs than NLs. Our results confirm the impacts of the HMLs altering capybara movement. The aggregation of capybaras in very small home ranges might imply on greater risks of tick infestations. In addition, capybara–vehicle collision may be increased during capybaras' nocturnal activity. Therefore, we recommend that transportation agencies avoid the construction of transportation infrastructures (roads, railways, airstrips) in capybaras' home ranges, which should be of restricted access to people in BSF endemic areas.

Coexistence of sympatric felids is facilitated by mutual avoidance and the partitioning of habitats, prey, and time. Anthropogenic disturbances disrupt this coexistence in fragmented landscapes, potentially triggering cascading influences in ecological communities. We used photographic data from 8,717 trap nights (November 2014–June 2016) at 87 camera trap sites in Colombia's middle Magdalena River basin to compare spatiotemporal overlap among jaguars (Panthera onca), pumas (Puma concolor), their prey, and humans, at sites of high and low disturbance, as determined by the human influence index. Human disturbance events (e.g., domestic dogs, livestock, and humans, including armed hunters) comprised 38% of all photographs at high disturbance sites and 29% of all photographs at low disturbance sites. Differential spatiotemporal overlaps were recorded between felids and their prey at high versus low disturbance sites, with jaguars exhibiting only 13% temporal overlap with humans at high disturbance sites. Among prey, temporal overlap was greater than spatial overlap for both felids across the study area. Compared to jaguars, pumas displayed more temporal overlap with all anthropogenic variables and more spatial overlap with most anthropogenic variables, suggesting lesser sensitivity to human disturbances. This study provides the first insights into the responses of a threatened large carnivore, jaguar, to camera trap-derived human disturbance variables in an unprotected landscape. It also highlights the importance of using multiple disturbance types for evaluating human impacts on large carnivores.

Subterranean rodents spend most of their lives in underground burrow systems, and most studies to date on their morphological, behavioral, and physiological, adaptations have been based on their whole-life existence in subterranean ecotopes. However, a few studies have reported that some subterranean rodents exhibit aboveground activity under particular circumstances, and the results of these studies help zoologists to better understand the adaptations of subterranean rodents coping both with belowground and aboveground environments. These studies, however, do not include direct observations of the aboveground activity of these rodents. Moreover, studies into the factors that influence the movement of these subterranean rodents outside of their burrow systems are relatively scarce. Here, we report the aboveground activity pattern of plateau zokor (Myospalax fontanieri) based on videos and photographs captured by infrared cameras combined with radiotracking technology in the eastern Qilian Mountains, northwest China. In addition, the potential factors that influence the aboveground activity of plateau zokor, including temperature, humidity, food, dispersal, and mating, were studied in 2015 and 2016. We found that, of the 16 zokors with radiocollars, five females moved aboveground during the day and night in June and July 2015, with the frequency of their aboveground activity being higher during the day than that at night. Temperature, humidity, mating, and dispersal, had no effects on aboveground plateau zokor movement. However, results of a binary logistic regression indicated that the crude fat contents of aboveground and belowground plants were positively and negatively correlated with the aboveground activity of these zokors, respectively. We infer that plateau zokor move on the ground to forage for plants with higher fat content and that changes in available nutrients might serve as potential cues that affect the surface activity of plateau zokor.