In agroecosystems, the use of cultivated plots by mammals depends on habitat structure as well as on the degree of species specialization. In the Pampas of Argentina, during the last 2–3 decades, there has been a continuing expansion of cropland. The aim of this study was to analyze how the identity and characteristics of agricultural plots may have affected the activity of 2 species of armadillos (Chaetophractus villosus and Dasypus hybridus) in a rural landscape. We carried out 4 sampling sessions between December 2011 and June 2013, surveying 175 plots during spring–summer and 194 during fall at 25 different sites in the Pampas of Buenos Aires province, Argentina. In each plot, we surveyed for signs (burrows and holes) along a 600 × 6 m transect in order to assess armadillo activity and measured 4 habitat structural variables. As expected, there were structural differences between types of agricultural plots. Across all plots, a total of 6,654 armadillo signs were found (C. villosus = 5,009, D. hybridus = 1,645). Generalized linear mixed models revealed that during both seasons, the type of plot explained much of the variation in armadillo activity, except during spring–summer for D. hybridus. C. villosus had higher use of plots with a longer history of non-tillage (e.g., soybean), while there was more evidence of D. hybridus activity in plots with less human intervention (e.g., grasslands), especially during fall. Overall, D. hybridus and C. villosus were more sensitive to the particular structural features of plots rather than to the kind of land use practiced (crop field or rangeland). These results have important implications for future management decisions in the Pampas region because during the last decades, farming of soybeans has expanded at the expense of grasslands, and this change appears to have differentially affected these 2 species of armadillos.

Determining social contacts among solitary carnivores is difficult given their often nocturnal and secretive nature. We used proximity-sensing radiocollars to quantify social contacts and den sharing among striped skunks (Mephitis mephitis) in suburban Flagstaff, Arizona, United States, in summer, autumn, and winter 2012–2013. During June and July, we followed 6 males and 5 females and, in spite of overlapping home ranges, they had few social contacts (range = 0–7), and all were brief, nocturnal encounters. From October through February, we followed 8 males and 9 females and found that patterns of contacts were similar for males and females except for significantly higher diurnal contacts (co-denning) among females in winter. Females varied in denning behavior; 1 female denned continuously in the same location from early November to late January, while at the other extreme 1 female moved among 10 different dens across the same time period. Several females moved to new communal dens in late January, resulting in new combinations of females co-denning. Males visited multiple female dens throughout winter. Overall, our data were consistent with previous studies in documenting overlapping home ranges of both sexes with few social contacts in summer, male intolerance but lack of male territoriality, and divergent social behavior in winter, with females co-denning while males generally denned alone. Our study differed from others in documenting more social interaction and movement during winter, often through nocturnal visits by males to female dens, and a shift in denning associations among females near the end of January.

For animals that forage widely, protecting young from predation can span relatively long time periods due to the inability of young to travel with and be protected by their parents. Moving relatively immobile young to improve access to important resources, limit detection of concentrated scent by predators, and decrease infestations by ectoparasites can be advantageous. Moving young, however, can also expose them to increased mortality risks (e.g., accidents, getting lost, predation). For group-living animals that live in variable environments and care for young over extended time periods, the influence of biotic factors (e.g., group size, predation risk) and abiotic factors (e.g., temperature and precipitation) on the decision to move young is unknown. We used data from 25 satellite-collared wolves (Canis lupus) in Idaho, Montana, and Yellowstone National Park to evaluate how these factors could influence the decision to move pups during the pup-rearing season. We hypothesized that litter size, the number of adults in a group, and perceived predation risk would positively affect the number of times gray wolves moved pups. We further hypothesized that wolves would move their pups more often when it was hot and dry to ensure sufficient access to water. Contrary to our hypothesis, monthly temperature above the 30-year average was negatively related to the number of times wolves moved their pups. Monthly precipitation above the 30-year average, however, was positively related to the amount of time wolves spent at pup-rearing sites after leaving the natal den. We found little relationship between risk of predation (by grizzly bears, humans, or conspecifics) or group and litter sizes and number of times wolves moved their pups. Our findings suggest that abiotic factors most strongly influence the decision of wolves to move pups, although responses to unpredictable biotic events (e.g., a predator encountering pups) cannot be ruled out.

In many mammals, the skin of the rhinarium includes a thick epidermal layer. The skin surface can be smooth but can also display a structure formed of domes, ridges, and polygonal areas: a dermatoglyphic or rhinoglyphic pattern. Each structure consists of an easily visible, large area of the epidermis. The abdominal epidermis may or may not have a dermatoglyphic pattern. The abdominal skin examined in our study had no pattern and was consequently unstructured and smooth. The ultrastructural surface pattern is formed in the granular and corneous regions of nasal epidermis by desmosome protrusions projecting into adjacent keratinocytes. Complete retraction of the keratinocyte protrusions with desmosomes in the abdominal epidermis creates an unstructured, smooth surface. The cornification process differs morphologically in nasolabial and abdominal skin. In this study, we report a novel structure in the nose skin. It is related only to the surface of a single corneocyte (keratinocyte) and consists of submicrometer pores or furrows, an ultrastructure pattern. It is not related to the rhinoglyphic pattern. The nose skin can thus have 2 unrelated patterns. This structure seems to be widespread among the Mammalia. We suggest the function of the structure is to keep the rhinarium evenly moist.

The intrinsic autopodial musculature of mammals is composed of a relatively stable number of muscular groups. Here, we present the first myological studies of Lyncodon patagonicus, a South American mustelid that is morphologically and ecologically poorly known. The typical intrinsic muscles of the manus of Lyncodon are similar to those of its sister taxon Galictis, although there exist few variations, including additional subdivisions and relatively more distal insertions in some muscles. A striking feature is the presence of a novel series of forepaw muscles never before described for mammals. These muscles, named here mm. flexores digitorum proprii manus, are represented by a medial and a lateral belly for each digit and are located immediately distal to the mm. flexores breves profundi. They are located distally alongside the tendons of the latter, along the palmar aspect of the phalangeal series, and they insert onto the flexor tubercle of the distal phalanx of each digit. We propose that the incorporation of these muscles in the forepaw musculature of Lyncodon, in addition to some other osteo-myological features, imply a distinctive morpho-functional adaptation to increase the force of flexion and independence of digital movements likely used to grasp prey during hunting. This hypothesis should be confirmed by future ecological and behavioral studies on this species.

Weaning in mammals is typically thought of as the transition from reliance on maternal milk to feeding independently. Current theory suggests a complex process involving mothers imparting enough resources to offspring as to ensure survival without compromising both prior and future reproductive efforts, and the demands of offspring whose primary concern is survival. Otariid seals are a suitable group to study this given the morphological and behavioral similarities across species of the primary care giver, adult females. At higher latitudes, the duration of maternal care is short and tightly linked to seasonal productivity of the marine environment, punctuated by a predictable migration of mothers away from breeding sites. In contrast, nonmigratory temperate latitude otariid species have a much wider range of lactation periods, with mothers prolonging maternal support in relation to seasonal unpredictability of food resource. Prolonging care into the subsequent reproductive effort will likely have profound effects on the survival of the younger offspring. The Australian sea lion Neophoca cinerea has broken the phylogenetic constraint of a 12-month breeding cycle, which may reflect an alternate strategy to reduce the fitness costs of prolonged support by providing up to 18 months nutritional support to offspring. We use stable isotope analysis of temporally matched whisker sections combined with telemetry data on nutritionally dependent Australian sea lion pups to determine the weaning process and characterize the transition to nutritional independence. Using changes in isotopic nitrogen (δ¹⁵N) over time, pups undergo a gradual transition to independent foraging during a 3- to 6-month period before the onset of the next reproductive effort. Telemetry data supported this conclusion, indicating benthic foraging of weaned pups in areas consistent with adult female foraging.

Water conservation is challenging for terrestrial life since water is continuously lost through respiration, excretion, and cutaneous evaporation. Total evaporative water loss (TEWL) is an important component of the water budget. In general, TEWL is mainly determined by biophysical mechanisms, such as ambient temperature (T_a) and humidity. However, it has also been suggested that TEWL can be actively regulated in the short term to confront environmental conditions and be further modified by development and acclimation. Thus, regulation of TEWL might be complex, especially in semifossorial species, which continuously meet contrasting conditions at the surface. We evaluated the influence of acclimation to different ambient humidities on TEWL and associated metabolic parameters in the subterranean rodent Ctenomys talarum. We found that changing humidity acclimation conditions may not elicit modifications on TEWL. Both the water vapor–saturated burrows and the stability in TEWL at different humidities would lead to overheating problems at high ambient temperatures. Then, other forms of heat loss such as dry conductance may be enhanced. Fossoriality apparently evolved as a way of surviving increasing aridity conditions; therefore, other behavioral adjustments might be employed to counteract the high humidity within burrows.

In this study, we name and describe a new species of the genus Necromys from northwestern Argentina based on molecular (mtDNA of 77 specimens) and morphologic (assessment of 129 specimens) evidence. Results indicate that the new form is sister species to N. amoenus and highly divergent genetically from all other species of Necromys (≥ 11.6% divergent). Similarly, the new species presents several unique morphological differences (in skin and skull characters) compared with all other species of the genus and is morphometrically distinct compared with 4 Argentine taxa. Finally, we assess the lectotype of Necromys conifer, discuss its morphologic similarities with other species of the genus, and argue for maintenance of the name Necromys. The description of this new species highlights, once again, the continuing need for collecting small mammals and conducting collections-based research.

Sexual segregation is common in polygynous mammals, particularly in wild ungulates, but is less known in bats of North America. Yet, the declining bat populations caused by white-nose syndrome, wind energy facilities, and habitat loss throughout eastern North America require habitat management, which may be sex specific. We thus determined sex-specific roosting and foraging habits of evening bats (Nycticeius humeralis) in north-central Arkansas. During the summers of 2013 and 2014, we equipped 70 individuals with radiotransmitters to track their foraging movements and identify their roosts that we characterized with 3 tree-level and 7 plot-level variables. We found that evening bat males and females segregate spatially with females foraging over a larger area than males. Females' roosts were also higher in elevation. Although the roost itself had similar characteristics between sexes, its surrounding habitat was characterized by less canopy cover and a smaller basal area for females. Our results support sex-specific habits and sexual segregation in a forest-dwelling bat, which highlights the importance of sex-specific studies to inform management decisions that would benefit both sexes, including females for which parental investment is higher.

Commerson's dolphin, Cephalorhynchus commersonii, is one of the smallest species of odontocete cetaceans. We aimed to study the postnatal cranial ontogeny of C. commersonii through geometric morphometric technique, analyzing the postnatal ontogeny of the symmetric and asymmetric components of shape and providing information about sexual dimorphism affecting cranial shape and size. We digitized 57 landmarks in a sample of 139 crania of an ontogenetic series. Our results indicate that C. commersonii presents sexual size dimorphism of cranium in adults, but not shape dimorphism. Major changes between juveniles and adults were associated with lengthening of the rostrum and accentuation of telescoping, as observed in other odontocetes. We found that the degree of asymmetry has a very subtle but still significant change during ontogeny, which may have functional implications. We also observed little general variation in skull shape during postnatal development, supporting the idea of the conservatism of young-like characters in adults of C. commersonii. In accordance with this, we detect a very early attainment of stability of shape and size, being statistically similar in males and females. Differences in overall cranial shape and growth patterns in C. commersonii and Pontoporia blainvillei can be functionally associated to specific modes of feeding, suggesting also differences in the melon morphology.

Reproduction is a critical fitness component in large herbivores. Biogeographic models predict that populations occurring at the edges of the range may have compromised reproductive rates because of inferior habitat at range peripheries. When reproductive rates are chronically low, ungulate populations may lack the resiliency to rebound quickly after periods of environmental stress, and this effect may be greatest for heat-sensitive organisms at their southern range limit. To assess the demographic vulnerability of moose (Alces alces), we studied relationships between reproductive rates, maternal age, and rump fat in the southernmost naturally occurring moose population in North America. For prime-aged moose in our study, pregnancy rates were high (92%), but moose aged < 3 or > 9 years had low pregnancy rates (32% and 38%, respectively). The relationship between rump fat and pregnancy was nonlinear such that a threshold of at least 2 mm of rump fat yielded a high probability of being pregnant midwinter. In contrast, among pregnant moose, the probability of both producing a calf and recruiting it until spring increased linearly with rump fat. We also conducted a meta-analysis of pregnancy and twinning rates for adult (≥ 2 years) moose across a latitudinal gradient to compare reproductive rates from our study to other populations in North America. Moose living at southern latitudes tended to have lower reproductive rates than those living in the core of moose range, implying that southern moose populations may be demographically more vulnerable than northern moose populations.

The measurement of stress hormone (glucocorticoid [GC]) concentration is increasingly used to assess the health of wildlife populations. However, for many species, we do not have a good understanding of the range of GC concentrations that might indicate a compromised individual. A temporary increase in GC concentration can prompt the adoption of behavior or activities to promote individual survival. However, chronic GC elevation results in deleterious effects on health that can reduce survival. In order to use GC concentration as a metric of individual fitness for a given species, it will be necessary to relate individual demographic rates to GC concentration. We related survival in American pikas (Ochotona princeps) to 2 different stress metrics, glucocorticoid metabolite (GCM) concentration in fecal samples and GC concentration in plasma samples. Annual survival was analyzed in relation to each of these stress metrics as well as other physiological metrics and habitat characteristics at several sites in the Rocky Mountains. Among the predictors considered, GCM concentration was by far the strongest predictor of annual survival in pikas, and individuals with higher baseline GCM were less likely to survive. Our metric of flea load was also negatively related to annual survival. Given the limited time and resources that characterize many wildlife conservation projects, it is important to establish which endocrine metrics are the most informative for a species. American pikas have been identified as a sentinel species for detecting effects of climate change, and several correlational studies have projected range contraction for the species. Our results suggest that more mechanistic projections might be possible given further study of the relationship between GCM and climate. Our approach contributes to a better understanding of factors affecting survival in this species and provides a basis for further research relating individual stress response and survival to environmental change.

The importance of weather in relation to food resources, in determining reproduction, remains poorly understood for mammals, particularly for species that do not depend on food resources limited by spring weather conditions. We studied the effects that weather and food supply had on timing of spring reproduction and observed litter size in 2 squirrel species, the Siberian flying squirrel and the European red squirrel, using long-term data sets spanning 20–30 years. Both species subsist on foods from tree masting, and these are available for squirrels from autumn until early spring. Good food conditions in winter and spring before reproduction had positive effects on spring reproduction in both species by advancing the onset of reproduction, and in flying squirrels, slightly increasing litter size. Higher temperature in late winter and, surprisingly, increased precipitation in late winter resulted in early reproduction in flying squirrels and red squirrels, respectively. In addition, higher early spring temperature was positively related to litter size in red squirrels, likely reflecting low survival of small juveniles in cold weather. Our study supports the view that spring reproduction in these species is determined by food supply before breeding. Our results also highlight the fact that reproduction is also dependent on weather.

The causes and consequences of physiological stress in wildlife are of great interest in a wide range of biological disciplines including understanding how environmental changes affect species fate and persistence. In some areas, the Eurasian red squirrel (Sciurus vulgaris) faces local extinction because of the invasive Eastern gray squirrel (Sciurus carolinensis). Whether or not physiological stress is induced by the presence of invasive species or contributes to local declines in Eurasian red squirrels is unknown. Here, we develop an assay that can be used to quantify physiological stress in fecal samples from Eurasian red squirrels to eventually address these questions. We captured free-living squirrels (6 females, 11 males) and placed them into captivity for 48 h. Fecal glucocorticoid metabolite (FGM) concentrations in female and male squirrels were significantly higher 24 and 32 h after initial captivity with a lag time to peak excretion ranging from 24 to 36 h. We measured FGM concentrations in free-living squirrels (37 females, 45 males) over a 3-year period. Lactating free-living squirrels had higher FGM concentrations compared to nonbreeding or pregnant squirrels but there were no differences in FGM concentrations in males with scrotal and abdominal testes. Free-living squirrels had the highest FGM concentrations in the winter and lowest in the summer (winter > autumn > summer). Squirrels kept in captivity for 4–48 h had significantly higher FGM concentrations than free-living squirrels (111 fecal samples from 82 squirrels). FGM concentrations in captive but not wild squirrels were significantly repeatable. We found no sex differences and no association with body mass in FGM concentrations in captive or free-living squirrels. Our results indicate that this assay can accurately quantify physiological stress in Eurasian red squirrels, which may be useful for future studies to document how the invasive Eastern gray squirrel contributes to local extinction.

Pumas (Puma concolor) are the primary predator of adult mule deer (Odocoileus hemionus) throughout most of arid New Mexico, and predation by pumas is popularly believed to limit mule deer populations. Predation can limit population size of prey if it is primarily additive or acts in addition to other mortality factors. Thus, clarifying the impact of predation is important because of misconceptions regarding the act of predation (i.e., killing an individual) rather than the effect (i.e., effects on population demography) cloud discussions of the issue. Herein, we tested the population-level question of whether puma predation on adult female mule deer is compensatory or additive mortality in multiple mule deer populations in New Mexico. We modeled annual survival rate as a function of cause-specific mortality rate. For this conservative test, a slope = 0 indicated complete compensation, whereas a slope = –1 indicated complete additivity. For all populations, the corrected slope of predation ultimately attributable to pumas was 0.00, ultimate and proximate puma predation combined was 0.10, ultimate puma predation and unknown causes of mortality combined was –0.28, and ultimate and proximate puma predation and unknown deaths combined was –0.23. Thus, puma predation appeared primarily compensatory. Despite small sample sizes, individual populations showed similar patterns indicating the compensatory nature of puma predation. Primarily compensatory predation for mule deer reflected the relatively low condition of deer. Survival was most strongly tied to individual condition in these populations, and a priori condition of puma-predated mule deer was lower than the population means. Compensatory mortality requires predisposition whether caused by decreased condition, high population density, or other factors. If conditions that predispose individual deer to mortality are present, managers should not assume that predation is limiting, regardless of predation rates.

Many herbivores exhibit phenotypic variations of their digestive system in response to changes in quality of food resources. This digestive plasticity is considered an adaptive trait for individuals to help them cope with variation in food resources and to fulfill nutritional needs. We investigated whether digestive phenotypic variations could contribute to sustain the population of introduced white-tailed deer (Odocoileus virginianus) on Anticosti Island (Québec, Canada) facing a winter diet of low-quality forage. We compared digestive morphology and in vitro digestibility of winter forage to that of deer from the original mainland population. Deer on Anticosti Island had a higher ruminal volume and digesta load (43% and 62%, respectively), greater absorption surface of the ruminal papillae, and greater relative mass of all forestomachs than deer from the mainland. Woody forage digestibility was similar between the 2 populations, even though faster kinetic digestion may occur for deer on Anticosti Island. Digestive plasticity appears to play a central role in sustaining high deer densities facing harsh forage conditions on Anticosti Island. Comparisons of digestive morphology and digestibility between populations that have access to forage of variable quality contribute to our understanding of the digestive response and the role of digestive plasticity for individuals facing a decline in diet quality.

Urbanization alters landscapes and ecosystem processes that result in negative impacts for many species. However, urbanization also creates novel environments that certain species, including carnivores, are able to exploit. Coyotes (Canis latrans) are 1 example of a species capable of exploiting urban environments throughout North America and, in some cases, becoming involved in human–coyote conflict. As part of a comprehensive study of human–coyote coexistence in the Denver metropolitan area of Colorado, we investigated the spatial ecology of coyotes to determine movement and activity patterns relative to the urban matrix. We examined home-range size, habitat use, and resource selection for 22 coyotes monitored with GPS collars during 2012–2014. Mean (± SD) home-range size of resident coyotes (11.6 ± 11.0 km²) was smaller than ranges of transient coyotes (200.7 ± 232.4 km²). Home-range size did not vary by season or sex, but resident coyotes during the day (7.2 ± 10.5 km²) had smaller home ranges than during the night (11.3 ± 10.8 km²). Coyotes had high percentages of developed lands (44.5 ± 18.9%) within their home ranges, contrary to previous studies of urban coyotes. However, the percentage of coyote locations in natural lands (48.9 ± 22.4%) was higher than in developed lands (20.6 ± 11.7%). Homerange size of residents was not related to either the percentage of developed lands or altered lands within home ranges. Coyotes selected natural lands over developed lands, and they increased activity at night. Although coyotes were able to thrive in home ranges containing large amounts of development, they continued to avoid areas with high human activity by primarily residing in areas with natural land cover. Similar to urban areas throughout the Northern Hemisphere, coyotes in the Denver metropolitan area have become efficiently adapted to a highly developed landscape, reflecting the flexible nature of this opportunistic carnivore.

Nurturant behavior toward dead conspecifics has been documented in several free-ranging marine and terrestrial mammals but still remains undocumented and poorly understood for most species. This study describes observations of adults carrying dead calves and juveniles in 7 odontocetes (toothed cetaceans) species and discusses the subject in mammals in general. Observations are based on 14 events from 3 oceans and constitute the 1st records for Indo-Pacific bottlenose dolphins (Tursiops aduncus), spinner dolphins (Stenella longirostris), killer whales (Orcinus orca), Australian humpback dolphins (Sousa sahulensis), and sperm whales (Physeter macrocephalus), as well as presenting additional records for Risso's dolphins (Grampus griseus) and shortfinned pilot whales (Globicephala macrorhynchus). Information on how the adults supported and carried the dead conspecifics, on the gender of both adults and dead young, and on the age class of the dead young, is presented. Moreover, a comparison with terrestrial mammals, including a compilation of published literature, and a discussion on possible hypotheses to explain this particular type of behavior are given. The present study helps to corroborate that adults mourning their dead young is a common and globally widespread behavior in long-lived and highly sociable/cohesive species of mammals.

We report the long-distance dispersal of a subadult male cougar (Puma concolor) from South Dakota to Milford, Connecticut, where it was struck and killed by a vehicle. Genetic samples suggest this animal originated from the Black Hills of South Dakota while isotope analysis and physical inspection revealed no evidence that the animal had been held in captivity. We detected this dispersing individual at 5 locations along its route (Minnesota, 3 times in Wisconsin and New York) with DNA from fecal or hair samples, and with multiple photographs from citizenrun camera traps (3 in Wisconsin and 1 in Michigan). The > 2,450 km straight-line distance (Black Hills of South Dakota to Connecticut) traveled by the cougar is the longest dispersal documented for the species. We propose a likely route of > 2,700 km over 2 years based on topography and our confirmed records. We suggest that this excessive movement was motivated by the absence of female cougars along the route. The documentation of such a rare biological event not only shows the great dispersal potential for male cougars but also highlights our ability to detect these movements with verifiable voucher DNA and photographic records. Evidence collected for this one animal, and complete absence of verifiable data from most anecdotal reports of cougars in the east, further confirms the lack of a breeding population in the region.

Mate choice based on age and body size is poorly understood among cervids. We used 14 microsatellite DNA loci to assign parentage and reconstruct the pedigree of a captive population of white-tailed deer (Odocoileus virginianus) in order to evaluate their mate choice and reproductive success. From 2008 to 2013, we assigned both dam and sire to 87 litters. Age differences between mated pairs did not differ from random pairings and we found no apparent relationship of skeletal size between pairs. Our results highlight the plasticity of mating success for white-tailed deer and we speculate their mating system has evolved to maximize fertility. Our investigation was the first to explore mated pairs of white-tailed deer with such a high proportion of candidate parents sampled and the first to incorporate vaginal implant transmitters to validate genetic sampling techniques. This knowledge could help local and regional wildlife managers comprehend the unpredictability of mating success of whitetailed deer.

Urban areas are highly dynamic landscapes and urbanization patterns are spatially complex. For effective wildlife management in urban landscapes, it is essential to consider the complex history of urbanization and its timedelayed effects on species distribution. We examined whether the history of local land use affects the time-delayed response of Japanese hares (Lepus brachyurus) to landscape change in an urban ecosystem by hierarchically reducing the factors affecting differences in the response. We evaluated the occurrence of hares in 62 forest patches along an urban gradient in the Tama Hills area, Japan. Using sites where the surrounding landscape remained relatively stable, we calculated the habitat threshold of hare occurrence based on the surrounding forest area. We extracted sites that used to be suitable for hare occurrence in the past but later on surpassed the identified habitat threshold (i.e., ‘regressive sites’) and analyzed the landscape factors explaining the extinction debt of hares. Finally, we mapped potential extinction debt throughout the study region. We detected possible extinction debt in 4 regressive sites. We also found that forest patch size and the number of surrounding forest patches were related to hare occurrence. Based on this prediction, several other sites with potential extinction debt were identified in the study region. We found that the delayed response of the Japanese hares is likely caused by differences in forest fragmentation processes at each site. Our hierarchical approach could be an effective methodology for detecting and explaining the cause of extinction debt at the local scale and would contribute to the management of urban land for wildlife conservation.

Live-capture of animals is a widely used technique in ecological research, and previously trapped individuals often respond to traps with either attraction or avoidance. The effects of trapping on animals' risk perception are not often studied, although nonlethal effects of risk can significantly influence animals' behavior and distribution. We used a combination of experimental (giving-up densities: GUDs) and behavioral (vigilance rates) measures to gauge monkeys' perceived risk before and after a short livetrapping period aimed at ear-tagging monkeys for individual recognition as part of ongoing research. Two groups of arboreal samango monkeys, Cercopithecus albogularis schwarzi, showed aversion to capture in the form of generalized, group-level trap shyness after 2 individuals per group were cage trapped. We predicted that trapping would increase monkeys' antipredatory behavior in trap vicinity and raise their GUDs and vigilance rates. However, live-capture led to no perceptible changes in monkeys' use of space, vigilance, or exploitation of experimental food patches. Height above ground and experience with the experiment were the strongest predictors of monkeys' GUDs. By the end of the experiment, monkeys were depleting patches to low levels at ground and tree heights despite the trapping perturbation, whereas vigilance rates remained constant. The presence of cage traps, reintroduced in the final 10 days of the experiment, likewise had no detectable influence on monkeys' perceived risk. Our findings, consistent for both groups, are relevant for research that uses periodic live-capture to mark individuals subject to long-term study and more generally to investigations of animals' responses to human interventions.

Sigmodontinae is a very rich clade of rodents that is widespread throughout the Neotropics. The arboreal mice Juliomys comprise a poorly known branch, with incomplete information about species richness, phylogenetic position, and geographic distribution. Based on a sample from the Atlantic Forest of Southern Brazil, we name and describe a new species for the genus. This new species can be distinguished from others in the genus by its karyotype, morphological traits, and cytochrome b (Cytb) gene sequence. It has a unique karyotype (2n = 32, FN = 48), and forms a well-supported monophyletic haplogroup, which is phylogenetically distant from the remaining species of Juliomys. The genetic differentiation ranges from 11.1% to 19.7%, and there are 24 molecular autopomorphies in the Cytb gene. The new species can be distinguished from J. pictipes by morphological and morphometric analyses. However, we consider the new species as cryptic, not easily recognized by morphological characteristics of other species of Juliomys. This taxon seems to be endemic to the Brazilian Araucaria Forest in the Atlantic Forest biome, occurring in sympatry with its congeneric species J. ossitenuis and J. pictipes. In this research, we describe a new species for the genus and extend species distributions in the Atlantic Forest.