Rodents play a key role in forest regeneration by dispersing seeds and interspecific differences in seed preferences could have important consequences for forest growth. The White-footed Mouse (Peromyscus leucopus) and Deer Mouse (Peromyscus maniculatus gracilis) are 2 closely related species that can exploit Red Oak (Quercus rubra) acorns but may display different preference levels due to the high tannin concentration present in these acorns. Here we investigated how White-footed Mice and Deer Mice differ in their ability to exploit Red Oak acorns. We conducted a cafeteria-style experiment where we offered mice (n = 61) acorns of Red Oak and Bur Oak (Q. macrocarpa; control seed with lower tannin levels) and video-recorded their preference and the acorn fate (consumed or cached). Using mixed-effects models, we found that both mouse species selected and consumed Bur Oak acorns at a high rate; however, White-footed Mice were 6.67 times more likely to select and consume Red Oak acorns than Deer Mice. Furthermore, White-footed Mice tended to cache Red Oak acorns near the surface where there is a higher chance of germination, while they usually consumed Bur Oak acorns. Our results suggest that Red Oaks have a better strategy for avoiding predation than Bur Oaks (i.e., high tannin levels leading to caching), and the strong interaction between the White-footed Mouse and Red Oak might be an important mechanism behind the current range expansion of both species in response to climate change.

In multi-carnivore systems individuals must forage and reproduce while also competing with other carnivores and avoiding intraguild predation. These interactions may vary by strength and scales across different ecosystems. We used occupancy analyses and attraction–avoidance indices to assess large- and fine-scale interactions, respectively, between Cougars (Puma concolor), Bobcats (Lynx rufus), and Coyotes (Canis latrans) in northeast Oregon based on data from camera traps set during the summer and fall of 2016 and 2017. To determine the importance of habitat preferences and spatial overlap, we compared occupancy (probability of use) models that included habitat covariates with and without species co-occurrence terms. Detection was different for all species and was influenced by roads, game trails, and canopy cover. Terrain ruggedness was important for all species; Bobcats showed the strongest preference for ruggedness, Cougars showed a weak preference, and Coyotes significantly but weakly avoided rugged areas. The top probability of use model showed that Bobcats and Coyotes were 1.88 times more likely to spatially overlap on roads. We also found evidence that interactions among carnivores were scale-dependent. At larger scales, habitat preference was more important than interactions with other carnivores, whereas at finer scales, most carnivores avoided each other. At fine spatiotemporal scales, our attraction–avoidance analyses showed that Bobcats avoided Coyotes and Coyotes avoided both Bobcats and Cougars. These findings suggest that carnivores in our study system were adept at minimizing conflict through fine-scale avoidance in space and time, that the human footprint can influence carnivore interactions, and that studying carnivore interactions at multiple scales is important for understanding the effects of spatial overlap and potential competition.

Species distribution and activity patterns vary across regions, and these patterns reveal key information about the biology of a given species. However, such data in Niubeiliang National Nature Reserve located in the Qinling Mountains, Shaanxi Province, China, are inadequate due to limited monitoring studies. From September 2017 to December 2019, 57 infrared cameras were installed to monitor species distribution relative to distance from National Highway 210, and spatial and temporal activity patterns in Niubeiliang National Nature Reserve (elevation range 1,100 to 2,802 m). Sixteen species of mammals were recorded in our survey. The 4 most frequently detected species were Reeves's Muntjac (Muntiacus reevesi), Wild Boar (Sus scrofa), Pere David's Rock Squirrel (Sciurotamias davidianus), and Golden Takin (Budorcas taxicolor bedfordi). Daily patterns of these species indicated that Reeves's muntjacs and golden takins were more active at dawn and dusk, whereas wild boars and Pere David's rock squirrels were more active during the day. The relative abundance index of these mammals varied seasonally. Wild boars and Pere David's rock squirrels showed no obvious preference in elevation distribution, Reeves's muntjacs preferred low-elevation habitats (1,300 to 1,600 m), and golden takins mainly inhabited high-elevation areas (1,900 to 2,100 m). Golden takins showed obvious avoidance of roads, with avoidance distance from the road of >300 m. In contrast, Reeves's muntjacs were remarkably abundant within 200 m of the road. For both wild boars and Pere David's rock squirrels, there was no significant difference in RAI among 5 highway ranges. These findings help describe the distribution and activity patterns of these species in Qinling, to monitor their population dynamics, and to develop tailored conservation strategies for the 4 species and sympatric wildlife.

物种分布和活动规律在不同地区有所不同，这些规律能够揭示物种关键的生物学信息。然而，关于陕西秦岭牛背梁国家自然保护区物种分布和活动规律的研究还较少。2017年9月至2019年12月，在陕西牛背梁国家自然保护区，利用 57台红外相机监测物种空间分布、活动节律及210国道对物种的影响情况。结果显示，保护区内共监测到了16种哺乳动物，其中小麂(Muntiacus reevesi)、野猪(Sus scrofa)、岩松鼠(Sciurotamias davidianus)和羚牛(Budorcas taxicolor bedfordi)是相对多度指数(relative abundance index, RAI) 排前4的物种。对这4个物种进行时空活动规律分析表明，小麂和羚牛具明显的晨昏活动习性，而野猪和岩松鼠主要以白天活动为主，并且这4种哺乳动物随着季节变化表现出不同的活动规律。野猪和岩松鼠在海拔分布上没有明显的偏好，小麂在低海拔地区(1300 ∼ 1600 m)活动频繁，而羚牛主要在高海拔地区(1900 ∼ 2100 m)活动。道路影响情况研究显示，羚牛在距离道路300 m以外的范围活动显著增加，表现出明显的回避效应，相反小麂在距离道路200 m以内活动频繁。野猪和岩松鼠在5个公路范围内活动强度均无显著差异。本研究结果有助于了解这4个物种的种群动态变化并为制定有针对性的保护策略提供数据基础。

Interactions among predators can have cascading impacts on communities and ecosystems. These interactions often occur around carrion, where the carrion provides a food reward, but also a risk of encountering other, potentially dominant, predators. Understanding how predators balance risk and reward at carrion, and how perceived risk changes in response to carcass origins and conditions, provides valuable insight into intraguild interactions. We investigated Coyote (Canis latrans) behavior at carrion simulated as cache sites treated with Cougar (Puma concolor) scent versus carrion used as control sites to better understand how Coyotes assess risk while feeding on carrion. Coyotes displayed similar behavior between sites treated and untreated with Cougar scent, suggesting that the presence of Cougar scent did not alter perceived risk by Coyotes in our study. Instead, Coyote behavior responded to carcass age, elevation, and whether avian scavengers had visited the carcass. Coyotes spent more time feeding, more time on camera, and touched carcasses quicker as carcass age increased. Avian scavengers appeared to compete with Coyotes, and while the presence of avian scavengers reduced time to carcass detection by Coyotes, it also decreased time spent feeding. These results suggest that carcass condition is a more important indicator of risk and reward than the presence of dominant predator scent to Coyotes. Predator scent may be an unreliable cue of immediate predator presence. Alternatively, all carcasses may be risky because dominant predators also scavenge carrion, creating similar risk regardless of previous visitation by dominant predators. These results provide insights into predator interactions and can also inform the use of scent cues in wildlife management.

Las interacciones entre depredadores pueden tener impactos en cascada en las comunidades y los ecosistemas. Estas interacciones entre las especies a menudo ocurren alrededor de la carroña, donde la carroña representa un alimento recompensa, pero también es un riesgo de encontrar otros predadores potencialmente dominantes. Entender cómo los depredadores equilibran el riesgo y la recompensa, y cómo el riesgo percibido cambia en respuesta de las condiciones. El orígenes de los cadáveres suministra información valiosa sobre las interacciones dentro del gremio. Investigamos el comportamiento del coyote (Canis latrans) en condiciones de carroña simulada en sitios tratados con el aroma de puma (Puma concolor) contra sitios de control con carroña para comprender mejor cómo los coyotes evalúan el riesgo mientras se alimentan. Los coyotes mostraron comportamientos similares entre los sitios tratados y no tratados con el olor de puma, sugiriendo que la presencia del olor de puma no alteró el riesgo percibido de los coyotes en nuestro estudio. En cambio, el comportamiento de los coyotes respondió a la edad del cadáver y si las aves carroñeras habían visitado el cadáver. Los coyotes pasaron más tiempo alimentándose, frente de la cámara y hurgaron los cadáveres más rápido a medida que aumentaba el tiempo de exposición del cadáver. Las aves carroñeras parecen competir con los coyotes. La reducción de la presencia de aves carroñeras se manifestó en la disminución del tiempo dedicado a alimentarse por los coyotes. Estos resultados sugieren que la condición del cadáver es el indicador más importante de riesgo y recompensa, que la presencia del olor del puma a los coyotes. El olor de un depredador puede ser una señal poco confiable de la presencia inmediata de un predador. Alternativamente, todos los cadáveres pueden ser riesgosos debido a que los depredadores dominantes también hurgan la carroña, creando un riesgo similar en cualquier caso, incluso si existieron visitas previas de los depredadores dominantes. Estos resultados proporcionan información sobre las interacciones de los depredadores y también informan del uso de señales olfativas en el manejo de la vida silvestre.

Old-growth forests harbor a large amount of complex structural features that result in a wide array of wildlife habitats. However, intensive forest management is gradually converting old-growth forest into younger, even-aged stands, reducing structural complexity and threatening the persistence of old-growth-dependent species. Maintaining elements of complex stand structure is critical to the conservation of old-growth forest specialists that use different habitat components at different periods of their annual cycle, and it requires a comprehensive understanding of seasonal variation in the habitat needs of these species. However, difficulties in observing free-ranging animals have sometimes limited our ability to assess such variations in habitat requirements, especially for small, elusive species. To address this, we used GPS telemetry collars to describe fine-scale habitat selection patterns of 6 male American Martens (Martes americana) during 2 contrasting periods of the year (snow-free, from mid-April to mid-November; snow-covered, from mid-November to mid-April), an objective formerly hard to achieve using conventional VHF telemetry. We used resource selection functions conducted at the fourth order of selection to compare habitat characteristics found at the sites used by martens (GPS locations, n = 100) to those found on an equal number of available sites (random points, n = 100) within each individual seasonal home range. We conducted vegetation surveys on these 200 sites to describe habitat and built candidate models representing different concurrent hypotheses. Our results showed that proxies of prey availability, predator avoidance, and thermal constraints were the primary factors influencing marten habitat selection during both periods, although their respective importance differed between periods. Martens selected sites with a high density of large-diameter snags (≥30·ha^–1), high conifer canopy closure (≥53%), and a dense lateral cover (≥81%) during the snow-free period, but selected sites with a high volume of coarse woody debris (≥64 m³·ha^–1) and high conifer canopy closure (≥48%) during the snow-covered period. Our results highlight the importance of contrasting seasonal changes in habitat selection patterns of small carnivores and may help maintain structural attributes in the landscape that are suitable for male American Martens.

Ecosystem engineers modify their environment and influence the availability of resources for other organisms. Burrowing species, a subset of allogenic engineers, are gaining recognition as ecological facilitators. Burrows created by these species provide habitat for a diverse array of other organisms. Following disturbances, burrows could also serve as ecological refuges, thereby enhancing ecological resistance to disturbance events. We explored the ecological role of Common Wombat (Vombatus ursinus) burrows using camera traps in forests of southeastern Australia. We compared animal activity at paired sites with and without burrows, from the same fire severity class and habitat. We examined how animal activity at Common Wombat burrows was affected by the 2019–20 Black Summer bushfires in Australia. We predicted that burrows would serve as hotspots for animal activity and as refuges in burned areas. The activity of several species including Bush Rat (Rattus fuscipes), Agile Antechinus (Antechinus agilis), Lace Monitor (Varanus varius), Painted Button-quail (Turnix varius), and Grey Shrike-thrush (Colluricincla harmonica) increased at sites where Common Wombat burrows were present, while other species avoided burrows. Species that were more active at burrows tended to be smaller mammal and bird species that are vulnerable to predation, whereas species that avoided burrows tended to be larger mammals that might compete with Common Wombat for resources. Species composition differed between sites with and without burrows, and burrow sites had higher native mammal species richness. The association of several species with burrows persisted or strengthened in areas that burned during the 2019–20 Black Summer bushfires, suggesting that Common Wombat burrows may act as ecological refuges for animals following severe wildfire. Our findings have relevance for understanding how animals survive, persist, and recover following extreme wildfire events.

Habitat specialists have been largely overlooked in old-growth pinyon–juniper woodlands, despite specialists exhibiting heightened sensitivity to anthropogenic habitat loss. Furthermore, small mammal relationships within pinyon–juniper woodlands have most commonly been investigated via species abundance or habitat use, rather than habitat selection, thereby providing limited management metrics. We used the Oscura Mountains Colorado Chipmunk (Neotamias quadrivittatus oscuraensis) as a model organism to evaluate whether old-growth conditions drive resource selection by small mammals associated with pinyon–juniper woodlands. The goal of our study was to determine resources important to the chipmunk to inform management decisions. We evaluated microhabitat selection by testing a priori predictions based on natural history characteristics of the chipmunk and the woodlands. We grouped predictions into habitat characteristics affiliated with or not affiliated with old growth. We tested predictions under a multistage modeling framework using generalized linear mixed models with a binomial response variable of use versus availability. Probability of selection by chipmunks increased with increasing mean juniper diameter and increasing variation of pinyon diameter and decreased with increased distance to rocky escape terrain and increased mean percent grass cover. Our findings support the classification of the Oscura Mountains Colorado chipmunk as an old-growth pinyon–juniper specialist, as the chipmunk displayed disproportionate preference for old-growth microhabitat conditions. We recommend management policies that conserve old-growth multiage stands of pinyons and junipers. Old-growth conditions near outcroppings, escarpments, and large boulders are of particular conservation concern. Further, thinning resulting in increased grass cover may be detrimental to this old-growth pinyon–juniper specialist.

The genus Caenolestes is the most species-rich of the marsupial order Paucituberculata. Two species inhabit Colombia (and also occur in Ecuador) with a discontinuous distribution that has not been accounted for in previous studies—Caenolestes fuliginosus known from the Central and Eastern Andes, and C. convelatus restricted to the Western Andes. Here, we present new and noteworthy records of Caenolestes from the Western Andes at the distributional gap of C. convelatus, and outside the known range of C. fuliginosus. We present detailed comparisons using discrete and continuous diagnostic morphological characters, with type material and additional specimens collected nearby, to assess the identity of the new specimens. We performed statistical analyses at species and subspecies levels, and used a principal components analysis to explore the ordination of the new specimens in morphological space. We found that although these specimens are from the Western Andes, they present traits similar to C. fuliginosus and show great overlap with the morphospace of that species. The new records did not differ statistically with C. fuliginosus or any of its subspecies, but they differed in 20 craniodental measurements from C. convelatus. We also report differences at subspecies level within and between species. Based on these observations, we identified these records as C. fuliginosus, expanding its known distribution to the midportion of the Western Andes, across de Cauca valley. We discuss the biogeography of these 2 species in light of the new data and the context of high Andean habitats, especially regarding the contrasting biogeographical patterns found in other taxa in the Northern Andes. Finally, we discuss the need for a new and exhaustive review of the systematics and biogeography of the genus.

El género Caenolestes es el más diverso del orden de marsupiales Paucituberculata. Dos especies habitan en Colombia (y también en Ecuador) con una distribución discontinua que no ha sido explorada antes: Caenolestes fuliginosus conocido de los Andes Centrales y Orientales y C. convelatus restringido a los Andes Occidentales. Aquí, presentamos nuevos registros de Caenolestes de los Andes Occidentales en la brecha de distribución de C. convelatus y fuera del rango conocido de C. fuliginosus. Presentamos comparaciones detalladas utilizando caracteres morfológicos diagnósticos, tanto discretos como continuos, comparando con el material tipo y otros especímenes recolectados cerca para evaluar la identidad de los nuevos registros. Evaluamos las diferencias estadísticas a nivel de especie y subespecie, y realizamos un análisis de componentes principales para explorar la ordenación de los nuevos especímenes en el espacio morfológico. Encontramos que, aunque estos registros son de los Andes Occidentales, presentan rasgos similares a C. fuliginosus y muestran una gran superposición con el morfoespacio de esta especie. No encontramos diferencias estadísticas entre los nuevos registros y C. fuliginosus, ni con ninguna de sus subespecies. Sin embargo, estos registros difirieron en 20 medidas cráneodentarias de C. convelatus. Además, reportamos diferencias entre especies y subespecies de estos dos taxones. Con base en estas observaciones, estos registros son identificados como C. fuliginosus, ampliando su distribución a la parte media de los Andes Occidentales, a través del valle del Cauca. Discutimos la biogeografía de estas 2 especies a la luz de los nuevos datos y el contexto de los hábitats altoandinos, especialmente con respecto a los patrones biogeográficos contrastantes que se encuentran en otros taxones en los Andes del Norte. Finalmente, discutimos la necesidad de una revisión exhaustiva de la sistemática y biogeografía del género.

The distribution pattern of a taxon is a consequence of historical and contemporary processes—specifically ecological and evolutionary processes—which tend to result in distributional congruence among species that respond similarly to the same processes. This congruence leads to the establishment of areas of endemism that are important for delimiting biogeographic regions. In the Neotropical region, different definitions of area of endemism have been proposed based on the distributional patterns of mammal species, each according to different methods and assumptions. In this study, we aimed to identify areas of endemism of Neotropical mammals, represented by 361 species of Placentalia (Xenarthra, Chiroptera, and Carnivora) and Marsupialia (Didelphimorphia and Paucituberculata), using an endemicity analysis implemented by the software NDM (eNDeMism software) and a hierarchical cluster analysis based on Simpson's beta dissimilarity metric (βsim). The results suggest alternative spatial configurations within northern and southern parts of the Neotropics along transition zones. Additionally, there are indications of more restricted areas of endemism throughout the Neotropical region and with more species supporting the areas, such 1 area located in the region corresponding to the Atlantic forest and 2 areas corresponding to Mexican transition zone. The study enhances our understanding of Neotropical mammal biogeography and underscores the importance of using primary distribution data. Previous studies found 82 endemic species based on range maps, whereas our analyses identified 172 endemic species, including 125 that are newly proposed as such, and also confirmed the existence of 47 previously reported endemic species.

O padrão de distribuição de um táxon é consequência de processos históricos e contemporâneos, ecológico-evolutivos, havendo tendencialmente congruência distribucional entre espécies que respondem de forma semelhante aos mesmos processos. Esta congruência é responsável pela fixação de áreas de endemismo, as quais são de suma importância para a delimitação de regiões biogeográficas. Para a região Neotropical existem diferentes definições de área de endemismo associadas a padrões de distribuição de espécies de mamíferos, cada qual de acordo com distintos métodos e pressupostos. Este estudo teve como objetivo identificar áreas de endemismo de mamíferos neotropicais, representados por 361 espécies dos taxa Placentalia (Xenarthra, Chiroptera e Carnivora) e Marsupialia (Didelphimorphia e Paucituberculata), a partir da análise de endemicidade (NDM) e propor uma regionalização com base em uma análise hierárquica de cluster com o emprego de métrica de dissimilaridade Simpson's beta (βsim). Os resultados do estudo sobre endemismo e regionalização sugerem configurações espaciais alternativas nas extensões norte e sul do Neotrópico ao longo de zonas de transição. Além disso, há indícios de áreas de endemismo mais restritas em toda a região Neotropical e com mais espécies apoiando as áreas, como uma área localizada na região correspondente à Mata Atlântica e duas áreas correspondentes à zona de transição Mexicana. O estudo aumenta nossa compreensão da biogeografia dos mamíferos neotropicais e ressalta a importância do uso de dados de distribuição primária. Destacamos que estudos anteriores encontraram 82 espécies endêmicas com base em mapas de distribuição, nossas análises identificaram 172 espécies endêmicas, incluindo 125 novas, e também confirmaram a existência de 47 espécies relatadas anteriormente.

Flattened and flexible spiny hairs, the aristiforms, evolved independently in some lineages of rodents, but unlikely capable of causing severe damage to predators. Their biological roles are not yet clearly known and some different thermoregulatory functions have been proposed, often associated with severe climatic conditions but not yet tested. In this study we investigated whether climate may be a major factor shaping geographic variation of length and width of aristiform hairs of 2 species of Neotropical spiny rats of the genus Trinomys (Echimyidae) occurring in eastern Brazil: T. albispinus and T. setosus. Results revealed clinal variation in these hairs. While bioclimatic factors and geographic distance together accounted for up to a third of the morphometric variation, the exclusive impact of climate was limited, explaining only up to 3% of the observed variation. However, considering the close association between climate and geographic distance, the role of climate in shaping aristiform hair cannot be discounted. While our results did not fully support the hypothesis that well-developed, wide spiny hairs are selected for greater protection against rain for underhairs, they marginally supported their role in facilitating heat loss in warm environments by facilitating water condensation. More consistently, results show that narrow spiny hairs tended to evolve in cold environments, likely enhancing thermal insulation. The length of aristiform hair in T. albispinus also appeared to respond to this function, becoming longer in cold and high-altitude regions. However, we cannot rule out the possibility of an evolutionary response correlated with selection on underhairs. Future experimental studies should test the thermoregulatory function of flexible spiny hairs and investigate the geographic variation of these structures in other rodent species.

Pelos espinhosos achatados e flexíveis, conhecidos como aristiformes, evoluíram independentemente em algumas linhagens de roedores. Sendo pouco provável que sejam capazes de causar danos graves aos predadores, seus papéis biológicos ainda não são claramente conhecidos. Algumas funções termorreguladoras diferentes foram propostas para eles, frequentemente associadas a condições climáticas severas, mas ainda não testadas. Neste estudo, investigamos se o clima pode ser um fator crucial influenciando a variação geográfica no comprimento e na largura dos pelos aristiformes de 2 espécies de ratos-de-espinho neotropicais do gênero Trinomys, que ocorrem no leste do Brasil: T. albispinus e T. setosus. Os resultados revelaram variação clinal nesses pelos. Enquanto fatores bioclimáticos e a distância geográfica juntos explicaram até um terço da variação morfométrica, o impacto exclusivo do clima foi limitado, explicando apenas até 3% da variação observada. Ainda assim, considerando a estreita associação entre o clima e a distância geográfica, a influência do clima sobre a morfologia dos pelos aristiformes não pode ser descartada. Embora nossos resultados não tenham apoiado completamente a hipótese de que pelos espinhosos largos e bem desenvolvidos sejam selecionados para maior proteção contra chuva para os subpelos, eles apoiaram marginalmente seu papel na facilitação da perda de calor em ambientes quentes, ao favorecer a condensação da água. De forma mais consistente, os resultados mostram que pelos espinhosos estreitos tendem a evoluir em ambientes frios, provavelmente melhorando o isolamento térmico. O comprimento do pelo aristiforme em T. albispinus também parece responder a essa função, tornando-se mais longo em regiões frias e de alta altitude. Contudo, não podemos descartar a possibilidade de uma resposta evolutiva correlacionada à seleção dos subpelos. Estudos experimentais futuros que testem a função termorreguladora dos pelos espinhosos flexíveis e investiguem a variação geográfica destas estruturas em outras espécies de roedores são necessários para esclarecer essas questões.

Although Mexico holds the southernmost hibernating bats in North America, information on winter behavior and hibernacula microclimate use of temperate Mexican bats is limited. We studied hibernating bats at high altitudes (>1,000 m a.s.l.) in northern and central Mexico during 5 consecutive winters. Our aims were to document and describe the hibernacula, winter behavior (such as abundance and roost pattern), and microclimates (estimated as adjacent substrate temperature) of cave-hibernating bats in Mexico. We found 78 hibernacula and 6,089 torpid bats of 10 vespertilionid species, increasing by over 50% the number of cave-hibernating bat species and quadrupling the number of hibernacula for Mexico. Hibernacula were at altitudes between 1,049 and 3,633 m a.s.l., located in 3 mountain ranges, mainly in oak and conifer forests. Myotis velifer was the most common species, followed by Corynorhinus townsendii and C. mexicanus. We recorded the adjacent substrate temperatures from 9 species totaling 1,106 torpid bats and found differences in microclimate use among the 3 most common species. In general, abundance of torpid bats in our region of study was similar to those in the western United States, with aggregations of tens to a few hundred individuals per cave, and was lower than in the eastern United States where a cave may hold thousands of individuals. Knowledge of bat hibernation is crucial for developing conservation and management strategies on current conditions while accommodating environmental changes and other threats such as emerging diseases.

Aunque México tiene los murciélagos hibernantes más sureños en Norteamérica, la información sobre el comportamiento invernal y el uso de microclimas en los refugios de hibernación de los murciélagos templados mexicanos es limitada. Estudiamos a los murciélagos hibernantes en altitudes altas (>1000 msnm) en el norte y centro de México durante cinco inviernos consecutivos. Nuestros objetivos fueron documentar y describir las cuevas de hibernación, el comportamiento invernal (como la abundancia y patrón de percha), y el uso de microclimas (estimado como la temperatura del sustrato adyacente), de los murciélagos que hibernan en cuevas en México. Encontramos 78 cuevas de hibernación con 6089 murciélagos en torpor de 10 especies de vespertiliónidos, incrementando en más del 50% el número de especies de murciélagos que hibernan en cuevas y cuadriplicando el número de cuevas de hibernación para México. Las cuevas de hibernación estuvieron en elevaciones entre 1049 y 3633 msnm, localizadas en tres cadenas montañosas, principalmente en bosques de encinos y coníferas. Myotis velifer fue la especie más común, seguida por Corynorhinus townsendii y C. mexicanus. Reportamos las temperaturas del sustrato adyacente de 1106 murciélagos en torpor de nueve especies y encontramos diferencias en el uso de microclimas entre las tres especies más comunes. Aquí proveemos información relevante para especies de murciélagos templados en la ocurrencia más sureña de hibernación de murciélagos en Norteamérica. En general, la abundancia de murciélagos en torpor que encontramos fue similar a las del oeste de Estados Unidos, con agregaciones de decenas y algunos cientos de individuos por cueva; y fue menor que las del este de Estados Unidos, donde las cuevas pueden albergar miles de murciélagos. El conocimiento de la hibernación de murciélagos es crucial para el desarrollo de estrategias de conservación y manejo adecuadas en la actualidad y mientras se adaptan a los cambios ambientales y a otras amenazas tales como las enfermedades emergentes.

Arthropod–bat interactions are often considered as a base model for studying factors underlying predator–prey coevolutionary processes. Bats developed ultrasonic echolocation to hunt, and in response some arthropods developed defense mechanisms such as ultrasonic hearing, allowing them to elude bat predators. The present study analyzes the feeding patterns of bats, focusing on sonic-auditory sensory mechanisms in predator–prey interactions. Next-generation DNA sequence data from fecal samples were used to analyze the diet of 17 bat species from Mexico. Arthropod prey taxa were classified according to their auditory traits, and echolocation data were recompiled from literature review. We: (i) classified arthropod families according to their hearing ability; (ii) estimated arthropod taxon richness and proportion in the diet of each bat species; and (iii) used multidimensional scaling, principal component analysis, and regression to analyze prey consumption patterns in relation to their auditory traits and in relation to echolocation characteristics of bats. Finally, we analyzed the relationship between foraging time and auditory characteristics of prey. Families with hearing organs correspond to the orders Lepidoptera and Orthoptera. We registered 20 families of Lepidoptera and 5 of Orthoptera—7 and 3 with hearing organs, respectively. Of these orders, families lacking ears were recorded in the diet of a few bat species. Our results support the allotonic frequency hypothesis predicting a difference in emission frequency intervals between predator and prey. However, we found that the consumption of earless moths is less frequent and is related to diurnal and twilight activity—hence, their consumption is limited to bat species foraging early. Results indicate bats feed on arthropod prey successfully despite the ultrasonic hearing ability of the prey. These results may be due to counteradaptations that allow maintenance of an asymmetric “arms race” between bats and eared insects that favors the predator.

La interacción artrópodo-murciélago es considerado un modelo base para estudiar diversos factores subyacentes a los procesos coevolutivos entre depredador-presa. Los murciélagos han desarrollado y perfeccionado la ecolocación ultrasónica para poder cazar a sus presas, en respuesta algunos artrópodos han desarrollado la audición a esos sonidos para tener una respuesta elusiva a los murciélagos depredadores. En el presente trabajo exploramos los patrones de dieta de los murciélagos, enfocado en la interacción sónica-auditiva entre depredador-presa. Se emplearon datos de secuenciación de ADN de Nueva-generación de excretas de 17 especies de murciélagos de diferentes localidades de México y se recopilaron datos de las características de sus llamados de ecolocación a partir de revisión bibliográfica. Nosotros: (i) clasificamos a las familias de artrópodos de acuerdo sus rasgos de capacidad auditiva; (ii) estimamos la riqueza de taxones y su proporción en la dieta de cada especie de murciélago, y (iii) empleamos análisis de escalamiento multidimensional, análisis de componentes principales y regresión para analizar los patrones de consumo de las presas en relación con sus rasgos auditivos y en relación con las características de ecolocación de los murciélagos. Finalmente analizamos la relación entre la hora de forrajeo con la depredación de las características auditivas de las presas. Las familias con órganos auditivos encontradas corresponden a los órdenes Lepidoptera y Orthoptera. Registramos 20 familias de Lepidoptera y 5 de Orthoptera, 7 y 3 de ellas con órganos auditivos, respectivamente. De estos órdenes, las familias que carecen de oídos se registraron en la dieta de pocas especies de murciélagos. Nuestros resultados respaldan la hipótesis de la frecuencia alotónica que predice una diferencia entre los intervalos de frecuencias de emisión y audición entre el depredador y la presa. No obstante, encontramos que el consumo de mariposas carentes de oídos es menos frecuente y está relacionado a la actividad diurna y crepúscular, por lo que su consumo se limita a especies de murciélagos que inician temprano su actividad de forrajeo. Los resultados de nuestro trabajo señalan que los murciélagos exitosamente se alimentan artrópodos a pesar de la capacidad auditiva ultrasónica de las presas. Lo que se puede explicar mediante la presencia de contra-adaptaciones que permiten mantener una “carrera armamentista” asimétrica entre los murciélagos y las presas, a favor del depredador.

Myotis septentrionalis (Northern Long-eared Bat) has recently suffered a >90% decline in population size in North America due to white-nose syndrome (WNS). We assessed genetic diversity, population structure, current effective population size, and demographic history of M. septentrionalis distributed across the United States to determine baseline levels pre-WNS. We analyzed RADseq data from 81 individuals from Kentucky, Louisiana, Michigan, Minnesota, North Carolina, Oklahoma, and Wisconsin. Additionally, we examined population genetic structure using discriminant analysis of principal components, fastStructure, and STRUCTURE. We then estimated effective population size and demographic history using fastsimcoal2. Similar levels of genetic diversity were found across all samples. We found no population genetic structure in the varied analyses from these contemporary samples. The best model for demographic history estimated a rapid population expansion followed by a slower expansion approximately 340,000 years ago. The vagility of M. septentrionalis, along with male dispersal and random mating, may provide a buffer against serious bottleneck effects stemming from rapid population declines due to WNS. This research provides a baseline for tracking and monitoring the influence of WNS on genetic diversity such as potential reduced diversity or increased population structuring in the future.

Myotis septentrionalis ha sufrido recientemente una disminución de >90% en el tamaño poblacional en Norte América debido al síndrome de la nariz blanca (SNB). Evaluamos la diversidad genética, estructura poblacional, el tamaño actual poblacional efectivo y el historial demográfico de M. septentrionalis distribuidos en los Estados Unidos para determinar la información base de la especie previo al SNB. Analizamos los datos de RADseq de 81 individuos de Kentucky, Luisiana, Michigan, Minnesota, Carolina del Norte, Oklahoma y Wisconsin. Adicionalmente, examinamos la estructura genética de la población utilizando el análisis de componentes principales discriminatorio, fastStructure y STRUCTURE. Consecuentemente, estimamos el tamaño efectivo poblacional y el historial demográfico utilizando fastsimcoal2. Se encontraron niveles similares de diversidad genética en la totalidad de las muestras. Encontramos una estructura genética poblacional débil en varios análisis de estas muestras contemporáneas. El mejor modelo de historia demográfica estimó una rápida expansión poblacional seguido de una expansión más lenta hace aproximadamente 340,000 años. La vagilidad de M. septentrionalis, junto con la dispersión de los machos y el apareamiento aleatorio, puede servir como amortiguador contra los graves efectos de los cuello de botella derivados de la rápida disminución poblacional de esta especie debido a SNB.

Based on molecular and morphological evidence, we describe a new species of murine rodent from Mt. Kampalili in easternmost Mindanao Island, Philippines. It is the third known species of Tarsomys, a genus endemic to Mindanao. The new species differs from congeners (T. apoensis and T. echinatus) in having smaller body size, shorter tail, smaller hind feet, soft and dense pelage of darker color, smaller skull with a broader zygomatic plate, shorter incisive foramina, and longer auditory bullae. The new species belongs to the “Tarsomys clade” of tribe Rattini that has diversified principally on Mindanao where, in addition to the 3 species of Tarsomys, it is represented by 2 species of Limnomys and 1 species of Baletemys. The Tarsomys clade also includes the Rattus everetti complex which is widespread throughout the oceanic portion of the Philippines and likely consists of at least 4 species. Molecular phylogenetic analysis strongly supports a sister relationship between this new species and T. apoensis, which diverged approximately 1.0 to 1.75 Ma. The phylogenetic position, morphological distinctness, and relatively ancient persistence of this species support within-island diversification as the most substantial contributor to existing species richness of small mammals in the Philippines.

The New Mexico Jumping Mouse (Zapus luteus) is a federally endangered granivore active for only 3 to 5 months annually. Knowledge of diet can help guide habitat recovery and yet despite calls for restoration of its riparian habitat, the diet of Z. luteus remains largely unknown. To date, only 8 plant species have been described in the diet—whereas insectivory, mycophagy, and dietary shifts have only been hypothesized. In the late summer, Z. luteus rapidly accumulates fat for a 9-month hibernation and restoration may fail if seasonal variation in the diet is overlooked. We used DNA metabarcoding on fecal DNA (n = 165) to resolve dietary taxa within multiple trophic levels of the diet and investigate monthly patterns of consumption. Seldom studied in metabarcoding frameworks, we also investigated exogenous contamination in Sherman live-capture traps. Potential contamination among feces, pelage, and trap surfaces was detectable but low (median = 0% to 2%), with fecal communities distinct from exogenous sources. The diet of Z. luteus was varied and most frequently (frequency of occurrence) of graminoids, forbs, lepidopterans, dipterids, and false-truffles. For plant foods, dietary diversity increased throughout their season of activity, shifting from sedges and woody vegetation in the early season (June to July) to forbs and grasses in the late season (August to September). Insect consumption was consistently detected throughout the season, whereas mycophagy was more frequently detected in August, when hypogeous fungi are typically more abundant. The breadth of dietary taxa suggests plasticity in resource use, potentially accommodating diverse patterns of seed availability throughout their active period. Shifts in plant consumption may reflect a dietary adaptation to the phenological patterns of their plant communities, a synchrony that might benefit both pre- and post-hibernation survival. Our work substantially improves our understanding of the diet of Z. luteus (241 dietary taxa) and will be useful for guiding habitat recovery. It also offers scalable methods to further investigate the diet under disturbance contexts (e.g., grazing, wildfire, drought).

Over the last few decades North American flying squirrels (Glaucomys spp.) have experienced dramatic northward range shifts. Previous studies have focused on the potential effects of warming winter temperatures, yet the hypothesis that rising summer temperature had a role in these range shifts remained unexplored. We therefore sought to determine the effect of high environmental temperatures on the thermoregulation and energetics of flying squirrels in an area of the Northeast of North America with a recent species turnover. Unable to find a logistically feasible population of the northern species (Glaucomys sabrinus), we focused on Southern Flying Squirrels (G. volans). Using flow-through respirometry, we measured the relationship between metabolic rate, evaporative water loss, and body temperature at high ambient temperatures. We also measured core body temperature in free-ranging flying squirrels using temperature-sensitive data loggers. We detected no significant increase in metabolic rate up to ambient temperatures as high as 40 °C. However, evaporative water loss increased at temperatures above 36.2 °C. Free-ranging body temperature of flying squirrels followed a circadian pattern with a ∼2 °C difference between active and resting phase modal body temperatures. Rest-phase body temperatures were influenced by environmental temperatures with higher resting temperatures observed on days with higher daily maximum ambient temperatures but not to an extent that energy or water costs were significantly increased during rest. We found that, due to a relatively high level of thermal tolerance, high ambient temperatures are unlikely to cause an energetic strain on Southern Flying Squirrels. However, these findings do not preclude negative impacts of high ambient temperatures on the northern species, and these may still play a role in the changing distributions of Glaucomys in North America.

Las ardillas voladoras norteamericanas (Glaucomys sp.) han experimentado cambios dramáticos en su distribución hacia el norte durante las últimas décadas. Las investigaciones anteriores se han enfocado en los efectos potenciales del aumento de las temperaturas invernales, pero todavía no se ha explorado la hipótesis de que el aumento de la temperatura estival haya desempeñado un papel en estos cambios de rango. Por ende, deseamos determinar el efecto de las altas temperaturas ambientales sobre la termorregulación y la energía en las ardillas voladoras en una zona del noreste de América del Norte que ha mostrado un recambio de especies reciente. Estudiamos las ardillas voladoras del sur (Glaucomys volans), ya que no se pudo encontrar una población de la especie del norte (Glaucomys sabrinus) que fuera viable en términos de logística. Medimos la relación entre la tasa metabólica, la pérdida de agua por evaporación y la temperatura corporal a temperaturas ambiente altas por medio de la respirometría de flujo. Asímismo, determinamos la temperatura corporal interna de ardillas voladoras en libertad utilizando registradores de datos de temperatura. No detectamos ningún aumento estadísticamente significativo en la tasa metabólica hasta temperaturas ambiente de hasta 40 °C, pero la pérdida de agua por evaporación aumentó a temperaturas por encima de los 36,2 °C. La temperatura corporal de las ardillas voladoras en libertad siguió un patrón circadiano con una diferencia de ∼2 °C entre las temperaturas corporales modales de la fase activa y de la fase de reposo. Las temperaturas ambientales afectaron las temperaturas de la fase de reposo. Los valores de dichas temperaturas fueron más altos en los días con temperaturas ambientales máximas diarias más elevadas, pero no se presentaron aumentos significativos en los costos de energía o agua durante el reposo. Determinamos que es poco probable que las altas temperaturas ambientales causen una tensión energética en las ardillas voladoras del sur debido a un nivel relativamente alto de tolerancia térmica. No obstante, estos hallazgos no excluyen los impactos negativos de las altas temperaturas ambientales sobre las especies del norte, que podrían tener un efecto sobre las distribuciones cambiantes de Glaucomys en América del Norte.

Much historic work has focused on establishing geographical and ecological rules that broadly explain patterns in size variation. We examined geographic variation in Spotted Hyena skull size using geometric morphometrics and spatial statistics. We quantified size variation and sexual size dimorphism of the skull, and evaluated the influence of temperature, precipitation, land cover type, and population density on skull size. We found that female spotted hyenas are slightly larger on average than males. Our analysis of regional differences did not indicate geographic variation in sexual size dimorphism. Skull size of Spotted Hyenas varies with geography but does not adhere to Bergmann's Rule. The smallest individuals of both sexes occur between –5.00° and 10.00° latitude and east of 28.50° longitude, with larger individuals being found elsewhere. Although Spotted Hyena skull size co-varies in some views with such variables as habitat type and climate indicators, skull size in this species most strongly co-varies with population density. The highest population densities are associated with the smallest skull size, possibly reflecting a relationship between high population density and access to resources. These results suggest that geographic variation in Spotted Hyena skull size is better explained by the energetic equivalence rule than Bergmann's Rule.

In a recent paper titled Expert range maps of global mammal distributions harmonised to three taxonomic authorities, Marsh et al. (2022) introduced a series of new geographic range maps for all extant species of mammals and made these maps available on the Map of Life (MoL) website (www.mol.org). The title of the paper and inclusion of over 140 prominent mammalogists and biogeographers as coauthors strongly suggested that these new range maps were carefully vetted. However, when examining the maps of Marsh et al. (2022) on the MoL web platform, we found a variety of serious problems, including, but not limited to: range exaggerations (inclusion of substantial geographic areas not represented by specimen records or verified observations); range maps that are geographically shifted so that species are shown as occurring in areas in which they do not, and not occurring in areas in which they do (and in some cases, these new maps do not even encompass the type locality of a species); range maps that simply omit peripheral populations of conservation concern; and range maps for fully marine mammals (i.e., those that do not spend any time on land) that include large swaths of both insular and continental landmasses. Overall, we evaluated the new “expert” mammal range maps on the MoL platform for 78 species (retrieved between 31 March 2022 and 1 April 2023) and show that there are serious, systemic problems with these maps, and that these problems are both geographically and taxonomically widespread. As such, we caution researchers to carefully review and evaluate the range maps of Marsh et al. (2022) on the MoL before using them for any research purpose—including conservation, biogeographical, and macroecological analyses of mammals.

We welcome feedback on the range maps published in Marsh et al. (2022) where it constructively improves our knowledge on species distributions. Unfortunately, we are concerned that criticisms raised by Arbogast and Kerhoulas are steps backward, not forward, particularly as they did not access the original range map data of Marsh et al. (2022). We stress that evaluating range maps using Global Biodiversity Information Facility data without the necessary quality control and filtering will lead to flawed interpretations—using the same approach, an even greater proportion, >99.5%, of IUCN mammal range maps would fail to meet their expectations. We take this opportunity to highlight the fine-scale inaccuracies, scale limitations, and range map variance that are expected across all expert range map sources and that any researcher should consider during any analysis. Finally, we again announce the availability of an online tool for providing annotations and proposing adjustments to range maps, and suggest this as a more appropriate forum for constructively and transparently improving range maps.