Ecological factors such as temperature, precipitation, and vegetation type have been reported to influence biogeographic patterns (e.g., species distribution, richness, and endemism) in mammals. In Chile, these patterns only had been explored in selected mammal groups from certain localities. In this study, we describe and analyze biogeographic patterns for all small mammals (marsupials, armadillos, bats, rodents), reported until 2020, in different climatic and ecological regions from continental Chile. Using a compiled database of 89 species, we estimated their distributional similarity, described and characterized richness and areas of endemism using Bayesian and Parsimony Analysis of Endemism, and linked species distribution with conservation status according to the IUCN Red List. We found three similarity units of species distribution based on climate: Arid, Temperate, and Polar; higher richness and endemism in north and south-central Chile; two areas of endemism, one in north and one in south; and a hotspot in south-central Chile. Finally, species of greater conservation concern showed a similar and small distribution range. The concordance in the distribution of the species with Chilean climatic regions (as determined by precipitation and temperature) suggest that the spatial distribution of Chilean small mammals is influenced strongly by those abiotic factors. This also could explain the patterns of richness and endemism and, therefore species hotspots. Variations of climatic factors therefore should be considered in explaining biogeographic patterns and conservation plans of Chilean small mammal species, because species of greater concern tend to be associated and having similar distributional characteristics.

Factores ecológicos como temperatura, precipitación y tipo de vegetación han sido implicados en influenciar patrones biogeográficos (por ejemplo, distribución, riqueza y endemismo) de mamíferos. En Chile, estos patrones sólo se habían explorado en grupos seleccionados de mamíferos de algunas localidades. En este estudio, describimos y analizamos los patrones biogeográficos de todos los pequeños mamíferos (marsupiales, armadillos, murciélagos, roedores), registrados hasta el año 2020, en diferentes regiones climáticas y ecológicas en Chile continental. Utilizando una base de datos compilada de 89 especies, se estimó su similitud de distribución se caracterizó la riqueza de especies y áreas de endemismo utilizando Análisis Bayesiano y de Parsimonia de Endemismos, y se vinculó la distribución de las especies con su estado de conservación según la Lista Roja de la UICN. Se encontraron tres unidades de similitud de distribución de especies con base al clima: áridas, templadas y polares; una mayor riqueza de especies y endemismo en el norte y centro-sur de Chile, dos áreas de endemismo, una en el norte y una en el sur; y un “hotspot” de endemismo en el centro-sur de Chile. Finalmente, las especies de mayor preocupación en cuanto a conservación mostraron una distribución similar y un rango de distribución pequeño. La concordancia entre la distribución de las especies y las regiones climáticas chilenas (determinadas por precipitación y temperatura) sugiere que la distribución espacial de los pequeños mamíferos chilenos está fuertemente influenciada por estos factores abióticos. Esto también podría explicar los patrones de riqueza de especies y de endemismo y, por lo tanto, las áreas y el “hotspot” de especies. Las variaciones en factores climáticos, por consiguiente, deberían ser consideradas en la explicación de los patrones biogeográficos y en los planes de conservación de las especies de pequeños mamíferos chilenos, ya que las especies de mayor preocupación tienden a estar asociadas y tener patrones de distribución similares.

We conducted the first long-term and large-scale study of demographic characteristics and reproductive behavior in a wild jaguar (Panthera onca) population. Data were collected through a combination of direct observations and camera trapping on a study area that operates both as a cattle ranch and ecotourism destination. Jaguars exhibited two birth peaks: April/May and October/November, that are the end and the beginning of the wet season in the Pantanal, respectively. The average litter size was 1.43 ± 0.65. Single cubs made up a total of 65.7% of the births, and we found a slight predominance of females (1.15:1 ratio) in litters. The mean age at independence was 17.6 ± 0.98 months, with sex-biased dispersal, with all males (n = 27) leaving the natal home range and 63.6% of females exhibiting philopatry. The interbirth intervals were 21.8 ± 3.2 months and the mean age at first parturition was 31.8 ± 4.2 months. Our results estimated a lifetime reproductive success for female jaguars of 8.13 cubs. Our observations also indicate that female jaguars can display mating behavior during cub rearing or pregnancy, representing 41.4% of the consorts and copulations recorded. We speculate that this behavior has evolved as a defense against infanticide and physical harm to the female. To our knowledge, this is the first time that such behavior is described for this species. All aggressive interactions between females involved the presence of cubs, following the offspring–defense hypothesis, that lead to territoriality among females in mammals, regardless of food availability. In the face of growing threats to this apex predator, this work unveils several aspects of its natural history, representing a baseline for comparison with future research and providing critical information for population viability analysis and conservation planning in the long term.

Este é o primeiro estudo de longo prazo e em grande escala de características demográficas e de comportamento reprodutivo em uma população selvagem de onças-pintadas (Panthera onca). Os dados foram coletados por meio de uma combinação de observações diretas e armadilhamentos fotográficos em uma área de estudo que atua tanto como fazenda de pecuária quanto como destino ecoturístico. As onças-pintadas apresentaram dois picos de nascimento: abril/maio e outubro/novembro, que são o final e o início da estação chuvosa no Pantanal, respectivamente. O tamanho médio da ninhada foi 1.43 ± 0.65. Filhotes únicos representaram um total de 65.7% dos nascimentos, e encontramos uma ligeira predominância de fêmeas (proporção 1.15:1) nas ninhadas. A idade média de independência foi de 17.6 ± 0.98 meses, com uma dispersão sexo-assimétrica, com todos os machos (n = 27) deixando a área natal e 63.6% das fêmeas apresentando filopatria. O intervalo entre ninhadas foi de 21.8 ± 3.2 meses e a idade média da primeira cria foi de 31.8 ± 4.2 meses. Nossos resultados estimaram um sucesso reprodutivo médio ao longo da vida para onças-pintadas fêmeas de 8.13 filhotes. Nossas observações também indicam que as onças-pintadas fêmeas podem apresentar comportamento de acasalamento durante a criação dos filhotes ou da gestação, representando 41.4% das cortes e cópulas registradas. Especulamos que esse comportamento tenha evoluído como uma defesa contra infanticídio e danos físicos à fêmea. Segundo nosso conhecimento, está é a primeira vez que tal comportamento é descrito para esta espécie. Todas as interações agressivas entre fêmeas envolveram a presença de filhotes, seguindo a hipótese de defesa da prole, que levam à territorialidade entre fêmeas em mamíferos, independentemente da disponibilidade de alimento. Diante das crescentes ameaças a este predador de topo, este trabalho revela vários aspectos de sua história natural, representando uma base de comparação com pesquisas futuras e fornecendo informações críticas para a análise de viabilidade populacional e planejamento de conservação em longo prazo.

The diet of predators can be highly variable, which is exemplified by their ability to acclimate to a wide range of ecological conditions. Such flexibility in foraging may be a key aspect of their performance in unpredictable environments such as at the edge of the range of a species or where food availability varies greatly in time and space. Gaining information on the diets of predators under such conditions could foster our comprehension of their ecological flexibility and the potential role of predation on the population dynamics of prey. We determined the diet of wolves (Canis lupus) and black bears (Ursus americanus) in northern Québec and Labrador (Canada) within the range of two migratory caribou (Rangifer tarandus) herds: the high-abundance Rivière-aux-Feuilles herd (RFH) and low-abundance Rivière-George herd (RGH). Worldwide, decline in caribou populations has become a concern, stressing the need to better understand the factors involved in these declines, including predation. In northern Québec (RFH range), caribou was the primary year-round prey of wolves while moose (Alces alces) and muskoxen (Ovibos moschatus) were consumed in some sectors. The diet of wolves in northern Labrador (RGH range) varied seasonally, with caribou, moose, and fish as main prey during different periods throughout the year. Black bear diets varied seasonally and regionally. Among the foods we analyzed, caribou was the main source of animal protein for bears in northern Québec and northern Labrador, except during a high abundance of Ungava collared lemming (Dicrostonyx hudsonius). Only bears in northern Québec ate caribou during late summer/fall. Our results highlight the diet flexibility of wolves and black bears in northern food webs, and how their diets change in relation to the distribution and abundance of prey. Our results will help quantify the potential impact of these predators on prey populations in northern systems.

Dispersal has important implications for population ecology and genetics of a species through redistribution of individuals. In most mammals, males leave their natal area before they reach sexual maturity, whereas females are commonly philopatric. Here, we investigate the patterns of natal dispersal in the Asian black bear (Ursus thibetanus) based on data from 550 bears (378 males, 172 females) captured or removed in Gunma and Tochigi prefectures on central Honshu Island, Japan in 2003–2018. We used genetic data and parentage analysis to investigate sex-biased differences in the distance of natal dispersal. We further investigated the age of dispersal using spatial autocorrelation analysis, that is, the change in the correlation between genetic and geographic distances in each sex and age group. Our results revealed that male dispersal distances (mean ± SE = 17.4 ± 3.5 km) were significantly farther than female distances (4.8 ± 1.7 km), and the results were not affected by years of mast failures, a prominent forage source for this population. Based on an average adult female home range radius of 1.8 km, 96% of the males and 50% of the females dispersed. In the spatial autocorrelation analysis, the changes in the relationship between genetic and geographic distances were more pronounced in males compared to females. Males seem to mostly disperse at age 3 regardless of mast productivity, and they gradually disperse far from their home range, but young and inexperienced males may return to their natal home range in years with poor food conditions. The results suggest that factors driving the dispersal process seem to be population structure-based instead of forage availability-based. In females, a significant genetic relationship was observed among all individuals in the group with a minimum age of 6 years within a distance of 2 km, which resulted in the formation of matrilineal assemblages.

Intraspecific communication in mammals is well-documented but generally restricted to chemical and acoustic signaling. However, other overlooked channels, such as visual signaling, may be used to communicate among conspecifics. Here, by using experimental manipulations together with camera traps on 13 brown bear (Ursus arctos) rubbing trees in the Cantabrian Mountains (northwestern Spain), we document detailed temporal patterns and behavioral aspects of a recently discovered novel communication channel for this species, visual signaling through the trunk debarking of focal trees. Video footage showed that visual marking is a sex-, age-, and time-specific means of communication in brown bears, being performed exclusively by adult males during the mating season (mainly April–June in the study area). Trunk debarking was always associated with chemical marking and was never an isolated behavior, suggesting that visual and chemical signals might be complementary. Visual and chemical marks may provide different information; for example, visual marks could be an indicator of individual size and, thus, the dominance status of adult males looking for mating opportunities. This is the first time that evidence is provided showing that visual signaling in a large carnivore is exclusive to a specific class of individuals (adult males) and linked to reproductive needs only. Bear visual signaling not only represents an advance in our comprehension of animal communication but may also serve to easily locate the mating areas of mammals, which are crucial for large carnivore species, such as the brown bear, that frequently need specific and urgent plans for conservation and management.

La comunicación intraespecífica en los mamíferos está bien documentada, pero generalmente se limita a la señalización química y acústica. Sin embargo, otros canales ignorados, como la señalización visual, pueden ser utilizados para comunicarse entre conespecíficos. Aquí, utilizando manipulaciones experimentales junto con cámaras trampa en trece árboles de marcaje de oso pardo Ursus arctos en la Cordillera Cantábrica (noroeste de España), documentamos patrones temporales detallados y aspectos conductuales de un nuevo canal de comunicación recientemente descubierto para esta especie, es decir, la señalización visual a través del descortezado del tronco de árboles focales. Las imágenes de vídeo mostraron que el marcado visual es un medio de comunicación específico de sexo, edad y tiempo en los osos pardos, siendo realizado exclusivamente por los machos adultos durante la época de celo (principalmente entre abril y junio en el área de estudio). El descortezado del tronco siempre estuvo asociado al marcaje químico, y nunca fue un comportamiento aislado, lo que sugiere que las señales visuales y químicas podrían ser complementarias. Las marcas visuales pueden proporcionar una información diferente a las químicas, como por ejemplo el tamaño del individuo y, por tanto, el estatus de dominancia de los machos adultos en busca de oportunidades de apareamiento. Es la primera vez que se aportan pruebas que demuestran que la señalización visual en un gran carnívoro es exclusiva de una clase específica de individuos (los machos adultos) y está vinculada únicamente a las necesidades reproductivas. La señalización visual de los osos no sólo representa un avance en nuestra comprensión de la comunicación animal, sino que también puede servir para localizar fácilmente las zonas de celo de los mamíferos, lo cual es crucial para las especies de grandes carnívoros, como el oso pardo, que con frecuencia necesitan planes específicos y urgentes de conservación y gestión.

Small mammals are important to the functioning of ecological communities with changes to their abundances used to track impacts of environmental change. While capture–recapture estimates of absolute abundance are preferred, indices of abundance continue to be used in cases of limited sampling, rare species with little data, or unmarked individuals. Improvement to indices can be achieved by calibrating them to absolute abundance but their reliability across years, sites, or species is unclear. To evaluate this, we used the US National Ecological Observatory Network capture–recapture data for 63 small mammal species over 46 sites from 2013 to 2019. We generated 17,155 absolute abundance estimates using capture–recapture analyses and compared these to two standard abundance indices, and three types of calibrated indices. We found that neither raw abundance indices nor index calibrations were reliable approximations of absolute abundance, with raw indices less correlated with absolute abundance than index calibrations (raw indices overall R² < 0.5, index calibration overall R² > 0.6). Performance of indices and index calibrations varied by species, with those having higher and less variable capture probabilities performing best. We conclude that indices and index calibration methods should be used with caution with a count of individuals being the best index to use, especially if it can be calibrated with capture probability. None of the indices we tested should be used for comparing different species due to high variation in capture probabilities. Hierarchical models that allow for sharing of capture probabilities over species or plots (i.e., joint-likelihood models) may offer a better solution to mitigate the cost and effort of large-scale small mammal sampling while still providing robust estimates of abundance.

Deer have been a major resource for human populations for thousands of years. Anthropogenic activities, such as hunting, have influenced the genetic structure and distribution of deer populations. In Japan, wild Japanese sika deer (Cervus nippon) have been hunted since ancient times but have also been historically protected as sacred animals in several sanctuaries. Sika deer have been protected for over a thousand years in the religious sanctuary around the Kasuga Taisha Shrine on the Kii Peninsula, located in the center of Japan. Here, we used short sequence repeats (SSR) and mitochondrial DNA (mtDNA) to investigate the genetic diversity, population structure, and demography of Japanese sika deer inhabiting the Kii Peninsula, Japan, and discuss possible anthropogenic influences. Using SSR, three distinct genetic groups were distinguished on the Kii Peninsula: an Eastern genetic group, a Western genetic group, and an isolated genetic group with individuals in the religious sanctuary of Kasuga Taisha Shrine in Nara city. The isolated genetic sanctuary group had only the mtDNA haplotype S4. The SSR genotype data suggested a newer divergence time of the genetic groups of the religious sanctuary than would have occurred as a result of Late Quaternary climate change. This time scale coincided with the establishment of the sanctuary with Kasuga Taisha Shrine. Thus, the religious protection conserved genetic variation over a thousand years.

Identifying the factors shaping dialects can reveal selective pressures and cultural influences on acoustic signals. Translocations of species have been considered the “gold standard” for identifying population differences in vocalizations, including dialects. The North American elk (Cervus canadensis) is a species that has experienced numerous translocations, but no published studies exist on dialects in elk or any other ungulate species. Adult male North American elk utter an iconic vocalization during the breeding season, which is termed the bugle call due to the power, duration, and pitch of the sound. We investigated if dialect differences existed between three populations: a source population in Wyoming (N = 10 bulls, 132 calls) and translocated populations in Colorado (N = 13 bulls, 92 calls) and Pennsylvania (N = 20 bulls, 160 calls). Dialect differences existed between the populations in 9 of 10 measured variables, in both the frequency domain and time domain. Habitat factors (acoustic adaptation hypothesis) affecting sound transmission were inconsistently related to dialects in the populations. Genetic factors may be related to dialects, as the historically bottlenecked Pennsylvania population, with low heterozygosity and low allelic richness, exhibited the least variability in acoustic measures. Cultural transmission and vocal learning may also contribute to dialect development in this highly vocal, social ungulate species.

Ungulates are a main component in carnivore diets but determining consumption of juveniles is difficult. Past studies have used size of prey remains such as small hooves or bones to classify scat samples as containing content attributable to juveniles. Hair thickness and color may also be used, but seasonality could influence the coat of an adult by developing thinner hairs in summer that more closely resemble those from juveniles. Given this uncertainty, we aimed to quantitatively determine a hair diameter threshold to categorize the age-class of ungulate hair in scats. We obtained hair samples from captive (n = 133) and vehicle-killed (n = 5) white-tailed deer (Odocoileus virginianus) from Georgia and Virginia. We used microphotography image analysis to measure the width of hairs and their cuticular casts. We used a linear model to assess differences among body locations, age-classes, and locations along the hair strand. We also analyzed the change in hair width of juveniles as they aged. Hair diameter of adults, but not juveniles, differed significantly depending on body location, yet adult hairs were always significantly wider than those from juveniles. Juvenile hairs significantly increased in width after mid-September, when they molt into adult coats in our study area. We identified 104.2 µm measured at either 1/8 or 1/4 distance from the follicle as a threshold width to distinguish adult from juvenile hairs, with 95.3% accuracy. Our findings indicate that juvenile white-tailed deer can be distinguished from adults based on the width of hairs found in carnivore scats up until juveniles are 5 months old. More broadly, our results demonstrate that hair width may be used to classify juvenile versus adult prey remains in carnivore diet studies in other predator–prey systems.

Los ungulados constituyen un componente principal en la dieta de los carnívoros silvestres; sin embargo, es difícil determinar el consumo de ungulados juveniles por carnívoros. Estudios previos han utilizado el tamaño de los restos de las presas en heces de carnívoros, tales como pezuñas o huesos pequeños, para identificar cuales contienen material de presas juveniles. El grosor y color del pelo también puede ser utilizado para este propósito, pero la estacionalidad puede influir la composición del pelaje de los adultos, produciendo pelos más delgados con apariencia de pelaje juvenil. Debido a esta incertidumbre, nuestro objetivo fue determinar un umbral cuantitativo de diámetro de pelo que permitiera categorizar la clase de edad de los remanentes de ungulados en heces. Colectamos muestras de pelo (n = 1,510) de venado de cola blanca (Odocoileus virginianus) provenientes de individuos en cautiverio o provenientes de colisiones vehiculares en los estados de Georgia y Virginia, EEUU. Usamos análisis de fotomicrografías para medir el diámetro del pelo y su impresión cuticular. Implementamos modelos lineales para evaluar diferencias entre ubicación corporal, clase de edad y tramos a lo largo del tallo piloso. También analizamos el cambio en el grosor del pelo de los juveniles en su transición a adultos. El diámetro del pelo en adultos, pero no en juveniles, fue significativamente diferente en función de la ubicación corporal, aunque los pelos de los adultos siempre fueron significativamente más gruesos que los pelos de los juveniles. Los pelos de los juveniles incrementaron significativamente en diámetro cuando mudaron a pelaje adulto, lo que ocurre después de mediados de septiembre en nuestra área de estudio. Determinamos que 104.2 µm a un 1/8 o un 1/4 del tallo piloso desde el folículo, es el diámetro umbral para distinguir adultos de juveniles con una exactitud del 95.3%. Estos hallazgos son aplicables en estudios de análisis de dieta de carnívoros cuando hay juveniles menores de 5 meses de edad en el paisaje, con el fin de establecer la proporción de heces de carnívoros que contienen restos de presas juveniles o adultas.

The Central American brocket deer (Mazama temama) is widespread across the Mesoamerican forests, yet it remains largely unknown. Three subspecies are recognized currently within M. temama using pelage coloration as the primary diagnostic character. However, it remains unclear if there is any pattern of morphological variation throughout its distribution. We compared two models of morphological subdivision, namely the traditional subspecies and another based on biogeographic provinces via 2D geometric morphometrics and ecological niche modeling. The second model presented a better fit to the observed variation in cranial shape and size. We found divergence in skull size between individuals from Mexico and Guatemala (northern group) relative to specimens from Honduras, Nicaragua, Costa Rica, and Panama (southern group), the latter being 8% larger than the northern group. Centroid size showed a significant correlation with geographic distance suggesting an isolation-by-distance pattern. Low geographical overlap between the two clusters suggests niche conservatism. Late Pleistocene dispersal from South to Central America and differences in available resources with subsequent isolation due to climatic barriers therefore may have promoted differentiation in size albeit without extensive changes in shape. In this context, the Motagua-Polochic-Jolotán fault system probably plays a key role in promoting morphological differentiation by climatic isolation. Finally, we suggest that M. t. temama (Kerr, 1792) and M. t. reperticia Goldman, 1913 should remain as valid names for the two morphological and ecologically differentiated groups detected here.

El temazate centroamericano (Mazama temama) está ampliamente distribuido por los bosques mesoamericanos, si bien es poco estudiado. Se reconocen actualmente tres subespecies en M. temama, principalmente usando la coloración del pelaje como carácter diagnóstico primario. Sin embargo, no resulta claro si existe algún patrón de variación morfológica a lo largo y ancho de su distribución. Usando morfometría geométrica en 2D y modelado de nicho ecológico, comparamos dos modelos de subdivisión morfológica: el tradicional de subespecies y otro basado en provincias biogeográficas. El segundo presentó un mejor ajuste a la variación observada en forma y tamaño del cráneo. Encontramos divergencia en tamaño del cráneo entre individuos de México y Guatemala (grupo norteño) con respecto a especímenes de Honduras, Nicaragua, Costa Rica y Panamá (grupo sureño), siendo estos últimos 8% más grandes que los del grupo norteño. El tamaño de centroide demostró una correlación significativa con la distancia geográfica, sugiriendo así un patrón de aislamiento por distancia. La reducida coincidencia geográfica entre los dos grupos sugiere conservadurismo de nicho por parte de estos. La dispersión de Sudamérica a Centroamérica durante el Pleistoceno tardío y las diferencias en disponibilidad de recursos, seguidas por aislamiento debido a barreras climáticas, pudieron por tanto promover una diferenciación en tamaño, aunque sin cambios importantes en la forma. En este contexto, el sistema de fallas Motagua-Polochic-Jolotán probablemente juega un papel importante, llevando a diferenciación morfológica por aislamiento climático. Finalmente, sugerimos que los nombres M. t. temama (Kerr, 1792) y M. t. reperticia Goldman, 1913 deberían permanecer como válidos para los dos grupos detectados en este estudio, diferenciados morfológicamente y ecológicamente.

Plant–animal interactions constitute some of the most important ecological processes for the maintenance of tropical forests. Bats are the only group of mammals capable of true flight and have been recognized as important dispersers of pioneer and secondary successional plant species. Although progress has been made in the study of Neotropical bats, morphological variation of the wing and its influence on niche separation between species is unknown. We evaluated relationships among habitat structures of selected Colombian tropical dry forest patches, the diet through interaction networks, and wing morphology of 11 species of bats in the Stenodermatinae subfamily (297 individuals) using geometric morphometry in a phylogenetic context. The results indicate that the phylogenetic signal for wing size is greater than for wing shape, thus providing some evidence for evolutionary convergence. Wing shape variation was associated primarily with the distal anatomical tip of the third finger and the joint between the humerus and the radius and ulna. Species with wide, short wings, as in the genus Artibeus had generalist diets and less nested positions within the interaction networks. In contrast, species with elongated and pointed wings, such as Sturnira and Platyrrhinus, had specialized diets and more nested positions within the interaction networks. We argue that wing shape variation may play an important role as a source of interspecific variation leading to food specialization within tropical bat communities.

Las interacciones planta-animal constituyen algunos de los procesos ecológicos más importantes para el mantenimiento de los bosques tropicales. Los murciélagos son el único grupo de mamíferos capaces de un verdadero vuelo y han sido reconocidos como importantes dispersores de especies de plantas pioneras y de sucesión secundaria. Aunque se ha avanzado en el estudio de los murciélagos neotropicales, se desconoce la variación morfológica del ala y su influencia en la separación de nichos entre especies. Evaluamos las relaciones entre las estructuras de hábitat de parches seleccionados de bosque seco tropical colombiano, la dieta a través de redes de interacción y la morfología alar de 11 especies de murciélagos de la subfamilia Stenodermatinae (297 individuos) usando morfometría geométrica en un contexto filogenético. Los resultados indican que la señal filogenética para el tamaño del ala es mayor que para la forma del ala, lo que proporciona alguna evidencia de convergencia evolutiva. La variación de la forma del ala se asoció principalmente con la punta anatómica distal del tercer dedo y la articulación entre el húmero y el radio y el cúbito. Las especies con alas cortas y anchas, como en el género Artibeus, tenían dietas generalistas y posiciones menos anidadas dentro de las redes de interacción. En contraste, las especies con alas alargadas y puntiagudas, como Sturnira y Platyrrhinus, tenían dietas especializadas y posiciones más anidadas dentro de las redes de interacción. Argumentamos que la variación de la forma del ala puede desempeñar un papel importante como fuente de variación interespecífica que conduce a la especialización alimentaria dentro de las comunidades de murciélagos tropicales.

We describe a population of pipistrelle-like bats from Príncipe Island (Gulf of Guinea, Western Central Africa) as a new species based on the molecular and morphological characteristics of six specimens collected more than 30 years ago. The description of this new species was not possible until the traditionally entangled systematics of the whole pipistrelle group was clarified in recent years with the inclusion of molecular techniques and adequate species sampling. In this new taxonomic framework, the new species was clearly included within the dark-winged group of the recently described genus Pseudoromicia. The pipistrelles from Príncipe Island present a moderately inflated skull in lateral view with inner upper incisors that are moderately bicuspids and a baculum distinctly long with expanded tips. Besides these morphological characters, the new bat species is distinguished by its dwarfism, being the smallest species recognized within the genus. The ecology and conservation status of this endemic island species are unknown and field studies are urgently needed to evaluate the situation and conservation threats to this new species in its natural habitat.

The coastal dunes of the southeast of Buenos Aires province, Argentina, present two different described species of tuco-tucos: Ctenomys talarum and C. australis. Formerly, C. talarum was subdivided into three subspecies (C. t. talarum, C. t. recessus, and C. t. occidentalis), mainly based on its geographic distribution and phenotypic variation in characters of external morphology (e.g., body size and pelage color). This study assesses the phylogenetic relationships of C. talarum, focusing on the populations at the western end of its coastal distribution (localities of Pehuen-Có and Sauce Grande), which have been previously identified as highly genetically divergent. In this regard, populations distributed throughout the range of the species were sampled. Complete DNA sequences of the mitochondrial cytochrome b gene (1,140 bp), partial sequences of the mitochondrial D-loop region (426 bp), and partial sequences of the nuclear DNA intron 8 of the β-fibrinogen (about 870 bp) gene were used for the analyses. Phylogenetic inferences based on mitochondrial and nuclear markers were performed separately or combined to obtain a species tree. Populations distributed at the western end of the coastal dunes (between Pehuen-Có and Sauce Grande), previously assumed as C. talarum, were found to belong to an independent lineage relative to the other populations from the Pampas region. The average genetic distance between these two lineages is within the order of the genetic distances observed between different species of the genus. Also, our results show that this lineage of Ctenomys presents a high affinity with the magellanicus group, which is distributed further south, in Patagonia. In conclusion, tuco-tuco populations occurring in the coastal expanse between these two localities should be considered a possible distinct cryptic species, highly differentiated from C. talarum.

Las dunas costeras del sureste de la provincia de Buenos Aires, Argentina, cuentan con dos especies descritas de tuco-tucos: Ctenomys talarum y Ctenomys australis. Originalmente, C. talarum se subdividió en tres sub-especies (Ctenomys talarum talarum, Ctenomys talarum recessus y Ctenomys talarum occidentalis), basándose principalmente en su distribución geográfica y en la variación fenotípicade caracteres morfológicos externos (p. ej., tamaño corporal y color del pelaje). Este estudio evalúa las relaciones filogenéticas de C. talarum, centrándose en las poblaciones del extremo occidental de su distribución costera (localidades de Pehuen-Có y Sauce Grande), las cuales han sido previamente identificadas como genéticamente muy divergentes. En este sentido, se muestrearon poblaciones en todo el rango de distribución de la especie, tanto en áreas costeras como continentales (lejos de la costa). Para los análisis se utilizaron secuencias completas de ADN mitocondrial del citocromo b (1,140 pb), secuencias parciales de la región mitocondrial D-loop (426 pb), y secuencias parciales de ADN nuclear del intrón 8 del gen del fibrinógeno β (aproximadamente 870 pb). Las inferencias filogenéticas basadas en marcadores mitocondriales y nucleares, individuales o combinadas para obtener un árbol de especies, mostraron que las poblaciones distribuidas en el extremo occidental de las dunas costeras (entre Pehuen-Có y Sauce Grande), previamente consideradas como C. talarum, pertenecen a un linaje independiente en relación al resto de las poblaciones de la región pampeana. La distancia genética promedio entre estos dos linajes, para todos los datos analizados, se encuentra dentro del orden de magnitud de las distancias genéticas observadas entre diferentes especies del género. Asimismo, los resultados muestran que este linaje de Ctenomys presenta una alta afinidad con el grupo magellanicus, que se distribuye más al sur, en la zona de la Patagonia. En conclusión, las poblaciones de tuco-tucos que se encuentran entre estas dos localidades costeras, deben considerarse una posible especie críptica, altamente diferenciada de C.talarum.

The expansion of agriculture in equatorial areas is fragmenting and reducing wildlife habitats. For primates, it also increases opportunities to consume crops as high-energy resources, exacerbates conflicts with farmers, and increases exposure to diseases and agrochemicals at the edge of protected areas. In species with sex differences in ranging behavior, individual exposure to such opportunities and threats may vary by sex. Chimpanzees show a great feeding flexibility and are territorial species with varied ranging patterns according to site, sex, or individuals. Within a community whose territory is crossed by a high-traffic road and partially bordered by maize gardens, we tested hypotheses of interindividual differences in access to crops based on age, sex, ranging behavior, and kinship. By analyzing the presence of Sebitoli chimpanzees (Pan troglodytes schweinfurthii, Kibale National Park, Uganda) on video clips from 16 camera traps, we estimated the individual dispersion range across the community's territory and the crop foraging frequency along maize gardens over 16 months. While all age and sex classes were represented at the forest–garden interface, large intrasex differences were observed: some mature males and females were not observed to participate. The crop foraging frequency of adult females in maize gardens was significantly correlated with the location of their ranging areas. Related individuals revealed similar range patterns within the forest territory without sharing crop foraging habits. However, social learning and energy and risks–benefits trade-offs as potential drivers of crop consumption are not excluded.

It is known that climatic factors can influence the reproductive performance of small mammal populations. However, this information has not been available for the big-eared woodrat (Neotoma macrotis), a keystone species that inhabits the California central coast ranges south to Mexico and the oak woodlands (Quercus spp.) of the western Sierra Nevada foothills. From 2002 to 2014, we livetrapped woodrats on 1.1-ha study plots in coastal-central California and recorded their age and reproductive status. We analyzed these data by a capture-mark-recapture (CMR) framework to estimate state-specific recapture probability (p) and monthly apparent survival (S) of juvenile, non-reproductive, and reproductive adult female woodrats, and the influence of rain and temperature on S and transition probability (Ψ) of the three states. Rainfall from the previous season did not markedly affect survival rates of the states, with one exception: it decreased the survival of nonreproductive woodrats. Nearly all breeding occurred during the cool, wet winter season. Juvenile woodrats had at least a 0.55 probability of breeding by their first winter, conditional on survival. Temperature during the breeding season had a marked negative influence on transition probability. During winter, survival of nonreproductive adult females was significantly higher than for juvenile and reproductive females, indicating a cost of reproduction. Physiological effects and diminished diet quality due to further climate warming could reduce the reproductive success of female big-eared woodrats with negative consequences on population growth and persistence.

Los factores climáticos pueden generar un impacto en el desempeño reproductivo de mamíferos de talla pequeña. Sin embargo, no hay información disponible para la rata magueyera (Neotoma macrotis), una especie clave que habita la costa central de California, con una distribución que se extiende desde el sur de México hasta las faldas de los bosques de robles en el oeste de la Sierra Nevada. Desde el año 2002 al 2014, en la costa central de California se colectaron ejemplares vivos de la rata magueyera en parcelas de 1,1 ha., registrando la edad y estadio reproductivo de cada captura. Los datos colectados fueron analizados utilizando un modelo multiestado de captura-marca-recaptura (CMR), con el propósito de estimar la probabilidad de recaptura estadio-específico (p), la supervivencia aparente mensual (S), y la influencia de la lluvia y la temperatura en la tasa de supervivencia y probabilidad de transición (Ψ) en individuos juveniles y en hembras adultas en estadio reproductivo y no reproductivo. Las lluvias de la temporada anterior no afectaron marcadamente las tasas de supervivencia de los estadios, a excepción de un decrecimiento en la supervivencia de la rata magueyera en estadio no reproductivo. En su mayoría, la reproducción ocurrió durante la estación fría y húmeda del invierno. Los individuos juveniles tuvieron al menos una probabilidad de 0,55 de reproducirse en su primer invierno, condicional para la supervivencia. La temperatura durante la estación reproductiva tuvo un notable impacto negativo en la probabilidad de transición. Durante el invierno, la supervivencia de las hembras adultas no reproductivas fue significativamente mayor que las juveniles y las hembras en estadio reproductivo, evidenciando el costo de la reproducción. Los efectos fisiológicos y la disminución en la calidad de la dieta, como consecuencias del calentamiento climático, podrían reducir la tasa de reproducción de las hembras de rata magueyera, generando consecuencias negativas en el crecimiento poblacional y su persistencia.

The ecology, life histories, and physiology of many animals are changing in response to human-induced climate change. As the Earth warms, the ability of an animal to thermoregulate becomes ecologically and physiologically significant. Morphological adaptations to warmer temperatures include larger appendages and smaller bodies. We examined morphological features in a ground squirrel, Xerus inauris, living in the arid zones of South Africa, to examine whether squirrels have responded to increases in temperature and changes in seasonal rainfall with morphological modifications over the last 18 years. We found that over time, absolute hindfoot length and proportional hindfoot length increased, while spine length decreased. These changes are consistent with ecogeographical rules (Allen's rule and Bergmann's rule) and provide evidence in support of “shape-shifting” in response to climatic warming. Body mass also increased with time; however, these changes were not consistent with Bergmann's rule, indicating that mass is influenced by other ecological factors (e.g., resource availability). Our study adds to the growing evidence that animal morphologies are changing in response to changing climatic conditions, although it remains to be seen whether these changes are adaptive.