Of the 116 mammal species present in the Greater Antilles at the start of the Holocene Epoch, only 56 now survive, with more extensive species losses (∼80%) in native lineages of sloths, shrews, rodents, and primates than in bats (∼25%). Native species occurrences and extinctions are summarized herein for Cuba, Hispaniola, Jamaica, and Puerto Rico and used to introduce this Journal of Mammalogy Special Feature on insular Caribbean mammals. Recent efforts to understand extinct and extant Caribbean mammal diversity highlight the utility of paleobiological perspectives for exposing the trajectory of species losses and informing how best to protect remaining biodiversity in this region.

The insular Caribbean is among the few oceanic-type island systems colonized by non-volant land mammals. This region also has experienced the world's highest level of historical mammal extinctions, with at least 29 species lost since AD 1500. Representatives of only 2 land-mammal families (Capromyidae and Solenodontidae) now survive, in Cuba, Hispaniola, Jamaica, and the Bahama Archipelago. The conservation status of Caribbean land mammals is surprisingly poorly understood. The most recent IUCN Red List assessment, from 2008, recognized 15 endemic species, of which 13 were assessed as threatened. We reassessed all available baseline data on the current status of the Caribbean land-mammal fauna within the framework of the IUCN Red List, to determine specific conservation requirements for Caribbean land-mammal species using an evidence-based approach. We recognize only 13 surviving species, one of which is not formally described and cannot be assessed using IUCN criteria; 3 further species previously considered valid are interpreted as junior synonyms or subspecies. Of the 12 reassessed species, 5 have undergone a change in threat status since 2008, with 3 species (Capromys pilorides, Geocapromys brownii, Mesocapromys angelcabrerai) increasing in extinction risk by 1 IUCN category, and 2 species (Plagiodontia aedium, Solenodon paradoxus) decreasing in extinction risk by 2 categories. Only 1 change in threat status represents a genuine change; all other changes are mainly associated with new information becoming available. Hunting, habitat loss, and invasive species represent major threats to surviving species, and conservation of the highly threatened Caribbean land-mammal fauna will require a range of targeted management strategies.

The Jamaican primate, Xenothrix mcgregori, regarded variously as either a pitheciid or a stem platyrrhine, was the terminal branch of a clade that likely entered the West Indies at least as early as the Early Miocene, although its lineage is represented by fossils of Quaternary age only. We present a new direct radiocarbon-based date of 1,477 ± 34 calibrated years before present (cal BP) for the last documented appearance of this species in the fossil record. We employed the Gaussian-resampled, inverse-weighted McInerny et al. (GRIWM) method to estimate the extinction date of X. mcgregori, based on the data presented here as well as 6 other dates derived from X. mcgregori sites. On this basis, we estimated a last occurrence ∼900 BP. The cause or causes of this extinction, as well as the many others that occurred in late Quaternary of the Greater Antilles, remain a matter of debate. The likeliest inference is that these losses were largely if not completely anthropogenically driven. Although many species and populations of primates are critically threatened today, the loss of X. mcgregori stands as the most recent species-level extinction within Anthropoidea corroborated by radiometric evidence.

The insular radiation of hutias is remarkable among mammals for its high rate of extinction during the Holocene (∼58% of species), yet fragments of intact habitat throughout the West Indies retain a critical portion of endemic diversity needing assessment. Cuba contains 8 of the 11 recognized living species of hutias, with surviving forms also on Hispaniola, Jamaica, and the Bahamas. Herein, we performed molecular phylogenetic analyses across populations of Cuban hutias in the genera Capromys, Mesocapromys, and Mysateles to address major gaps in our understanding of their species limits, phylogenetic structure, and geographic distributions. Comparing sequences of mitochondrial genes (cyt-b, COI, 12S rRNA) from 41 individuals and 21 sites across the archipelago, we found evidence that Capromys pilorides contains a major species-level subdivision from western to eastern Cuba, spanning a greater geographic region than previously hypothesized. Populations of Capromys in each clade last shared a common ancestor ∼1.1 million years ago (Ma; 5.2% cyt-b divergence). The western clade is further subdivided between mainland hutias (C. p. pilorides) and those on Isla de la Juventud plus Cayo Cantiles (C. p. relictus has priority). The eastern clade contains all Capromys east of Sierra del Escambray in central Cuba, including mainland and insular forms. However, without paired analyses of morphology and genetics or data from type localities, we cannot assign a name to the eastern Capromys sp. nov. at this time. Divergencetime analyses across 9 named species of hutias (plus 1 extinct), including nuclear genes (GHR, vWF, RAG1), dates the Capromyidae split from their South American relatives (Echimyidae) at 15.5 Ma. The crown radiation of hutias was 8.8 Ma, with successive divergences at 5.4 Ma (Geocapromys), 3.1 Ma (Capromys), and 2.2 Ma (Mysateles–Mesocapromys). Detailed surveys are needed to assess the conservation status of these evolutionarily distinct Cuban taxa.

Land mammals of the Caribbean Islands biodiversity hotspot have suffered a high rate of extinction since human arrival, principally in the last 500 years since colonialism began. Here, we present an extensive review and bibliography of this topic in Cuba, including details regarding the surviving endemic species of volant and terrestrial mammals and locations of species on 121 protected areas. We analyzed patterns of species richness, endemism, body mass, diet, habitat, geographic distribution of the observed richness, conservation threats, and possible causes and threats to future extinction. Cuban mammal biodiversity is comprised of 59 native species, 24 extinct species and 35 extant species, most of which are endemic to the Cuban archipelago. We compared the threats of habitat destruction and hunting, with emphasis on invasive mammal species as drivers of historical extinction in Cuba. A total of 44 mammal species have been introduced since 1509, with 33 invasive species living in the wild and exerting differing degrees of impact, principally by predation and competition. Additionally, we evaluated interactions among invasive and native mammals, emphasizing predation of feral cats upon Solenodon cubanus, Capromys pilorides, and other small endemic vertebrates as determined from analyses of scat contents. We found that black rats (Rattus rattus) reach densities of 147–322 individuals/ha in Solenodon habitat, thus likely are major competitors for food and refuges to these evolutionarily distinct and endangered Cuban mammals.

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The majority (90%) of native terrestrial mammal species living in the Dominican Republic are bats, and two-thirds of these species are endemic to the Caribbean. However, recent molecular studies using DNA barcoding of the mitochondrial cytochrome c oxidase subunit 1 gene have suggested at least a 25% underestimation of biodiversity in bats throughout the world. A recent survey of bats in the Dominican Republic documented 15 of the 18 known species on the island of Hispaniola. Phylogenetic analysis of 132 individuals resulted in well-supported monophyletic species-level clades (maximal bootstrap values) with intraspecific variation ranging from 0% to 4.7% and interspecific variation ranging from 14.1% to 32.5%. A phylogeographic pattern separating the northern and southern Dominican Republic was recovered in 3 species of bats (Macrotus waterhousii, Pteronotus parnellii, and Pteronotus quadridens). The inclusion of broader geographic sampling across the Neotropics indicated that 3 widely distributed species (Eptesicus fuscus, Molossus molossus, and Monophyllus redmani) have high sequence divergence among insular or between insular and continental populations. Further systematic study is needed to identify morphologically cryptic species and their implications for conservation priorities in the Caribbean.

We describe a new species of Myotis (Vespertilionidae, Myotinae) from the Republic of Trinidad and Tobago, Tobago Island. The new species (Myotis attenboroughi sp. nov.) can be distinguished from all other Neotropical congeners by cranial features and cytochrome-b gene sequences. Myotis attenboroughi sp. nov. is allied morphologically with species in the albescens group (like M. nigricans), and is sister to a clade including M. cf. handleyi, M. nesopolus, and 3 possibly undescribed species from Central and South America. A review of Myotis collections from the Caribbean confirms M. nyctor for Barbados and Grenada; M. dominicensis for Dominica and Guadeloupe; M. martiniquensis for Martinique; M. pilosatibialis and M. riparius for Trinidad; and M. attenboroughi for Tobago. The occurrence of M. attenboroughi on Trinidad is still an open question.

We examined geographic trends in 4 morphological data sets (both craniodental and colorimetric measurements and scores of cranial foramina and qualitative craniodental variables) within and among 5 subspecies of the California vole, Microtus californicus, that occur within or adjacent to the Mojave Desert in eastern California. These analyses are corollary to those previously published on the same samples using both mitochondrial and nuclear gene sequences and microsatellite loci. The morphological and molecular data sets are generally concordant in supporting the existing infraspecific taxonomy, although important conflicts are evident. With the combination of data sets, we are able to assign previously unknown samples to these infraspecific taxa. We define and provide an emended diagnosis of each subspecies using the criteria established by Willi Hennig in his 1966 assessment of the qualities and characteristics of infraspecific taxa, which he understood to be fundamentally different than the hierarchical phylogenetic system he established as the conceptual framework for taxa at the species level and above. Hennig's views are contrary to how the subspecies concept has been applied in much of recent mammalian taxonomy.

The genus Glaucomys (New World flying squirrels) is currently considered to be comprised of 2 species, the northern flying squirrel (G. sabrinus) and the southern flying squirrel (G. volans). We synthesize new information from mitochondrial DNA (mtDNA) control region sequences and microsatellite data to demonstrate that the genus consists of 3, rather than 2 species, and that Glaucomys sabrinus, as currently recognized, is actually composed of 2 separate, apparently non-hybridizing species. Control region mtDNA data from 185 individuals across North America revealed 2 distinct clades embedded within G. sabrinus: a widespread “Continental” lineage and a more geographically restricted “Pacific Coastal” lineage. The geographic distributions of these 2 lineages are largely mutually exclusive, with sympatry observed at only 3 sites in the Pacific Northwest. Analysis of 8 microsatellite loci showed no evidence of hybridization between the 2 lineages of G. sabrinus in the region of sympatry. This lack of gene flow is noteworthy given that populations of the Continental lineage of G. sabrinus have been shown to hybridize with G. volans in southeastern Canada. Finally, phylogenetic analyses and estimates of divergence times show that G. volans and Continental G. sabrinus are actually sister taxa that diverged from one another more recently than either did from Pacific Coastal G. sabrinus. We propose that these observations provide strong evidence for a third, previously unrecognized species of North American flying squirrel, whose geographic range extends along the Pacific Coast from southern British Columbia to southern California. Glaucomys oregonensis (Bachman, 1839), whose type locality is in Oregon, is the senior available name for this taxon. We propose that this newly recognized species be given the common name “Humboldt's flying squirrel.”

Of the 19 currently recognized species of Sylvilagus Gray, 1867, 15 inhabit North America, and only 5 are recognized in South America: S. brasiliensis Linnaeus, 1758 (throughout most of the continent); S. varynaensis Durant and Guevara, 2001, restricted to the southern lowlands of Venezuela (states of Barinas, Portuguesa, and Guarico); S. andinus (Thomas, 1897) from the Andean páramos of Ecuador and potentially in a sporadic manner to the Colombian and Venezuelan páramos; and S. tapetillus Thomas, 1913, from the coastal plain in the region of Rio de Janeiro. In addition to these, putative subspecies of S. floridanus, primarily a North American taxon, nominally are recognized from the grassland plains areas of northwestern South America east of the Andes. While S. varynaensis and S. tapetillus are monotypic, S. brasiliensis contains at least 37 named taxa in synonymy, distributed in various habitats; S. andinus requires further study. As a result of the recent description of a neotype for S. brasiliensis, it is now possible to assess species limits and begin the process of illuminating formerly obscured biological diversity in South American cottontails. Here, I describe a new species of Sylvilagus from the lowlands of western Suriname, and excise S. sanctaemartaeHershkovitz, 1950 from synonymy with S. brasiliensis.

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Two subspecies of Andinomys edax are currently recognized. Andinomys e. edax ranges from southern Perú to northernmost northwestern Argentina and A. e. lineicaudatus is mainly distributed in southern northwestern Argentina. However, some workers have recognized both taxa as distinct species, stating that A. edax is restricted to Puna and Prepuna habitats between 2,000 and 4,800 m elevation, whereas A. lineicaudatus occurs in Yungas forest below 2,500 m. We assessed the taxonomic status of both forms through an integrative approach including morphological (discrete skin and skull characters), morphometric (univariate and multivariate), geographicenvironmental niche modeling (Mahalanobis Typicalities), and molecular (Bayesian analysis of cytochrome-b gene sequences) analyses. We did not find characters that consistently differentiated skins and skulls of the 2 forms. The morphometric analysis indicated that lineicaudatus is, on average, larger than edax for some measurements, but only 2 (alveolar width and occipital condyle width) differed significantly between forms. No group of specimens was clearly segregated in the PCA morphospace. Distribution models obtained separately for each taxon do not offer a better fit to the known distribution than models based on the combined data sets. We documented coincident environmental variables as relevant in the model building of edax and lineicaudatus, noting some segregation in elevation, but similar habitat suitability for the remainder of the environmental variables. The geographic continuity between niche models of edax and lineicaudatus was clear but specimens morphologically assignable to each of the nominal forms were not found in areas of overlap. The phylogenetic analyses recovered a polytomy of 4 allopatric and genetically divergent clades, which also failed to support the taxonomic hypothesis of 2 species. Based on all available evidence, we conclude that Andinomys consists of a single species. Nevertheless, observed genetic divergences among clades and their geographic distribution indicate that past events probably fragmented populations of A. edax.

Efforts to restore large carnivores often are conducted with an assumption of reciprocity, in which prey populations are expected to return to levels approximating those prior to carnivore extirpation. The extent to which this assumption is met depends on the intensity of predation, which in turn can be influenced by the magnitude of environmental change over the period of large-carnivore extirpation. Recent declines of hartebeest (Alcelaphus buselaphus) populations in Laikipia, Kenya have coincided with recolonization by large carnivores, particularly lions (Panthera leo), over the past 20 years. To understand whether and the extent to which predation by lions underlies hartebeest declines, we monitored vital rates of hartebeest that were variably exposed to or protected from lions. Lion exclusion shifted rates of population growth from negative to positive (λ = 0.89 ± 0.04 versus 1.11 ± 0.11 for control and lion exclusion zones, respectively) and, consistent with other studies on ungulate demography, adult survival was the most sensitive and elastic vital rate. Analysis of life table response experiments revealed that 32% of the variation in population growth was due to fecundity, which had the greatest proportional effects on λ. In addition, hartebeest selected open (grassland) areas more strongly where lions occurred, and avoided areas with dense tree cover. Our work provides experimental evidence to support the hypothesis that hartebeest declines have been driven primarily by lion restoration, although we cannot eliminate the possibility that predation by spotted hyenas (Crocuta crocuta) additionally suppressed populations of hartebeest. Given that tree cover has increased across Laikipia over the past 50 years, we suggest that lion-driven declines of hartebeest have been exacerbated by landscape change.

Roaring is an integral component of African lion (Panthera leo) ecology as it facilitates social cohesion and territorial defense. Despite the importance of roaring, there is a limited understanding of the configuration of this behavior in spatiotemporal dimensions. Here, we mapped the configuration of lion roaring at the home-range scale and quantified temporal signatures in roaring frequency. We tested whether spatiotemporal patterns of roaring vary with position within a lion dominance hierarchy using a dominance shift that occurred in a reintroduced group of lions. We collected spatially explicit roaring data from continuous follows of 6 telemetered lions in Addo Elephant National Park, South Africa, for a 24-month period after release. We assessed the frequency and location of roaring before and after a dominance shift. We developed utilization distributions to describe space use at the coalition level for males and individually for females. We plotted the frequency of roaring for these coalitions and females as a group in each period. The spatiotemporal patterns in roaring were closely tied to social dynamics and the imminent dominance shift experienced in this population. These patterns highlighted a distinct shift in roaring strategy, especially in the newly subordinate male coalition, which substantially reduced their roaring from 10 to ~3 roars per follow, altered their space use, and altered the spatial configuration of their roaring behavior from the periphery of their home range when they were dominant to nearer to the core (averaging ≤ 31st percentile) of their home range when they became subordinate. While our findings were based on a limited sample, our study suggests that the spatial strategy and frequency of roaring varies in relation to social rank and patterns in space use of rival coalitions.

Socio-ecological theory asserts that mating strategies are dictated by the distribution of females and the ability of males to monopolize them. Within several bottlenose dolphin (Tursiops truncatus) populations, males demonstrate a relatively rare mating strategy: cooperative mate guarding within alliances. Dolphin alliances vary in complexity, but to date, documentation of multi-level alliances has been limited to Shark Bay, Australia. Given the rarity of male reproductive alliances, opportunity for comparative study is limited. This study is the 1st documentation of the complexity of male dolphin alliances in estuarine waters along the Atlantic coast of the United States. Photo-identification data were collected from March 2011 to 2014 in the St. Johns River (SJR) in Jacksonville, Florida. Analyses included individuals sighted 10+ times and were divided into females (n = 78), males (n = 25), and unknown sex (n = 78). Thirty individuals met the criteria for alliance status and 20 individuals formed 2nd-order alliances. Results fit the sex-specific association patterns described for other populations, with low-moderate bonds (half-weight indices) between females and markedly stronger bonds among males and individuals of unknown sex. Comparative studies between the SJR and Shark Bay, Australia, as well as with nearby and ecologically similar field sites are needed to determine the selective pressures (ecological and demographic) shaping alliance complexity.

Eastern populations of the Eurasian otter (Lutra lutra) have declined throughout Asia. Although the South Korean government designated the Eurasian otter as an Endangered Species and Natural Monument, limited information exists on the distribution and habitat of this top predator in riparian ecosystems at this terminus of its distribution. We documented the distribution and modeled the habitat of this species using sign survey data collected in 2009 and 2010. We analyzed otter presence with 21 raster data sets using environmental niche modeling. We evaluated 31 variables as explanatory variables for logistic regression models that considered detection and non-detection data. We detected otter sign at 83% (3,288 of 3,957) of survey sites within 63% (680 of 1,074) of survey cells. In our MaxEnt presence-only model, land cover type was the main contributing factor to predicting habitat suitability, with secondary influences from isothermality, precipitation in the wettest month, elevation, and temperature seasonality. Water quality and human disturbance were the main variables significantly associated with otter occurrence based on the regression model that included detection and non-detection data. Direct measures of human activity, such as traffic volume and land price, were better predictors than stationary factors such as density of buildings. Our results suggest that otters and humans can coexist in highly populated areas. Our information on the distribution and habitat characteristics of Eurasian otters in South Korea will assist habitat management and recovery projects in natural and anthropogenic environments.

One of the benefits of modeling habitat selection for a given population is the ability to predict patterns in another population that inhabits an ecologically similar area. We studied habitat selection and home ranges of reintroduced and wild giant anteaters (Myrmecophaga tridactyla) in 2 South American wetlands (Iberá, Argentina, and Pantanal, Brazil). Nine reintroduced (Iberá) and 10 wild (Pantanal) adult animals were tracked via VHF and GPS between 2007 and 2015. We used resource selection functions to assess habitat selection for the wild anteaters from Pantanal. Generalized linear mixed models were constructed for resting and activity periods during both the wet and dry seasons. We then validated previous models built for reintroduced anteaters in Iberá using data from the wild animals from Pantanal. Habitat type (floodplain, grassland, open savanna, closed savanna, and forest) and distances to selected landscape traits were used as covariates. Locations near forests were positively selected in both populations. Selection of forests in Pantanal was less evident than in Iberá, probably due to the much higher availability of forests in the Brazilian site, with 38–53% of the landscape classified as good-to-high likelihood in Pantanal compared to only 4% in Iberá. Mean home-range size of males was larger in Iberá (32.50 ± 7.64 km²) than in Pantanal (14.07 ± 1.97 km²), whereas home-range sizes of females were similar in both areas (9.75 ± 1.74 km² in Iberá; 9.62 ± 2.00 km² in Pantanal). Results of this study suggest that model validation with geographically independent data is a useful tool to compare reintroduced and wild populations and to identify resources or landscape attributes that are important for a given species, even when these resources are abundant or highly available.

How species respond to changes caused by habitat loss and fragmentation depends on the habits and habitat selection of individuals, but most studies focus on community- or population-level consequences. One reason could be the difficulty in determining what individuals of a species perceive as habitat. Herein, we determine how habitat fragmentation changes fine-scale habitat use of the marsupial Philander frenatus. We compared daily home range (DHR), path tortuosity (D), and aboveground use of the forest (AG) between 2 fragments and a continuous area of Atlantic Forest in Brazil. Adult opossums were tracked with a spool-and-line device, allowing a detailed mapping of the animals' paths. In fragments, individuals covered a smaller area in 1 night of activity with a less tortuous path but used the vertical strata of the forest more often. DHR was larger in the dry season, when resources are less abundant, and for larger individuals, as expected. Despite being able to move between fragments, most parts of individual paths in fragments were concentrated in the edge, which also acted as a physical limit to the daily activities of opossums. The ability of P. frenatus to persist in fragmented landscapes is evident but depends on the ability to move between fragments, frequent use of the edge, and use of the forest upper strata. Future studies could evaluate if other species of marsupials and small mammals may persist in fragmented landscapes through similar mechanisms.

The raccoon (Procyon lotor) is an ecologically important mesopredator that threatens at least 11 species of beach-nesting and colonial waterbirds on the Virginia barrier islands. An understanding of population dynamics, reproductive sources and sinks, and dispersal pathways among the islands and the adjacent Delmarva Peninsula mainland will help prioritize allocation of scarce resources for managing these raccoon populations. We characterized these metapopulation processes by examining variation across mitochondrial (mtDNA) and nuclear DNA (microsatellite) markers. We sequenced a 515-base pair fragment of mtDNA (containing the 5′-end of the cytochrome-b gene, the 3′-end of the D-loop, and the intervening tRNA genes) in 164 animals from 22 localities. We detected 7 unique mtDNA sequences, distributed along a presumably long-term, north–south genetic gradient on the islands and on the mainland, reflecting the temporal sequence of colonization of these areas. We also genotyped 13 nuclear microsatellite loci in 314 individuals from 24 localities, and we found complex patterns of spatial population structure, dispersal, and gene flow among island and mainland localities. Whereas mainland localities showed considerable admixture, suggesting multiple waves of colonization, most islands showed little admixture, suggesting single founding events and relative isolation since founding. Islands formed 2 genetically cohesive groups, 1 in the north and another in the south. Based on patterns of genetic variation, estimates of effective population size, and immigration–emigration rates, Parramore and Revel islands serve as the major demographic source of raccoons on the northern islands, whereas Smith Island is the major source of raccoons on the southern islands. Most inferred movements of raccoons occurred among adjacent groups of islands that are interconnected by marsh and relatively shallow, narrow, open-water channels. These genetic results are consistent with our empirical studies of raccoon movement and support predictions from a cost-distance model of raccoon movement, which assumes that gene flow is primarily constrained by a combination of spatial distance and landscape resistance. Our landscape genetic analyses indicated that: 1) raccoons occur in a series of semi-independent local populations that exhibit significant genetic structure and are characterized by historical and ongoing colonization events, 2) island populations exhibit evidence of source–sink dynamics in patterns of variation in genetic diversity, effective population size, and emigration–immigration rates, 3) the Delmarva Peninsula mainland is not a major source of raccoons dispersing to most of the islands, and 4) individuals dispersed mostly among nearby islands and along least-cost pathways of landscape resistance, in agreement with predictions based on cost-distance models of raccoon movement in this system.

The American pika (Ochotona princeps) is a small, winter-active mammal inhabiting alpine environments. For alpine mammals, metabolic heat production and cellular mechanisms to cope with hypoxia are critical for survival and reproduction. Thus, because of the pikas' long association with alpine environments, they may have genetically adapted to alpine conditions. Here, we present evidence for positive selection acting at 2 loci within the Ochotona genome. These loci were identified by first assembling a list of 50 candidate genes and collecting sequence data from 2 O. princeps draft genomes available from public databases. We then tested the possibility that positive selection acted on the Ochotona lineage, relative to other mammalian species, using the CODEML program in the PAML package. These analyses indicated positive selection at 4 loci—insulin-like growth factor 1 gene (IGF-1), enoyl-CoA hydratase/3-hydroxyacyl CoA dehydrogenase (EHHADH), inducible nitric oxide synthase 2 (NOS2), and transforming growth factor beta 1 gene (TGF-β1). To test this assumption further, we collected DNA sequence data from the 4 genes of interest from multiple O. princeps individuals across a broad geographic range, as well as individuals from the congeneric collared pika (O. collaris). We used multiple interspecific and intraspecific polymorphism-based tests to test the resulting sequence data for patterns of non-neutral evolution. These tests provide additional support for positive selection acting on the IGF-1 and EHHADH loci.

Long-term studies from undisturbed forests provide a baseline by which to assess impacts of human activities, including climate change, on vertebrate population dynamics in lowland tropical forests. We use cameratrap data from January to March, 2005 to 2015, to examine patterns of variation in numbers of images and occupancy (proportion of cameras where images of a species were obtained), variables that may reflect changes in abundance or activity patterns of terrestrial mammals and birds in an undisturbed lowland forest of eastern Ecuador. We accumulated 1,961 independent records of 31 mammal species and 427 images of 17 bird species during 5,547 trap-days. Number of mammal species ranged from 15 to 25 per year (107 to 466 images), whereas birds ranged from 3 to 11 species per year (10 to 122 images). Capture rates varied both among species and among years but showed no evidence of declines; populations of several species appeared to increase (Priodontes maximus, Dasypus novemcinctus, Pecari tajacu, and Dasyprocta fuliginosa). Similarly, occupancy rates provided no indication of consistent declines; occupancy rates increased significantly for D. fuliginosa, D. novemcinctus, and P. maximus. There was no indication that variation in either capture rates or occupancy was related to variation in large-scale climate trends as represented by the Southern Oscillation Index. Results suggest that populations of most species that are well sampled by camera traps have remained relatively stable over 11 years. Long-term studies from other regions in the tropics are needed to evaluate the generality of this pattern.

Dromiciops gliroides is an arboreal marsupial endemic to the southern temperate forest located between 36°S and 43°S in both Chile and Argentina. This species is a key seed disperser of many native plants, including the keystone mistletoe, Tristerix corymbosus. We studied the population fluctuation of D. gliroides and the possible effects of natural disturbances on the population. We estimated density, abundance, survival, and recruitment ratios for 7 years (2009–2011 and 2013–2016) at Reserva Llao Llao, Argentina, using capture–recapture techniques. A Jolly–Seber model with robust design was fitted using a hierarchical Bayesian approach. The estimated mean abundance during these 7 years was 81 individuals. The highest abundances were observed in 2009, 2010, 2011, and 2014 (98 individuals on average). The years with lowest abundance were 2013, 2015, and 2016 (60 individuals on average), which coincided with the occurrence of natural disturbances in the study area (eruption of the Puyehue-Cordón Caulle volcano, the flowering of Chusquea bamboo and a subsequent rodent outbreak, and an unusually dry summer). These results suggest that the observed population fluctuations of D. gliroides could be related to natural forest disturbances.

Mineral micronutrients are critical for basic physiological function, and variable availability of minerals over the landscape can influence foraging decisions. Sodium is essential for nerve function and osmotic balance; however, it can be limiting in some environments, such as those at high elevations. Koalas (Phascolarctos cinereus) living in subalpine regions have been observed eating Eucalyptus mannifera bark, an unusual food choice for a folivore. We hypothesized that sodium may be deficient in leaves at high-elevation sites, and that the bark from trees could be a potential sodium source. We compared the mineral content of eucalypt bark and leaves in 3 areas where koalas chew bark and in leaves of a preferred food tree of koalas, E. viminalis, across a range of elevations. Individual chewed trees were rare compared to non-chewed conspecifics and patchily distributed. Bark from chewed E. mannifera trees had significantly higher concentrations of sodium than plant parts from non-chewed neighboring conspecifics and other Eucalyptus species trees. We also found that E. viminalis foliage had significantly less sodium at higher elevations than lowland populations. We propose that koalas have developed the unusual bark-eating behavior to meet sodium requirements in an otherwise sodium-poor landscape. Given the physiological importance of sodium, behavioral adaptations such as these may be critical to the ability of mammalian herbivores to survive in nutrient-deficient landscapes.

Specialist species are defined by their restricted range of tolerated environmental conditions and required resources. For example, in the New World leaf-nosed bats (Phyllostomidae), specialization in diet has been linked to morphological and behavioral innovations (i.e., skull form, foraging behaviors) that facilitate the occupation of new ecological niches by these animals. Here, we use the Honduran white bat, Ectophylla alba, as a model to test the behavioral responses of the species to a narrow diet: one based on figs of Ficus colubrinae (Moraceae). Through the use of radiotelemetry, we demonstrate that the foraging behavior of these bats is highly dependent on their main food resource. In response, behavioral adaptations have evolved to optimize the bats' foraging strategies and—at a broad level—the performance and survival of the species in their habitat. Conservation decisions should consider the tight linkage that exists among some species and their habitat characteristics or food resources (as demonstrated herein), in order to protect highly susceptible and unique species that could potentially go extinct with the disturbance or removal of specific features of their ecological interactions.

Play is a characteristic behavior of mammals, occurring among juveniles across a wide range of mammalian species. We evaluated the hypothesis that play helps prepare young animals to cope with unfamiliar situations. We observed play behavior in juvenile Belding's ground squirrels (Urocitellus beldingi) during the developmental period in which play primarily occurs in this species, and conducted behavioral tests in unfamiliar arenas at the beginning and toward the end of the play interval. Measures of social but not nonsocial play were associated with the outcomes of behavioral tests. Rates of social play and the duration of social play bouts were reliable predictors of increases in boldness and exploration across behavioral tests, as well as decreases in the time required to escape from an unfamiliar arena. In particular, juveniles who engaged in social play at intermediate to high rates and who had intermediate to long-lasting social play bouts had greater increases in boldness–exploration scores and greater decreases in escape times in behavioral tests than did juveniles who engaged in social play at the lowest rates and had the shortest social play bouts. These results support the idea that social play behavior in juvenile U. beldingi helps prepare juvenile squirrels to successfully navigate challenges during the juvenile period, and raise the possibility that minimum thresholds of social play may be sufficient for juvenile U. beldingi to gain some of the potential benefits of play behavior.

Animal research guidelines emphasize the need for researchers to be able to euthanize animals when required. Some field biologists rarely encounter the need to euthanatize animals, so may not develop competence or feel confident in the use of physical means. At the same time, there are increasing restrictions on the types of drugs that can be used in the field, and veterinary assistance may be far away should it be needed. For these situations, there is a pressing need for a transportable and reliable method of euthanizing animals. The use of CO₂ has been recommended for euthanasia for a variety of taxa so a small and lightweight euthanasia device was developed using a mini-regulator and a pre-set outlet tap to deliver CO₂ at rates suitable to comply with veterinary guidelines. The device and the necessary CO₂ cartridges can easily be stored and transported in a small container that can also act as the receiving chamber.