A new species of African wood mouse (Hylomyscus) is described from the western Kenya region. Previous studies have hypothesized that populations of Hylomyscus from this region may be assignable to either H. vulcanorum or H. cf. anselli. We compared 3 populations of Hylomyscus from western Kenyan montane forests to sister taxa from the Hylomyscus denniae group on the basis of morphology, morphometrics, mitochondrial DNA gene trees, multilocus species trees, and coalescent-based species delimitation to clarify relationships within these clades. Our results were congruent across data sets in support of this new species as sister to H. anselli and reproductively isolated from H. endorobae on the Mau Escarpment of Kenya where the 2 taxa are sympatric and syntopic. Lineages within the H. anselli group differ by 3.2–7.4% in (corrected) cytochrome-b sequences. Phylogeographic analysis of Hylomyscus n. sp. suggests strong population or range expansion, or both, since the last glacial maxima. A dated multilocus species tree places divergence of Hylomyscus n. sp. from H. anselli during the middle Pleistocene and the H. anselli group from the H. denniae group during the late Miocene to early Pliocene. This species is known from protected sites on Mt. Elgon, as well as unprotected sites within the Mau Escarpment and Cherangani Hills where extensive human habitat disturbance warrants conservation attention.

Javelinas (Pecari tajacu) are expanding their range northward in the southwestern United States, but little is known of habitat relationships in northern populations. We used occupancy modeling and maximum entropy modeling of data collected from a camera-trapping grid to investigate javelina occupancy and identify habitat correlates associated with presence in the southern San Andres Mountains of south-central New Mexico. Corrected for incomplete detection, occupancy increased from 0.036 (SE = 0.035) in 2007 to 0.327 (SE = 0.082) by 2011. Presence of javelinas was most strongly associated with areas in close proximity to permanent water sources; with overstory or high shrub canopies of riparian, oak–mountain mahogany, or pinyon–juniper; and with low (< 6%) slopes. Areas with P > 0.75 for javelina presence comprised only 6.7% of the San Andres landscape. Circadian patterns of behavior indicated that javelinas were primarily diurnal during colder months and nocturnal during warmer months. Expansion of javelina occupancy may be related to a slight trend in increasing minimum winter temperatures, because severe winters were hypothesized to limit the northern distribution of javelinas. Additionally, javelinas appear dependent upon a tree or shrub overstory, ideally associated with riparian corridors, to mitigate heat stress associated with occupancy of Chihuahuan Desert habitats.

The Great Basin pocket mouse, Perognathus parvus, inhabits temperate shrub-steppe and arid grassland biomes throughout the Columbia Plateau, Great Basin, and adjacent regions of western North America. We used both mitochondrial DNA (mtDNA) and nuclear DNA (nDNA) sequences to address phylogenetic and biogeographic structure within the P. parvus species group. Phylogenetic and biogeographic analyses divide haplotypes from the mtDNA cytochrome oxidase subunit 3 (COIII) gene into largely allopatric northern versus southern lineages (clades), with divergences of up to 18.8%. The southern mtDNA clade also includes at least 1 of the 2 recently extant populations of the white-eared pocket mouse, P. alticolus—an endangered species with a restricted range in southern California. The northern mtDNA clade is further subdivided into several additional lineages with divergences as high as 8.8%, whereas the southern clade has no divergence greater than 1.2%. The deeper mtDNA gene tree structure was recovered by use of nDNA exon sequences from the interphotoreceptor retinoid-binding protein (IRBP) and recombination activating gene 2 (RAG2) gene regions, supporting a “gene tree–species tree” congruence. We estimated through molecular clock analyses that the northern and southern clades likely diverged within a late Miocene time frame. The limited available karyological evidence is consistent with a genome-wide divergence between northern and southern clades—thus, is consistent with recognition of each as a separate species. Conversely, our morphometric analysis revealed a high level of morphological conservatism without detectable diagnostic differences, rendering them as “cryptic” species. We revised species-level taxonomy, designating 2 neotypes given apparent loss of original type specimens. We postulate that barriers associated with Columbia Plateau, Snake River Plain, and Great Basin physiographic evolution, during a Neogene time frame, resulted in persistent geographic isolation driving divergence between the northern and southern clades.

Handleyomys chapmani (Chapman's Handley's mouse) is a Mexican endemic rodent inhabiting humid montane forest of the Sierra Madre Oriental (SMO), the Oaxacan Highlands (OH), and the Sierra Madre del Sur (SMS). The systematic status of populations currently classified as H. chapmani has been problematic and to date evolutionary relationships among populations remain unresolved. In this study we use sequences from the mitochondrial cytochrome-b gene (1,143 base pairs [bp]) and intron 7 of the beta fibrinogen gene (621 bp) to reconstruct a phylogeny, estimate divergence times, and assess patterns of sequence variation over geography among samples of H. chapmani. This species was recovered as 2 monophyletic clades corresponding to the SMO-OH and SMS mountain ranges. Moreover, H. saturatior, the purported sister taxon to H. chapmani, was consistently recovered as the sister lineage to the SMO-OH clade, rendering H. chapmani paraphyletic. The geographic distribution of the 2 H. chapmani clades and of H. saturatior strongly correlate with the geographic extent of the SMO-OH, SMS, and the Trans-Isthmian Highlands (highlands east of the Isthmus of Tehuantepec through Central America) mountain ranges. Divergence times associate their isolation to late Pleistocene climatic changes that likely were reinforced by barriers such as the Isthmus of Tehuantepec, the Tehuacán–Cuicatlán Valley, and the Central Valleys of Oaxaca. The fact that populations of H. chapmani represent 2 independent evolutionary lineages results in a substantial reduction in the distributional range for both entities. Therefore, the conservation status of H. chapmani should be re-evaluated.

Handleyomys chapmani (ratón de Handley de Chapman) es un roedor endémico de México con distribución en la Sierra Madre Oriental (SMO), Sierra Norte de Oaxaca (OH) y Sierra Madre del Sur (SMS). El estatus taxonómico de las poblaciones actualmente clasificadas como H. chapmani ha sido problemático y hasta la fecha, las relaciones evolutivas entre dichas poblaciones continúan sin resolverse. En este estudio, usamos secuencias del gen mitocondrial citocromo b (1143pb) y del intron 7 del gen beta fibrina (621pb) para estimar una filogenia del grupo, tiempos de divergencia y analizar los patrones de variación genética entre poblaciones de H. chapmani en un sentido geográfico. H. chapmani fue recuperado en 2 clados monofiléticos correspondientes a los sistemas montañosos de la SMO-OH y SMS. Además, H. saturatior (ratón de Handley de bosque nublado), reconocido como el grupo hermano de H. chapmani, fue consistentemente recuperado como el linaje hermano al clado de las SMO-OH; revelando a H. chapmani como un taxón parafilético. La distribución geográfica de los 2 clados en H. chapmani y H. saturatior muestra una fuerte correlación con la extensión geográfica de la SMO-OH, la SMS y las Tierras Altas Trans-Istmicas (TIH; tierras altas al este del Istmo de Tehuantepec en Chiapas y América Central). Los tiempos de divergencia asocian el aislamiento de éstas entidades con cambios climáticos del Pleistoceno superior, que posiblemente fue reforzado por barreras geográficas como el Istmo de Tehuantepec, el Valle Tehuacán-Cuicatlán y los Valles Centrales de Oaxaca. El hecho de que las poblaciones de H. chapmani constituyan 2 entidades evolutivas, tiene como consecuencia la reducción significativa del rango de distribución de estos 2 linajes. Por lo tanto, el estatus de conservación de H. chapmani debe ser reevaluado.

After centuries of population decline and range contraction, gray wolves (Canis lupus) are now expanding in Europe. Understanding wolf social structure and population dynamics and predicting their future range expansion is mandatory to design sound conservation strategies, but field monitoring methods are difficult or exceedingly expensive. Noninvasive genetic sampling offers unique opportunities for the reliable monitoring of wolf populations. We conducted a 9-year-long monitoring program in a large area (approximately 19,171 km²) in northern Italy, aiming to identify individuals, estimate kinship, reconstruct packs, and describe their dynamics. Of 5,065 biological samples (99% scats), we genotyped and sexed 44% reliably using 12 unlinked autosomal microsatellites, 4 Y-linked microsatellites, and a diagnostic mitochondrial DNA control-region sequence. We identified 414 wolves, 88 dogs, and 16 wolf × dog hybrids. Wolves in the study area belonged to at least 42 packs. We reconstructed the genealogy of 26 packs. The mean pack size was 5.6 ± 2.4 SD, including adoptees, with a mean minimum pack home range of 74 km² ± 52 SD. We detected turnovers of breeding pairs in 19% of the packs. Reproductive wolves were unrelated and unrelated dispersers founded new packs, except for 1 pack founded by a brother–sister pair. We did not detect multiple breeding females in any packs. Overall, the population was not inbred. We found significant isolation by distance and spatial autocorrelation, with nonrandom genetic structure up to a distance of approximately 17 km. We detected 37 dispersers, 14 of which became breeders in new or already existing packs. Our results can be used to model habitat use by wolves, to estimate survival rates, to predict future expansion of the wolf population, and to build risk maps of wolf–human conflicts.

A new living species of the desert-adapted tetraploid rodent Tympanoctomys (Caviomorpha, Octodontidae) is described. The new form is restricted to the type locality in Chubut Province, central Patagonia, Argentina, although is known from at least 4 additional Holocene-aged localities along the middle and lower valley of the Chubut River. Tympanoctomys sp. nov. is smaller than the living T. barrerae, its general coloration is yellowish (reddish in T. barrerae) and its tail is equal to ∼43–50% of head and body length (∼49–53% in T. barrerae). Its skull and dentition are characterized by a unique combination of morphological traits, including narrow and posteriorly acuminate nasals (broad and barrel-shaped in T. barrerae), supraoccipital not laterally expanded (expanded in T. barrerae), and 8-shaped lower 3rd molar (comma-shaped in T. barrerae and †T. cordubensis). Morphometric and genetic evidence supports the specific distinction of this Patagonian endemic Tympanoctomys, also characterized by smaller sperm than T. barrerae. The reduced range of the new species, coupled with its recent extinction from the Chubut River valley and the potential impact of large uranium mining projects in central Patagonia, suggest that this species faces a severe extinction risk in the short term.

Se describe una nueva especie viviente del roedor tetraploide desertícola Tympanoctomys (Caviomorpha, Octodontidae). La nueva forma está restringida a su localidad tipo en la provincia del Chubut, Patagonia central, Argentina, si bien es conocida al menos de 4 localidades de edad Holoceno a lo largo del valle medio e inferior del río Chubut. Tympanoctomys sp. nov. es más pequeña que la viviente T. barrerae; su coloración general es amarillenta (rojiza en T. barrerae) y su cola es relativamente más corta (∼43–50% de la longitud cabeza–cuerpo versus ∼49–53% en T. barrerae); su cráneo y dentición están caracterizados por una combinación única de rasgos morfológicos, incluyendo nasales estrechos y posteriormente acuminados (anchos y con forma de barril en T. barrerae), supraoccipital no expandido lateralmente (expandido en T. barrerae) y tercer molar inferior en forma de 8 (en forma de coma en T. barrerae y †T. cordubensis). Diferencias morfométricas y genéticas robustecen la distinción específica de este Tympanoctomys patagónico endémico, también caracterizado por espermatozoides más pequeños que los de T. barrerae. Su reducido rango de distribución, en conjunción con su extinción reciente en el curso medio e inferior del río Chubut y el potencial impacto de extensivos proyectos mineros en Patagonia central sugieren que esta especie enfrenta un riesgo severo de extinción en el corto plazo.

Mammalian habitat specialists are suffering notable population declines and localized extinctions in response to climate change. Plastic behavioral responses, especially in foraging, may be critical for specialists to tolerate changes in temperature, precipitation, and resource availability. Here, we investigate the foraging behavior of a mammalian alpine specialist living in atypical habitat. American pikas (Ochotona princeps) are typically limited to high elevations in western North America; however, they persist near sea level in the Columbia River Gorge, well outside their previously assumed climatic niche. We hypothesized that utilizing unusual food resources contributes to pika persistence in this unusual climate. Moss comprised more than 60% of the diet at 2 sites, more than observed for any mammalian herbivore in the wild. Moss is available year-round in this habitat; thus, by specializing on moss, pikas do not have to construct large food caches to survive winter. These results suggest a larger degree of behavioral and dietary plasticity than previously assumed for this species. Understanding a species' capacity to adapt its foraging strategies to new resource landscapes will be essential to assessing its vulnerability to future climate change and to developing conservation plans.

Extreme weather variation on the northern Great Plains of North America can potentially influence the abundance of grassland rodents across vast areas. We used the remains of 33,697 small mammals collected from owl pellets in central and western Canada over 15 years to determine the influence of weather on the annual abundance of deer mice (Peromyscus maniculatus), sagebrush voles (Lemmiscus curtatus), and meadow voles (Microtus pennsylvanicus). Weather variation affected the annual abundances of all 3 species; however, influence on deer mouse and sagebrush vole annual abundances was relatively small compared to that on meadow voles. This finding may indicate that factors other than weather (i.e., habitat availability) are more important for the abundance of deer mice and sagebrush voles at the landscape scale. In contrast, meadow voles were positively associated with the duration of snow cover above the hiemal threshold (20 cm), exhibiting up to 5-fold increases (i.e., irruptions) in abundance following winters of persistent, deep snow cover. Our study is the first to examine the effects of weather on landscape-scale abundance of rodent species on the northern Great Plains of North America, providing further insight into the role weather plays in driving rodent population fluctuations in this highly seasonal environment.

The evolution of sociality across octodontid rodents remains puzzling. Although basal species are solitary living, the most derived octodontids studied so far are social, implying that sociality evolved recently from solitary-living ancestors. However, the social behavior of some octodontids remains anecdotal. We aimed to provide the 1st systematic data on activity, space use, and social behavior of the moon-toothed degu (Octodon lunatus), a derived octodontid rodent. We used livetrapping and radiotelemetry to monitor patterns of aboveground activity, aboveground range areas and overlap, and use of resting locations in a coastal population in north-central Chile. Activity of O. lunatus was statistically similar during nighttime and daytime, implying no clear diurnal or nocturnal activity. During daytime the animals used resting locations that were associated with high shrub cover and Pouteria splendens. Radiocollared males and females shared resting locations on multiple occasions. There was a nonsignificant trend in degus that used same resting locations to exhibit greater range overlap than degus using different resting locations. Associations based on resting locations revealed a total of 5 social groups. Taken together, these results indicate that adult O. lunatus exhibit some sociality, a finding consistent with a trend in which group living is more frequent in the most derived compared with basal octodontids.

Nuestro conocimiento sobre la evolución del comportamiento social en roedores octodóntidos es aún fragmentario. La información disponible indica que las especies filogenéticamente basales son solitarias, mientras que las más derivadas tienden a ser sociales. Sin embargo, la información sobre la estructura social disponible para varias especies es anecdótica, lo cual dificulta el establecimiento de conclusiones robustas sobre la evolución del comportamiento social en este clado. Este es el primer estudio que cuantifica la actividad, uso del espacio, y comportamiento social del degú costino (Octodon lunatus), una especie derivada de octodóntido. Durante noviembre y diciembre de 2010 y 2011 se utilizaron métodos de captura–recaptura y telemetría para cuantificar el patrón diario de actividad superficial, ámbitos de hogar, solapamientos entre ámbitos de hogar, y uso compartido de parches de descanso y nidificación en una población costera localizada en el centro-norte de Chile. La actividad de O. lunatus, medida como desplazamientos individuales entre localizaciones consecutivas, mostró una tendencia estadísticamente no significativa a ser mayor en horas de la noche. Durante el día los animales usaron 1 a 3 sitios de descanso y anidamiento asociados con una alta cobertura arbustiva, donde Pouteria splendens (lúcumo) fue la especie dominante. Machos y hembras compartieron estos sitios de descanso en múltiples ocasiones. El solapamiento entre los ámbitos de hogar tendió a ser mayor en animales que además compartieron sitios de descanso comparado con animales que no compartieron estos sitios. En base al uso compartido de refugios se identificó 1 grupo social en 2010 y 4 grupos en 2011. La composición de estos grupos fue de 1 a 3 hembras adultas y de 1 a 2 machos adultos (2 a 4 adultos en total). Globalmente, los resultados indicaron que O. lunatus muestra algún grado de sociabilidad, observación que apoya una tendencia en la cual el comportamiento social es más frecuente en especies filogenéticamente derivadas de octodóntidos.

Biodiversity patterns are the result of the interaction of numerous contemporary factors and historical opportunities for allopatric speciation. Several hypotheses regarding climatic features and topographic characteristics have been reported as determinants of species richness along elevation gradients. However, how these factors interact to shape small mammal species richness along the dry Andes ecosystem is not well understood. The objectives of this paper were to analyze patterns of species diversity along the central dry Andes, and to evaluate how climatic and topographic factors explain diversity patterns. Our results showed a positive and monotonic relationship between small mammal species richness and altitude, whereas abundance patterns showed a midelevation peak. Climate and topography were the most important predictor variables explaining small mammal species richness and abundance patterns in the Andes. This study underlines the role of the Andes in promoting and sustaining biodiversity, as well as the need to encourage conservation planning in mountain ecosystems.

Los patrones de biodiversidad son el resultado de la interacción entre numerosos factores contemporáneos y eventos históricos que propician la especiación alopátrica. Numerosos factores climáticos y topográficos han sido mencionados como determinantes para los patrones altitudinales de riqueza de especies. Sin embargo es poco conocido aún como estos factores interactúan para modelar la riqueza de especies a lo largo de la Cordillera de los Andes. Los objetivos de este trabajo fueron analizar los patrones de diversidad de especies a lo largo de los Andes templados, y evaluar como los factores climáticos y topográficos explican los patrones de riqueza y abundancia de especies. Nuestros resultados muestran una relación monotónica y positiva entre riqueza de especies y altura. Mientras el patrón de abundancia es unimodal. Para ambos patrones el clima y la topografía son las variables predictoras más importantes. Este estudio resalta el rol de los Andes en promover y sostener la biodiversidad, y acentúa la necesidad de fomentar planes de conservación en ecosistemas montanos.

White-footed mouse (Peromyscus leucopus) consumption of plant fruits can significantly affect vegetative community structure. However, little is known about the effects of relative selection between different fruit species on the establishment and spread of invasive shrubs. Depending on foraging activity, white-footed mice may provide resistance against exotic establishment, have no impact, or even contribute to invasive spread. Selection of invasive Morrow's honeysuckle (Lonicera morrowii) and 5 native soft-mast species was studied across 3 cover types (forest, field, and edge) and 2 seasons in southwestern Pennsylvania. Foraging stations, containing equal quantities of each species, were randomly placed in each of the cover types. In addition, nutrient composition and total energy were measured. Fruit consumption was nonrandom based on compositional analysis (P < 0.05). Honeysuckle was consumed over native staghorn sumac (Rhus typhina); otherwise, it was consumed less than all natives. Honeysuckle fruits had significantly less lipids (0.67%) than all natives (P < 0.05), and one of the lowest protein contents (0.66%). Total energy was important in distinguishing the highest selected fruits: black cherry (Prunus serotina; 0.45 kcal) and common dewberry (Rubus flagellaris; 0.36 kcal). Selection of high-nutrient native fruits over those of honeysuckle may confer additional competitive advantages to the seeds of this invasive shrub. In this way, white-footed mice may contribute to the establishment of Morrow's honeysuckle in multiple cover types.

Power laws describe the functional relationship between 2 quantities, such as the frequency of a group as the multiplicative power of group size. We examined whether the annual size of well-surveyed wintering populations of endangered Indiana bats (Myotis sodalis) followed a power law, and then leveraged this relationship to predict whether the aggregation of Indiana bats in winter was influenced by global climate processes. We determined that Indiana bat wintering populations were distributed according to a power law (mean scaling coefficient α = −0.44 [95% confidence interval {95% CI} = −0.61, −0.28). The antilog of these annual scaling coefficients ranged between 0.67 and 0.81, coincident with the three-fourths power found in many other biological phenomena. We associated temporal patterns in the annual (1983–2011) scaling coefficient with the North Atlantic Oscillation (NAO) index in August (β_NAOAugust = −0.017 [90% CI = −0.032, −0.002]), when Indiana bats are deciding when and where to hibernate. After accounting for the strong effect of philopatry to habitual wintering locations, Indiana bats aggregated in larger wintering populations during periods of severe winter and in smaller populations in milder winters. The association with August values of the NAO indicates that bats anticipate future winter weather conditions when deciding where to roost, a heretofore unrecognized role for prehibernation swarming behavior. Future research is needed to understand whether the three-fourths–scaling patterns we observed are related to scaling in metabolism.

Communication in solitary and social mustelids has been mainly studied in terms of olfactory abilities. However, most otters appear highly social and vocal, but little is known about the role of vocal signals in communication in those species. An analysis of the airborne vocal repertoire and social networks of Asian small-clawed otters (Aonyx cinerea) is reported herein. The vocal repertoire of a captive group of 10 individuals was composed of 4 context-dependent vocalization units, which were emitted alone, repeated, or combined in a nonrandom way, resulting in 7 vocalization types. Individuals varied in their preference to use certain vocalization types and to maintain bonds with some particular group members. Older, larger, and heavier otters produced lower-frequency sounds. Thus, Asian small-clawed otters are clearly social and possess a high potential for vocal communication, such as acoustic coding of messages about ongoing social activities and biologically important characteristics about the sender. Future comparative studies of mustelids will tell whether solitary species may use essentially olfactory communication, whereas social species use multimodal communication, including vocal cues.

Eurasian otters (Lutra lutra) have been described in the literature as solitary, with the 2 sexes interacting only during mating. Data on otter sociality are rather scant, however, especially in Mediterranean regions, and the group formation documented in temperate zones has suggested some social plasticity. We investigated the sociospatial organization of a Mediterranean population of Eurasian otters by analyzing static and dynamic interactions among 15 individuals radiotracked during 3.5 years in Alentejo (southern Portugal). Contrary to what is described in the literature and expected for solitary animals, otter dyads showed positive interactions, with individuals associating more often than expected by chance. Moreover, otter movement patterns were correlated. Finally, otters shared diurnal resting sites more often than expected. Adult males and females with cubs overlapped spatially and temporally, even sharing resting sites when the males had no paternity. Nonrelated otter dyads of opposite sex overlapped home ranges and core areas. Ranges of males overlapped with those of 1–3 females, whereas dyads of the same sex exhibited almost no overlap, confirming the classic mustelid intrasexual territoriality and a polygynous mating system (nevertheless, suspicions of female polyandry arose). On average, overlap of home ranges was higher than that of home-range cores. Our results contradict several statements in the literature on European otter sociality and reproductive behavior. We conclude that Eurasian otters are more social than previously thought, adding further evidence that social behavior in solitary carnivores may reveal significant flexibility.

Stable carbon (¹³C/¹²C; δ¹³C) and nitrogen (¹⁵N/¹⁴N; δ¹⁵N) isotope ratios are best used to assess wild animal diets when the isotopic differences between consumers and diets are known. These differences are called discrimination factors (expressed with Δ notation). We report the 1st Δ¹³C and Δ¹⁵N values between diet and fur from captive individuals held on controlled diets for 7 months and representing 4 felid species: African lions (Panthera leo), bobcats (Lynx rufus), Canada lynx (Lynx canadensis), and mountain lions (Puma concolor). All animals were fed a mix of diet items (beef, beef rib, a commercial carnivore diet, chicken, mice, rats, turkey, and turkey wings) that was consistent throughout their molting period. Weekly diet composition was determined by the percentage of mass of each diet item and overall δ¹³C and δ¹⁵N values were calculated for each animal's diet. The mean Δ¹³C and Δ¹⁵N values (± SD) between felid fur and their non–lipid-extracted diets were 1.1‰ ± 0.2‰ and 3.5‰ ± 0.0‰, respectively (African lion, n = 1 animal sampled at 2 intervals); 5.5‰ ± 0.5‰ and 4.1‰ ± 0.1‰, respectively (bobcats, n = 3); 2.4‰ and 3.3‰, respectively (Canada lynx, n = 1); and 4.7‰ ± 0.6‰ and 4.5‰ ± 0.2‰, respectively (mountain lions, n = 2). Variations in Δ¹³C and Δ¹⁵N values among species were likely due to dietary differences and we recommend the use of the Δ¹³C (5.5 ± 0.5) and Δ¹⁵N (4.1 ± 0.1) values obtained from the bobcats for future determinations of wild felid foraging ecology as they were held on diets composed of 100% whole animals and animal parts, which best reflects diets of wild felids.

Many animals consume mixed diets that maximize their fitness by optimizing macronutrient intake. We tested whether brown bears (Ursus arctos), generalist omnivores that hibernate, regulated their diet to a common nutrient target, achieved a nutrient target related to fitness, and selected a nutrient target that differed between seasons and from other species with differing life histories. When given unlimited access to 2 or 3 highly digestible foods containing primarily protein, carbohydrate, or lipid, brown bears selected mixed diets in which protein provided 17% ± 4% SD of the metabolizable energy and 22% ± 6% of the dry matter. This dietary protein content maximized the rate of gain per unit of energy consumed, is similar to the level preferred by other omnivores, and is less than that preferred by obligate carnivores. Between seasons, bears selected similar dietary protein levels, although the proportion of lipid was higher during the fall than during the spring. Bears strongly preferred lipids over carbohydrates, as did other carnivores, but they used lipids and carbohydrates with equal efficiency to produce a dietary protein content that maximized mass gain per unit of energy intake. Thus, dietary sources of lipids and carbohydrates play an interchangeable and important role in determining the productivity of bears that goes beyond their role in providing energy.

The sperm whale (Physeter macrocephalus) clan is a social unit that shares a similar repertoire of vocalizations called codas. Coda repertoires and clan structure are well studied in sperm whales of the eastern tropical Pacific, but information is limited in the western North Pacific. We compared sperm whale codas recorded from female and immature sperm whales in 2 areas near Japan, off the Kumano Coast and off the Ogasawara Islands, to determine whether different clans exist in these waters. Repertoires of coda types were different between the 2 areas, and the lengths of codas consisting of the same number of clicks were longer in duration near Kumano than near Ogasawara. Our results suggest that different vocal clans inhabit in these 2 areas. Such clear geographic structure of clans is not known in other waters in the Pacific and distinct environmental features may favor a clan in which members share a specific foraging strategy and coda repertoire, both of which likely are transmitted through social learning.

Historically, specimens representing the Peromyscus boylii species group (from montane regions of western and southwestern Mexico) have been referred to as P. boylii or P. levipes. However, previous studies indicated that specimens from eastern Nayarit possessed a karyotype and mitochondrial DNA haplotype distinct from other members of the P. boylii species group. Together, these data precluded an assignment of these specimens to any currently recognized taxon in the P. boylii species group. Availability of additional specimens from this region provided an opportunity to reevaluate the taxonomic status of this complex. Analyses of 18 morphological characters demonstrated that specimens from eastern Nayarit possessed a significantly longer length of the nasals relative to the other species. Further, phylogenetic analyses (parsimony and likelihood) of DNA sequences obtained from the mitochondrial cytochrome-b gene indicate these specimens form a monophyletic clade embedded within a strongly supported clade containing representatives of P. beatae, P. levipes, and P. schmidlyi. Together, these results indicated that specimens from the Sierra Madre Occidental region of Nayarit represent an undescribed species of Peromyscus.

Históricamente, los especímenes que representan al grupo de especies de Peromyscus boylii (de regiones montanas del oeste y suroeste de México) han sido identificadas como P. boylii o P. levipes. Sin embargo, estudios previos han indicado que los especímenes del este de Nayarit poseen un cariotipo y un haplotipo del ADN mitocondrial distinto al de otros miembros del grupo de especies de P. boylii. Juntos, estos datos excluyen la asignación de dichos especímenes a cualquier taxón actualmente reconocido en el grupo de especies de P. boylii. La disponibilidad de muestras adicionales de esta región permitió reevaluar la taxonomía de este complejo. El análisis de 18 caracteres morfológicos demostró que los especímenes procedentes del este de Nayarit poseen una longitud significativamente mayor del hueso nasal en relación a otras especies de este complejo. Además, análisis filogenéticos (parsimonia y verosimilitud) de secuencias de ADN obtenidas del gen mitocondrial citocromo-b indican que estos especímenes forman un clado monofilético embebido dentro de otro clado que, con fuerte apoyo estadístico, contiene a representantes de P. beatae, P. levipes, y P. schmidlyi. En conjunto, todos estos resultados indican que los especímenes de la región de Sierra Madre Occidental de Nayarit representan una especie no descrita de Peromyscus.