Large mammals often play critical roles within ecosystems by affecting either prey populations or the structure and species composition of surrounding vegetation. However, large mammals are highly vulnerable to extirpation by humans and consequently, severe contractions of species ranges result in intact large mammal faunas becoming increasingly rare. We compared historical (AD 1500) range maps of large mammals with their current distributions to determine which areas today retain complete assemblages of large mammals. We estimate that less than 21% of the earth's terrestrial surface still contains all of the large (>20 kg) mammals it once held, with the proportion varying between 68% in Australasia to only 1% in Indomalaya. Although the presence of large mammals offers no guarantee of the presence of all smaller animals, their absence represents an ecologically based measurement of human impacts on biodiversity. Given the ecological importance of large mammals and their vulnerability to extinction, better protection and extension of sites containing complete assemblages of large mammals is urgently needed.

Among the 19 currently recognized species of Sminthopsis, differences in the morphology of the free portion of the penis can be seen in the tip, which may be bifid, blunt, knoblike, or have a terminal median process, and which may have a subterminal skin fold; and the urethral opening and terminal passage (urethral grooves or urethral chamber). The urethra may open dorsally or ventrally, and the urethral grooves may lie mesially or ventrally on the bifid portion of the tip. Ten forms can be recognized and interspecific affinities based on penis morphology have been examined for congruence with species groupings based on other independent character sets including external, cranial, and dental characters and molecular data. Penis forms showed the greatest congruence with phylogenetic groups delineated by molecular data.

A new species of Barbastella is described, originally discovered in 2001 in Beijing, northern China. The description of the new species is based on both morphological and molecular data. The morphology of the skull and ears of the new bat is more similar to that of the Egyptian barbastelle (B. leucomelas) and B. barbastellus distributed in Europe than to B. leucomelas found in southern China and Taiwan. Projections and notches occur along the posterior margin of each ear, and a small lobe (vaulted process) protrudes from the middle outer edge of each pinna. The skull and body size of the new species are larger than in B. leucomelas. Echolocation calls were of 2 types, a brief frequency-modulated call that was alternated with longer calls with a convex frequency–time course. The calls were very similar to those of B. barbastellus recorded in Europe, although they may be slightly lower in frequency. Molecular phylogenies were reconstructed from cytochrome-b (Cytb) and nicotinamide adenine dinucleotide dehydrogenase subunit 1 (ND1) gene sequences. Cladograms of ND1 indicated that barbastelles from the Beijing area form a monophyletic group, which is the sister to B. leucomelas from Egypt. The clade including the new species and Egyptian barbastelle clusters with B. barbastellus, but not with B. leucomelas from Sichuan, Taiwan, and Japan. The genetic distances (corrected Kimura 2-parameter) between Barbastella sp. nov. and most bats from other localities (including all B. barbastellus) were 14.31–17.69% at the ND1 gene and 15.01–17.36% at the Cytb gene. However, ND1 divergence is 12.79% between Barbastella sp. nov. and B. leucomelas from Egypt. All these results support the hypothesis that the barbastelle from Beijing is a new species. Additionally, because Egypt is the type locality of B. leucomelas, the paraphyletic nature of B. leucomelas suggests that barbastelles from Sichuan, Taiwan, and Japan—which are currently classified as B. leucomelas darjelingensis—should not be considered conspecific with B. leucomelas.

Clines of biological variation result from variation in physical environmental conditions. We report new reproductive data for a population of antelope ground squirrels, Ammospermophilus leucurus, at the northern geographic limit of this species. We then analyze reproductive patterns at 3 sites spanning the entire north–south extent of the geographic range, covering more than 2,500 km and 21 degrees of latitude. The overall breeding season of populations is relatively short in Oregon (42°N) and California (37°N), but in Baja California (24°N) it encompasses half a year. Mean litter size decreases significantly from north to south, from 9.3 (SD = 1.8) per litter in Oregon to 5.9 (SD = 1.5) in Baja California. Major shifts in seasonality of precipitation and ecosystem composition and diversity are associated with longer breeding season and lower litter size at the southern geographic extreme of A. leucurus. The environmental predictability for the northern populations is due to “constancy,” whereas the predictability at the southern extreme is due to “contingency.” The observed latitudinal reproductive patterns represent local responses of populations to environmental conditions and the related characteristics of North America's major desert ecosystems.

Many factors important to reproduction are difficult to quantify for wild mammals, yet an understanding of them is often critical to species' recovery programs, particularly those involving captive breeding and reintroduction. We examined management variables employed by the Vancouver Island marmot captive breeding program during 1998–2005 to determine how such variables influenced production of young and litter sizes. We then tested the ability of factors that were identified as important to predict production of young in the breeding program in 2006. For previously paired animals, production of young was significantly greater when they had been paired with the same mate for ≥1 year before the breeding season. When these females had been with a mate for <1 year, production of young was more than 2 times greater among 2–4 year olds compared to older age classes. Among previously paired females, 5–7 year olds and those that had produced young previously tended to produce young more often than other categories. Litter size was positively influenced by visual contact between a female and other pairs. For previously paired females, age, the amount of time paired with their mate, and previous production of young accurately predicted 75% of production of young in 2006. We propose that results from our study be combined with genetic considerations to plan future pairings in the breeding program and to assist in the selection of individuals for reintroduction to the wild. Methods reported herein may be applicable to recovery programs for other imperiled mammals.

Total parental expenditure of mammals and birds has been predicted to increase with litter or brood size, but data from rodents provide little support for this prediction. We examined the effects of natural variation in litter size on parental nest attendance in pine (= woodland), prairie, and meadow voles housed in seminatural environments. In all 3 species, mothers spent less time in the nest with large litters than with small; time spent in the nest by fathers was unaffected by litter size. We suggest that failure to meet the prediction of increased parental expenditure with increased litter size reflects basic differences in the manner in which mammals and birds feed altricial young.

Behavioral monogamy in mammals varies from male–female pairs that spend most of their time in close spatial contact (associated pair-living) to pairs that occupy exclusive territories but travel, forage, and sleep alone (dispersed pair-living). We present radiotelemetry data on 46 adult large treeshrews (Tupaia tana) from 2 populations in Sabah, Malaysia, that indicate that this species forms dispersed pairs across a range of ecological conditions. Dispersed pair-living was the primary behavioral mating system in primary forest during a major fruit masting event, in nonmasting primary forest, and in selectively logged forest with significantly higher fruitfall than in primary forest. Territories of behavioral partners were spatially concordant, but both male and female territories typically overlapped the boundaries of 1–3 extra-pair territories. Comparison between masting and nonmasting forests indicated that females exhibited better body condition during masting, whereas males exhibited larger home-range areas and longer daily movements. Both males and females exhibited better body condition in selectively logged versus primary forests, but ranging patterns were not significantly different between these habitats. We argue that intraspecific foraging competition is the most likely explanation for the evolution of dispersed pair-living in T. tana.

Social monogamy is characterized by long-term pair-bonds, but there is extensive variation among socially monogamous species in the timing of pair formation, the extent to which pair-mates associate throughout the year, the duration of pair-bonds, and the frequency with which pair-bonds are dissolved while both partners are living. We studied these aspects of social monogamy in kit foxes (Vulpes macrotis) at 1 urban and 2 nonurban sites. Behavior was similar across sites despite differences in ecological conditions. Pair formation occurred throughout the year, often within a month after the loss of a mate. Pair-mates associated throughout the year. Some pairs remained associated for more than 1 breeding season. Death of a pair-mate was the most common reason for the dissolution of a pair (14 of 16 cases). Two pairs dissolved while both partners were still living: 1 due to abandonment by a male of his pair-mate and territory and 1 due to displacement of a male by another male. These characteristics of social monogamy in kit foxes may be related to year-round territoriality, and may optimize individual fitness by enhancing survival and ultimately reproductive success.

We examined spectral features that characterize the highly stereotyped, repetitive vocalizations of New World baiomyine rodents. Although stereotyped vocal signaling, described as “song,” has been documented in Scotinomys (singing or brown mice), its occurrence was unknown in the sister taxon Baiomys (pygmy mice). We also recorded vocalizations of females, about which little information was previously available. Although examination of morphological and molecular data supports a close relationship between the 2 baiomyine genera, we identified song as a complex behavior that further underpins the monophyly of the Baiomyini. Both spectral and temporal features render these songs highly localizable, a characteristic of possible utility for courtship and other social behavior. The song of Baiomys is confined entirely to the ultrasonic spectrum, unlike that of Scotinomys, which uses a broader range of frequencies. The intensity, identity, and predictability of vocalization suggest that these songs are purposeful and carry information important for species identification.

In the Neotropics, bat-pollinated plants secrete relatively dilute nectars dominated by hexoses (glucose and fructose) with only small amounts of sucrose. We investigated the concentration and sugar composition preferences of Saussure's long-nosed bat (Leptonycteris curasoae) and the long-tongued bat (Glossophaga soricina) to test the hypothesis that bats prefer the predominant characteristics (sugar composition and concentration) found in their natural diets. We offered bats pairs of test diets in large outdoor enclosures that allowed free flying. We used artificial nectars that simulated compositions and concentrations found in flowers visited by these 2 species at the study site. Contrary to our predictions, bats showed no preference between sugar types when test solutions had the same concentration. However, L. curasoae preferred concentrated over dilute solutions independent of sugar type. Only 1 preference for concentrated over dilute solutions was recorded for G. soricina. Both species of bat appeared to perceive sugar types as energetically equivalent in most trials. Our study rejects the hypothesis that nectar-feeding neotropical bats act as a selective pressure on nectar composition in chiropterophilous plants. Other possible explanations for the predominance of hexose in chiropterophilous flowers need to be evaluated.

Changes in diet quality may be as important as changes in energy availability in the reproductive success of small mammals. The effect of dietary protein on fitness of females is most likely mediated by changes in yield or composition of milk. Mus musculus was used as a model to test whether dietary protein restriction leads to changes in milk composition. Primiparous mice were fed a 10% or 20% casein-based diet through 2 consecutive reproductive attempts. There was no effect of diet on food consumption or litter size. However, a reduction in dietary protein led to the production of milk with a 12% decrease in protein content and decreased both prenatal and postnatal growth of young. The impact of low levels of dietary protein on milk protein was greater with the increased reproductive demands of concurrent pregnancy and lactation. Significant variation in the protein content of milk was seen among females on the 20% casein-based diet, but not among females on the 10% casein-based diet. Further work is needed to determine the physiological mechanisms that lactating mice might possess to compensate for changes in dietary protein levels, and to determine if the effect of decreased diet quality on the reproductive success of small mammals is similar to the effect of energy availability.

During a study of fawn mortality of sympatric white-tailed (Odocoileus virginianus) and mule deer (O. hemionus eremicus) in west-central Texas from 2004 to 2006, we made observations that should help deer researchers increase their efficiency of capture of fawns, obtain better estimates of ages of fawns, and obtain more reliable estimates of fawn survival. We experimented with vaginal-implant transmitter designs and found that larger holding wings and antennas protruding <1 cm past the vulva resulted in more successful drops at birth sites. White-tailed fawns moved farther from birth sites than mule deer fawns of similar ages (P = 0.027). Our model predicted that white-tailed and mule deer fawns moved an average of 100 m away from birth sites after 12.5 and 17.5 h postpartum, respectively; outliers may be expected. Compared to previously published models estimating ages of captive fawns from new hoof growth, our model predicted that free-ranging fawns were generally 1.5 weeks older. As others have suggested, abandonment induced by marking was rare, and we suggest methods for monitoring does and fawns that could minimize such occurrences. Behavioral and morphological models that we describe may be species-, site-, and time-specific, and biologists should use caution when extrapolating inferences from captive animal–derived models to free-ranging populations.

Alpine ibex (Capra ibex) are polygynous ungulates that exhibit extreme sexual dimorphism and segregation. To test the hypothesis that risk of predation plays a key role in the development of sexual segregation (habitat segregation) in this species, compositions and locations of groups of ibex were recorded from February 2003 to October 2004. Individual fixes of marked adult males and females in the Gran Paradiso National Park in Italy were collected monthly over a 4-year period (January 2000–December 2003). Distances were measured between each location and the nearest refuge area (rocky slopes), and between each location and the nearest source of disturbance (roads and hiking trails). Group size was not related to distances from refuge areas or from sources of disturbance, but sex, age, and weaning played a key role in spatial segregation. During the period of rut, females kept nearer to rocky slopes and further from hiking trails than males. The presence of young also influenced the spatial behavior of females: mothers made use of refuge areas more frequently and of areas near hiking trails less frequently than other females. In contrast, no difference between the spatial behaviors of pregnant and nonpregnant females was recorded in spring. Age played an important role in space use by males, but not by females. Young males (2–5 years) stayed closer to rocks than did middle-aged males (6–11 years), and both stayed closer to rocks than did adult males (>11 years). Adult males stayed closer to hiking trails than middle-aged males; likewise, the latter stayed closer to hiking trails than young males. Males stayed near areas with human presence, likely because of good foraging opportunities. Although our findings do not exclude other explanations, they support the reproductive strategy–predation risk hypothesis. Moreover, predation risk was shown as an important factor leading to both sexual and age segregation in males.

Based on radiotelemetry and snow tracking in 2003 and 2004, we examined habitat selection by red foxes (Vulpes vulpes) in Yellowstone National Park at the 3rd-order (within–home-range selection) and 2nd-order (selection of a home range) scales. We analyzed habitat use using a euclidean distance method that compares distances from each location to each habitat type against expected distances. Overall, red foxes used forested habitats more than open habitats. Red foxes were closer to Douglas-fir (Pseudotsuga menziesii) habitat than expected at both scales, suggesting greater use. Open, mesic grassland at the 2nd-order scale also was used less than expected. Red foxes were farther from ecotones than expected at both scales, a result primarily due to heavy use of Douglas-fir forest, in which they were farther from ecotones than expected, whereas being closer to ecotones than expected in all other habitat types. At the 2nd-order scale, home ranges of red foxes contained more mesic and sagebrush (Artemisia) habitats in winter compared to summer. We hypothesize that competition with coyotes (Canis latrans) greatly impacts habitat use by red foxes. For example, when using coyote-favored habitats with less cover, such as sagebrush and mesic grasslands, red foxes may remain closer to ecotones and thus closer to escape cover. Additionally, their superior mobility in deep snow compared to coyotes may allow red foxes to include more mesic and sagebrush habitats within their home ranges in winter, and thus exploit the greater food resources that have been found to occur in these habitats. Snow tracking and radiotracking revealed similar patterns of habitat use, but snow tracking generated fewer samples because it is labor intensive, only possible after snow events, and not possible outside of winter. However, snow tracking did reveal aspects of red fox behavior that telemetry could not, such as where red foxes foraged. Red foxes in this study may be the native subspecies V. v. macroura, which may partially explain selection for forested habitats and against low-elevation, mesic grasslands.

Mustelids, with their long, thin bodies and poor fat storage capabilities, perform an energetic balancing act when making decisions about energy expenditure. Activity rates provide vital insights into the factors that may affect these energy balances. Using radiotelemetry, we examined factors that affected the likelihood of diurnal activity of fishers (Martes pennanti) in north-central British Columbia, Canada. We assessed the effect of 7 biotic and abiotic factors on the activity of 13 radiotagged fishers by considering 17 models using an information-theoretic approach. The best model suggested that, during the snow-free season, diurnal activity in fishers increased with increasing ambient temperature. The model also predicted that the activity of males increased during the mating season, compared to nonmating periods, whereas activity decreased during the mating season for females without young. Females with young were less likely to be active than females without young. Thus, factors that changed over both short and long terms affected the diurnal activity of fishers. Identifying these factors provides us with a better understanding of how rates of activity, and thus energy expenditure, change through time.

Knowledge of the home range of threatened species is basic to their management and conservation. We describe the home range of the squirrel glider (Petaurus norfolcensis), a threatened marsupial, in the central part of its geographic range in eastern Australia. Thirteen individuals belonging to 6 monogamous social groups were radiotracked for 2–9 months. The adaptive kernel (AK95%) estimate reached an asymptote at approximately 30 locations, giving a mean area of 6.2 ha ± 0.6 SE for the 9 gliders with >30 locations. The AK50% averaged 0.9 ± 0.2 ha, indicating that small core parts of the home range were used intensively. Home ranges of group members (AK95%) showed a high degree of overlap (77%) and when combined averaged 6.7 ± 1.0 ha. They overlapped substantially (50%) with adjacent glider groups but core areas (AK50%) within them overlapped by only 12%. Two of 5 available habitats were well represented in all group home ranges. Habitat dominated by coast banksia (Banksia integrifolia), a key winter nectar food resource, was overrepresented compared to its availability. Conservation measures for this species involving habitat retention or restoration must be informed by recognition of what comprises a preferred local habitat and its distribution.

Dusky-footed woodrats (Neotoma fuscipes) are important components of forest communities, including serving as a primary prey of the California spotted owl (Strix occidentalis occidentalis), a species of concern in California. We examined habitat associations of the dusky-footed woodrat at 4 study sites in mixed-conifer forest of the northern Sierra Nevada, California, during 2003–2005. We investigated the importance of California black oak (Quercus kelloggii) as a macrohabitat component for woodrats, and we examined microhabitat association at 2 levels, house location and house use, by comparing house-site (n = 144) characteristics to random sites (n = 144) and characteristics of used and unused houses, respectively. Woodrat density was positively related to density of large (≥33-cm-diameter at breast height) oaks, probably because large oaks are valuable food resources. Location of woodrat houses was strongly influenced by the presence of large (≥30-cm-mean diameter) logs and large (≥30-cm-diameter at root collar) stumps, but also by steeper slopes, and lack of bare ground and mat-forming shrub cover. We found little evidence that adult woodrats distinguished among houses with respect to microhabitat, suggesting that woodrats make decisions about microhabitat suitability when the house is built. In 2005, adults chose larger houses that were characterized by more logs and less poletimber than those of subadults, but we detected no such differences in 2004. Dusky-footed woodrats in the northern Sierra Nevada would benefit from management techniques that promote the growth and retention of large California black oaks and create large logs and stumps within a stand.

Lower-elevation habitats of north-central Chile are characterized by semiarid vegetation that is strongly influenced by rainfall related to El Niño Southern Oscillation (ENSO) events. During the ENSO warm phase (i.e., El Niño), heavy rains occur resulting in small mammal irruptions or ratadas. During prevailing drier periods, pronounced droughts result in reductions in small mammal densities and local extinctions of some species. Within the dominant thorn-scrub habitat of a national park, we identified 2 other habitat types, aguadas (riverine shrublands) and fog-forest patches that serve as refuges for small mammals during dry years. We divide small mammal species of the thorn scrub into 2 groups: core species (Octodon degus, Phyllotis darwini, Abrothrix olivaceus, and Thylamys elegans) maintain populations at all times, whereas opportunistic species (Oligoryzomys longicaudatus and A. longipilis) are present only after rains. The latter group appears to maintain refuge populations in aguadas and fog forests and to opportunistically exploit the thorn scrub when conditions are favorable. Aguadas also may play an important role in the persistence of less-common species, such as Octodon lunatus and Abrocoma bennetti. Despite being small and patchily distributed, aguadas are important for the maintenance of regional biodiversity.

Intensity of parasitic infection (number of parasites per host) can vary by date, and with host age and sex. We tested whether variation in bladder nematode (Liniscus [= Capillaria] maseri) intensity in Nova Scotian masked shrews (Sorex cinereus) was related to these variables. We collected a total of 117 shrews on 8 different sampling occasions between mid-May and mid-August. Univariate relationships suggested that intensities declined between May and August, and were higher in male shrews. In analyses simultaneously testing for relationships between intensity and date, age, and sex, the most compelling pattern was strongly male-biased parasitism.

The virus family Filoviridae includes 2 genera, the Marburg viruses and the Ebola viruses. The ecology of the filoviruses is poorly known, and indeed their host relationships remain completely unknown. An earlier effort prioritized mammalian taxa as to their possible status as the long-term coevolved reservoir of the filoviruses based on a coarse, regional classification of occurrences; here, we greatly refine the geographic data set for the mammalian taxa based on rich occurrence data sets and range interpolations from ecological niche models for each species involved. This improved detail permits a much more detailed inspection of distributional overlap patterns, and consequently a shorter list of candidate taxa—geographic analysis of 124 mammalian clades led to identification of 55 groups of interest that coincide spatially with known filovirus outbreaks, and fulfill the requirements of several additional assumptions. We discuss implications of our results for the search for the filovirus reservoir, and for research in African mammalogy.

A 1st step in understanding the ecology of rodents as reservoirs and their relation with the disease they transmit is to determine their geographical distribution. This distribution can be modeled as a function of environmental variables. We georeferenced an extensive database of records of the hantavirus reservoir Oligoryzomys longicaudatus (Cricetidae: Sigmodontinae) in Argentina and used generalized linear models to model the probability of the presence of this reservoir as a function of environmental variables. The variables used in the multiple logistic regression were temperature, precipitation, evapotranspiration, altitude, tree cover, grass cover, bare soil cover, and distance to rivers, to water bodies, and to roads; 2 phytogeographic classifications also were included. Spatial autocorrelation was considered in the model by including a spatial dependence covariate. The best model included temperature and precipitation as explanatory variables. External validation showed that the model without the space covariate correctly classified 95% of the sites with the rodent and 70% of the sites without it; the model including the spatial term correctly classified 100% of the sites with the rodent and 70% of the sites without it. A secondary model included days with frost and percent cover by bare soil as explanatory variables. O. longicaudatus was recorded in 97% of sites in the High Andean–Subantarctic regions, 65% of sites in the Monte–Espinal–Patagonian regions, and 0% of sites in the Pampean region.