We studied nectar-feeding behavior of 3 pteropodid bats under natural conditions. Cynopterus sphinx and Pteropus giganteus visited Ceiba pentandra trees throughout the night, whereas Rousettus leschenaulti visited only during early evening. Peak visits occurred at 2300 h for C. sphinx and 2000–2100 h for P. giganteus, coinciding with maximum nectar production and sugar concentration of floral resources. C. sphinx foraged at 6–10 m, R. leschenaulti at 10–18 m and P. giganteus at 15–20 m heights in the trees. Chemiluminescent-tagged C. sphinx foraged on nectar mostly in single trees until midnight and switched to 2–4 nearby trees later. We observed coats of pollen of C. pentandra on the abdomens, wings, and heads in 40% of C. sphinx captured in mist nets. Pollen loads on the abdomen were greater on males than on females. Our observations on R. leschenaulti and P. giganteus also showed adherence of pollen grains on their bodies. Presence of pollen grains on the bodies of these bats strongly suggests that they pollinate C. pentandra.

Old World fruit bats (family Pteropodidae) are common throughout the Paleotropics, where they play an important ecological role as seed dispersers and pollinators. Although many regions host diverse assemblages of fruit bats, mechanisms of resource partitioning are only beginning to be documented. This study investigates the potential role of feeding behavior in patterns of resource use within a sympatric assemblage of pteropodids from Papua New Guinea. Individuals of Syconycteris australis, Dobsonia minor, Pteropus conspicillatus, Nyctimene albiventer, and Paranyctimene raptor were videotaped during feeding experiments designed to elicit shifts in feeding (biting) behavior by varying fruit hardness. Although significant variation exists among species in biting behavior, the clear association between trophic ecology and feeding behavior seen in New World fruit bats does not exist in this assemblage of Old World species. Rather, the combinations of behavior and morphology exhibited by these bats appear to represent 2 different solutions to the ecological challenge of feeding on relatively hard fruits.

Chitinase was found in the intestines of 9 species of 6 genera of bats of Indiana. Included were the northern myotis, Myotis septentrionalis; the little brown myotis, M. lucifugus; the Indiana myotis, Myotis sodalis, the big brown bat, Eptesicus fuscus, the eastern pipistrelle, Pipistrellus subflavus, the evening bat, Nycticeius humeralis, the red bat, Lasiurus borealis, the hoary bat, L. cinereus, and the silver-haired bat, Lasionycteris noctivagans. Chitinase was found in summer and in winter, but at significantly lower levels in winter. Chitinase in summer may help to separate parts of insects by breaking down softer connective tissue. In winter, it may break down remnants of chitin left over from summer foraging and could even serve as a supplemental source of energy and nutrients. Chitinase was produced in these bats by 6 previously known species of chitinase-producing bacteria, 2 of Serratia, 3 of Bacillus, and 1 of Enterobacter, and by 4 species previously unknown to produce chitinase, Hafnia alvei, Citrobacter amelonaticus, Enterobacter aerogenes, and E. cloacae.

Two hundred and eight wild-caught cheetahs (Acinonyx jubatus jubatus) were live trapped on Namibian farmlands and examined for signs of dental anomalies. Three anomalies were recorded: erosion of the upper palate (possibly a predisposition to focal palatine erosion, where the first lower molar penetrates the palatine mucosa), crowding of lower incisors, and absence of one or both upper premolars. Just over 40% of cheetahs examined showed deep palatine erosion, and 15.3% of these had perforated upper palates. In addition, 31.7% of cheetahs examined had crowded lower incisors and 20.9% had one or both upper premolars missing. The incidence of focal palatine erosion is of particular interest as it has previously been recorded only in captive cheetahs, where it was attributed to a soft captive diet, and not previously recorded for wild individuals. To attempt further understanding of potential causes of such erosion, degree of erosion was examined in relation to sex, age, region, time in captivity, and occurrence of other dental anomalies. No relationship was found between severity of erosion and time spent in captivity, while juveniles showed more severe erosion than adult cheetahs. Cheetahs missing either one or both upper premolars showed a higher incidence of deep erosion, as was true for cheetahs that exhibited crowded lower incisors. The traditional explanation of focal palatine erosion being an artifact of captivity does not explain its occurrence in this sample population of cheetahs, the majority of which were raised entirely in the wild.

Of 14 species of marmots (genus Marmota, Family Sciuridae), only 2, the woodchuck (M. monax) and yellow-bellied marmot (M. flaviventris), have not been reported to be obligate social hibernators. There is one published report of yellow-bellied marmot juveniles hibernating together at a subalpine site, and social hibernation was reported at a single high-alpine site. Solitary hibernation is expected in woodchucks because they do not share burrows during summer, but is unexpected in yellow-bellied marmots, a harem-polygynous species where females may share burrows and have extensive home-range overlap with female kin during summer. We documented emergence patterns in 13 matrilines to determine whether adult marmots hibernate socially. We found that adult males hibernated with 1 or more adult females, and mothers hibernated with their offspring. Therefore, we conclude that yellow-bellied marmots hibernate socially. There is, however, no evidence that suggests that yellow-bellied marmots receive social thermoregulatory benefits from social hibernation. Documenting social hibernation required us to quantify patterns of emergence from hibernation. Throughout our subalpine site, emergence appears to be getting earlier; a result consistent with a previous report based on 1 colony site and which suggests the effects of global climate change are affecting hibernation patterns.

We radiotracked 23 Japanese dormice (Glirulus japonicus) in a natural oak forest and a larch plantation to locate their daily rest sites. In 363 tracking days, 123 rest sites were used, 72% in trees and 28% in shallow underground sites or a rock crevice. Nest boxes and tree cavities were the most frequently used rest sites in trees. Natural arboreal rest sites and nest boxes were used regularly by individual dormice, whereas most underground rest sites were used for only 1 day. Nest boxes and underground rest sites were used more frequently in the larch plantation than in the oak forest. Males used nest boxes more than underground rest sites, whereas females regularly used the same natural arboreal rest sites. Dormice had large home ranges relative to their body mass. Males had larger home ranges and moved for longer distances at night than did females. A close relationship between rest-site use and daily torpor was apparent; nesting material was not found in natural rest sites used only once, and dormice frequently changed their rest sites.

We have studied the effect of habitat and presence of conspecifics on echolocation characteristics of the emballonurid bat Balantiopteryx plicata. Calls during the search phase only showed differences between habitats in bandwidth, as has been found for other open-space bats. Characteristics of calls during the approach phase did change when bats entered open areas. Calls in the terminal phase showed no differences in the characters examined between habitats. Bats flying in groups shifted their peak frequency significantly, which maximized differences between individuals. These results are interpreted as an active mechanism of jamming avoidance. Bats flying in groups also tended to increase the mean of peak frequencies.

Many animals have geographic variation or dialect differences in their vocalizations. These differences combined with social behavior and isolation can contribute to speciation. We compared the acoustic vocalizations of 3 subspecies of Spermophilus lateralis and those of S. saturatus using wild-caught animals in the presence of a predator, Canis lupus familiarus. Variation was examined using 9 sonogram variables. We found both local dialect differences and geographic variation in alarm calls. S. saturatus could be distinguished 100% of the time from S. lateralis using discriminant analysis. Widespread use of ultrasonic vocalizations was found in both S. lateralis and S. saturatus. Dialect differences showed a pattern of character displacement between adjacent subspecies. Vocalization parameters changed within local sites and between years, suggesting alarm calling is at least partially a learned behavior. Species share more uniquely defining vocalization variables than either subspecies or local populations.

Understanding patterns of burrow-use behavior can provide insights into social structure and may have important implications for management of threatened or endangered species. Most kangaroo rat species are assumed to be solitary, but some populations of the endangered Stephens' kangaroo rat (Dipodomys stephensi) exhibit aggregated burrow associations. Observation of burrow-use patterns over a period of 2 years allowed us to assess the extent of burrow sharing, providing insights into the degree of sociality in this species. Understanding burrow-use patterns also is critical for conservation because the most widely used technique for population estimation for this species relies on a linear relation between burrow density and population size. Although the density of burrow entrances is known to correlate positively with population density, very little is known about how robust this correlation is in the face of changing demographic and environmental variables. Over 14 three-night sessions, burrow entrance sharing occurred between 26% of individuals, with up to 4 individuals sharing a single burrow entrance. The predominant burrow sharing combination (42%) was adult males with adult females. The number of burrow entrances used varied by location and by age of inhabitant. The relationship between density of burrow entrances and that of D. stephensi varied significantly by location but not by date, and individuals in high-density populations used fewer burrow entrances than individuals in low-density populations. Consequently, variation in location, population density, and ratio of juveniles to adults should all be considered when using the method of counting burrow entrances to estimate population size. When these factors vary, the relationship of burrow entrance count to D. stephensi density may need to be recalibrated to predict density accurately. We recommend this method be employed cautiously and that results obtained be interpreted as conservative estimates of population size.

Effective population sizes reported in the literature typically range from a small fraction of the adult population to about half the number of breeding adults. Theoretically, however, social structuring of genetic diversity could produce effective sizes as great as or even greater than population size. A colony of the highly social black-tailed prairie dog (Cynomys ludovicianus) was studied in the field for 16 years, and data were gathered for estimation of effective population sizes from pedigrees, demography, and allozyme alleles. Social breeding groups (“coteries”) within the colony exhibited high correlations of genes among individuals, and different coteries exhibited substantial genetic differentiation. Genetic diversity thus occurred within individuals, within coteries, and among coteries, and shifted among these levels of organization over time. “Instantaneous” estimates of effective size from short-term (annual) changes in genetic correlations were calculated from pedigree information but were not useful because they produced a wide diversity of estimates, due in part to the lack of demographic and genetic equilibrium in the colony. “Asymptotic” measures of effective population size that assumed eventual genetic equilibrium yielded relatively consistent estimates of effective sizes. For 10 years of empirical results from prairie dogs, effective population sizes from pedigrees (harmonic mean = 79.4), demographic model based on breeding groups (asymptote = 88.5), and allozyme data (harmonic mean = 88.9) were similar, and all were somewhat higher than the number of adults in the population (harmonic mean = 74.1). The colony of prairie dogs, therefore, exhibited a lower rate of loss of genetic diversity than expected, due to the genetic substructure created by the presence of social breeding groups.

Hoarding strategies range between scatterhoarding (small multiple hoards) and larderhoarding (large single hoard). We hypothesized that spatial distribution of food affects hoarding strategy of 2 nocturnal psammophilic rodents, Gerbillus pyramidum and G. allenbyi. We used a modular arena to test the prediction that hoarding strategy would tend toward scatterhoarding as travel distance during foraging increases. We manipulated travel distance and studied its effect on hoarding behavior. G. allenbyi, as predicted, tended to scatterhoard as travel distance increased. G. pyramidum, however, reacted to changes in travel distance by moving the location of its larderhoard but did not scatterhoard. We suggest that hoarding strategy may be scale dependent and that gerbils will increase their number of hoards when energy costs of travel are sufficiently high.

We investigated site fidelity of territorial male guanacos (Lama guanicoe) in Torres del Paine National Park, Chile. The study took place over a 10-year period, with intensive work in the final years, 1997–1999. Guanacos have a social system of resource-defense polygyny with fluid movement of females between male territories. After the annual winter migration, males establish and maintain their territories from mid-spring until late autumn. Territorial males are classified as solo or family-group territorial males. We collected data on type, location, size, and usage of territories for tagged, known-age males. We compared male territorial fidelity between mating (8 December–11 January) and nonmating periods within the 6-month territorial season each year (1 October–15 March) and between multiple years. Males used the same area within the 1997 and 1998 territorial seasons (n = 47). Most males (73%; n = 60) also returned to the same territory location from year to year. Males (27%) that shifted territorial locations showed no clear patterns in changes between solo territorial males and family-group territorial males. High predictability of male territory sites within a given year and between years has short- and long-term benefits for management and conservation efforts.

Quantitative assessments of home-range dynamics and movements of long-tailed weasels (Mustela frenata) are lacking, in spite of the importance of these data to understanding how habitat fragmentation influences behavior, ecology, and interspecific interactions. During autumn to late winter 1998–2000, we monitored 11 long-tailed weasels (7 male, 4 female) via radiotelemetry to examine home-range dynamics and movement rates in an Indiana landscape fragmented by agriculture. Mean (± SE) 95% adaptive kernel contour area for adult females and adult males was 51.8 ± 8.1 ha and 180.3 ± 60.3 ha, respectively, and differed significantly. Hourly rate of movement for male long-tailed weasels (130.5 ± 12.7 m) was greater than that of females (79.2 ± 13.5 m). Weasels demonstrated greater hourly rates of movement during the fallow season (138.2 ± 12.8 m) compared with the preharvest season (63.0 ± 11.2 m). Mean hourly rates of movement were lower in corridors, forest patches, and grassland patches compared to crop fields. Mean hourly rate of movement was positively related with home-range size (P < 0.001) with the greatest rates of movement in the largest home ranges. Mean hourly rate of movement varied inversely with prey biomass (P = 0.07). Our results are consistent with the notion that long-tailed weasels may be sensitive to agriculturally induced fragmentation of habitat and the importance of maintaining landscape connectivity for species conservation.

Conservation of small mammals requires knowledge of ecologically meaningful spatial scales (e.g., individuals or populations) at which species respond to habitat heterogeneity. Between July and October of 1998, we sampled small mammals, understory vegetation, and downed wood (DW) at multiple scales (trap sites, 1-hectare forest patches, and stands) in 2 Douglas-fir (Pseudotsuga menziesii) forests in western Oregon. Our objectives were to determine if DW or understory vegetation varied among or within forest patches or among forest stands and whether variation in survival of small mammals coincided with the scale in which these varied. Understory vegetation explained most of the variation within patches, but did not vary among patches or stands. Survival of the 2 most abundant species, the deer mouse (Peromyscus maniculatus) and creeping vole (Microtus oregoni), also varied within patches by differing among individual home ranges, and was most related to DW volume (cubic meters per 0.01 hectare) and herb and gass cover (%). Survival of deer mice was explained by a 2nd-degree polynomial function of DW within individual home ranges, and peaked at 2.0 m³ per 0.01 ha. Survival of creeping voles was dependent on a negative log_e function of DW within home ranges, and was highest in home ranges lacking DW. Our results demonstrate that these species may not be generalists, as previously suspected, but rather specialists tied to specific amounts of particular habitat components within home ranges. We recommend that future studies of relationships between small mammals and habitats consider multiple spatial scales that are ecologically meaningful for the species of interest (e.g., home ranges), and examine demographic parameters including survival.

We investigated short-term effects of ski-run development on the dynamics of small mammal populations at Vail Ski Area, Colorado. We compared a new ski run, an experimental ski run with added woody debris, a forest adjacent to a new ski run, and a control forest outside ski development by estimating density and survival of common small mammals using Pollock's robust design. In 4 summers (1998–2001), 16,800 trap nights resulted in 1,276 captures of 668 individuals. Before ski-run development, Clethrionomys gapperi was most abundant in forested areas, but after, density was greatest in the forested site adjacent to a new ski run and next highest on the experimental ski run. C. gapperi survival was similar across sites and years. Peromyscus maniculatus and Tamias minimus densities were greatest on the ski run without woody debris and lowest on the forested control site. Estimated survival of T. minimus varied more by year than by site. Greatest densities of Phenacomys intermedius occurred on the 2 ski runs in years following development, and densities were low on forested sites. Peromyscus maniculatus and Phenacomys intermedius captures were insufficient to estimate survival. Our results suggest that C. gapperi, in the short term, will inhabit ski runs with tree islands and woody debris. Additional studies on impacts of ski-run development are needed to understand small mammal responses and to promote effective management strategies for maintaining populations of forest-dwelling animals.

We studied dispersal and breeding patterns in a solitary gerbil, Meriones tamariscinus, from 1995 to 1999 in Kalmykia, southern Russia. The females of this species delay breeding far beyond the age of maturation. We suggest that delayed breeding in young females is associated with delayed emigration from the natal site. Most young female M. tamariscinus showed strong natal philopatry that resulted in female kin clustering. Proximity to adult females suppressed their maturation and restricted breeding opportunities. Breeding rate of young females correlated negatively with the survival rate of adult females. Therefore, dispersal and breeding patterns in this solitary species appear similar to those in social (group living) species of gerbils. Results are discussed in terms of ecological, demographic, and life-history traits of this species that set constraints on dispersal and breeding in young females.

We observed mating by Brazilian free-tailed bats (Tadarida brasiliensis) in central Texas between 21 March and 5 April 1998. We documented copulations in large and small day roosts and in temporary night roosts. Focal animal sampling at a highway bridge revealed an aggressive and a passive male copulation strategy that may function as adaptations to different roost conditions. During aggressive copulation, the male separates a female from a roost cluster and restricts her movements during mating while he emits characteristic calls. During passive copulation, the male moves very slowly onto a female that roosts in a dense cluster. Passive copulations occur without resistance from the female and without male vocalizations. Both males and females mate with multiple partners, suggesting that mating is promiscuous. The mating system in a large highway bridge colony is characterized as mating aggregations or swarming because mating occurs in large, temporally unstable multimale and multifemale mating groups, with no apparent male territories or defense of females.

Moles are the only fertile true hermaphrodites described up to now among mammals. This paper investigates the development and growth of the mole Talpa occidentalis. Fifteen developmental stages (8 prenatal and 7 postnatal) were established and 12 of them, ranging from early gestation to weaning, are described in detail. The growth of moles was shown to fit triphasic curves for both males and females. The coefficient of reproductive effort of females, defined as mass of the litter at weaning relative to maternal body mass, is inversely proportional to mass of the female, according to an exponential function. Compared with other insectivores with lower body mass (shrews), this coefficient in female moles (2.69) is significantly higher than expected (1.91), which implies that reproductive effort of moles is 36% greater. This study provides the chronological criteria (based on body mass, crown–rump length, and major external morphological features) needed for age determination of individual developing moles and thus represents a useful tool for further studies in these mammals.

The phyllostomid bat genus Vampyressa often has been allied with Uroderma, Chiroderma, Platyrrhinus, Vampyrodes, and Mesophylla. However, the relationships among the genera have proven difficult to resolve, and a number of studies have suggested that Vampyressa is not monophyletic. Mesophylla includes a single species, which some taxonomists have placed in Vampyressa and others in the more distantly related genus Ectophylla. Our analysis of sequence data from the cytochrome-b gene (Cytb) gives strong support for Mesophylla being closely related to Vampyressa, rather than Ectophylla. Examination of the Cytb data indicates that Vampyressa pusilla and Mesophylla are members of a lineage distinct from V. bidens and V. brocki. Therefore, we recognize the genus Vampyriscus for V. brocki and V. bidens. Brazilian specimens of V. pusilla are strongly divergent from specimens from elsewhere in Latin America. The degree of genetic distance indicates species-level divergence between these taxa, and supports the recent recognition of Vampyressa thyone for the northern populations.

Phylogenetic reconstructions based on molecular data have shown recurrent morphological convergence during evolution of the species-rich genus Myotis. Species or groups of species with similar feeding strategies have evolved independently several times to produce remarkable similarities in external morphology. In this context, we investigated the contentious phylogenetic position of 1 of the 2 piscivorous bat species, Myotis vivesi, which was not included in previous molecular studies. This bat, endemic to the coasts and islands of the Gulf of California, Mexico, was long classified in its own genus, Pizonyx, because of its distinctive morphology. To reconstruct its phylogenetic origins relative to other Myotis, we sequenced the mitochondrial cytochrome-b gene of 2 M. vivesi and related vespertilionids. These outgroups included Pipistrellus subflavus, a member of the subgenus Perimyotis, sometimes classified within the genus Myotis. Unexpectedly, all reconstructions placed M. vivesi within a strongly supported clade including all other typical neotropical and Nearctic Myotis. This molecular phylogeny supports an endemic radiation of New World Myotis. Other Myotis species with similar adaptations to gaffing prey from the water surface present no close phylogenetic relationships with M. vivesi, indicating that such adaptations are convergences. On the other hand, P. subflavus is genetically as distant from the genus Myotis as from other Pipistrellus species, suggesting that generic rank to Perimyotis is warranted.

Natural recolonization by large carnivores has rarely been documented. American black bears (Ursus americanus) recently (1988-present) recolonized portions of their former range in western Texas. We used mtDNA sequence data (n = 144 bears) from 7 populations of southwestern black bears in New Mexico, Texas, and northern Mexico to test predictions regarding metapopulation structure of the species in this region and the source of recolonization in western Texas. Six variable nucleotides were detected, resulting in 5 mtDNA haplotypes. Although within-site diversity of haplotypes (h) and nucleotides (π) was low, a high degree of genetic partitioning among sites was detected (ϕ_ST = 0.6301). Analyses pinpointed northern Mexico as the source of black bears for western Texas. Female-mediated gene flow is proceeding slowly in this system (N_fm = 0.4961 individuals/generation), but its occurrence was inferred via field observations. Nested clade analyses indicated that populations of bears in the Mexico–Texas region (area that encompasses mountain ranges within Nuevo Leon and Coahuila, Mexico, northward to smaller ranges located in the Trans-Pecos region of western Texas) were connected via restricted gene flow due to isolation by distance. Long-distance colonization is the likely cause of extant geographical associations between New Mexican and Mexico–Texas populations. The naturally fragmented, xeric environment of the Chihuahuan Desert impedes colonization, but is not a complete barrier to this process. Conservation initiatives concerning recolonization by black bears within the Mexico–Texas mainland–island metapopulation should focus on preventing human–bear interactions and maintaining corridors for dispersal between the mainland populations in Mexico and the island populations in western Texas.

Species limits in the genus Oxymycterus have been controversial because of difficulties in detecting discrete morphological and cytogenetic variation. Several authors have considered many of the species described from Brazil to be conspecific with O. rufus, including O. dasytrichus described from Bahia. This tendency represents a null hypothesis for the species-level diversity within the genus. A recently proposed alternative hypothesis based on analyses of allopatric samples recognizes O. rufus and O. dasytrichus as valid species within rufus and dasytrichus species complexes, respectively. Two sympatric forms of Oxymycterus from Viçosa, Minas Gerais State, southeastern Brazil, are phenotypically similar to members of these 2 species-groups. Investigation on the status of these populations and their relationships to the rufus and dasytrichus complexes provided a test of the alternative hypothesis regarding diversity within the genus. Morphometric, morphological, and molecular (cytochrome-b DNA sequences) comparisons of samples representing the rufus, dasytrichus, and judex species-groups provided evidence that the 2 sympatric forms from Viçosa are distinct evolutionary units, one related to the dasytrichus species-group and the other to the rufus species-group. The structures of morphological and molecular variation within each species-group supported an isolation-by-distance model of phenotypic differentiation in the rufus group, and a smooth pattern of phenotypic differentiation along a north–south axis in the dasytrichus group. The relevance of these patterns for species delimitation within these groups and the validity of O. dasytrichus and O. rufus are discussed.

The genus Baiomys contains 2 extant species, the northern B. taylori and the southern B. musculus. Mitochondrial DNA sequences from the cytochrome-b gene were used to assess genetic variation within and between the 2 species. Samples of B. taylori and B. musculus each formed 2 separate clades and differed by an average sequence divergence of 11.62%. Average sequence divergence between the 2 clades of B. taylori was minimal (2.82%), whereas the value between the 2 clades of B. musculus was greater (6.46%). The level of genetic divergence between the clades of B. musculus is comparable to values seen between other sister species of sigmodontine rodents. The Trans-Mexican Volcanic Belt, Sierre Madre del Sur, and Rio Balsas may separate populations of B. musculus into northwestern and southern clades.