For nearly a century the fields of mammalogy and paleomammalogy have complemented each other, although the relative influence of one on the other has waxed and waned. The development of new techniques, databases, and information-handling capabilities in the past decades have enhanced the potential for working at the interface between these 2 fields in ways never before possible. This portends an elevated role for mammalogy in the development of ecological and evolutionary theory and serves as a model for merging paleontological and neontological data in other disciplines.

Paleontological information was used to evaluate and compare how Rocky Mountain mammalian communities changed during past global warming events characterized by different durations (350, ∼10,000–20,000, and 4 million years) and different per–100-year warming rates (1.0°C, 0.1°C, 0.06–0.08°C, 0.0002–0.0003°C per 100 years). Our goals were to determine whether biotic changes observed today are characteristic of or accelerated relative to what took place during past global warming events and to clarify the possible trajectory of mammalian faunal change that climate change may initiate. This determination is complicated because actual warming rates scale inversely with the time during which temperature is measured, and species with different life-history strategies respond (or do not) in different ways. Nevertheless, examination of past global warming episodes suggested that approximately concurrent with warming, a predictable sequence of biotic events occurs at the regional scale of the central and northern United States Rocky Mountains. First, phenotypic and density changes in populations are detectable within 100 years. Extinction of some species, noticeable changes in taxonomic composition of communities, and possibly reduction in species richness follow as warming extends to a few thousand years. Faunal turnover nears 100% and species diversity may increase when warm temperatures last hundreds of thousands to millions of years, because speciation takes place and faunal changes initiated by a variety of shorter-term processes accumulate. Climate-induced faunal changes reported for the current global warming episode probably do not yet exceed the normal background rate, but continued warming during the next few decades, especially combined with the many other pressures of humans on natural ecosystems, has a high probability of producing effects that have not been experienced often, if ever, in mammalian history.

Quantitative analysis of molar shape may provide a metric for paleontological phylogeography or the study of intraspecific relationships in the fossil record. In this study, outlines of the lower 3rd molars (m3) of North American Marmota were analyzed as between-shape distances after ordination with eigenshape analysis. Based on comparisons with cytochrome b, quantitative divergence in molar shape appears to be a reasonable proxy for phylogenetic reconstruction at the level of populations, subspecies, and the most closely related species of marmots. Phylogeographic analysis of living North American marmots and middle Pleistocene fossils from Porcupine Cave, Colorado, revealed that the latter were more closely related to extant Marmota monax than they are to M. flaviventris, which currently inhabits the Porcupine Cave area, suggesting that the origin of living species occurred in regions different from those they inhabit today. Change in molar shape was significant from level to level through the Porcupine Cave section, which spans a glacial–interglacial cycle, but was not correlated with environmental change. The amount of morphological difference among conspecific populations of living M. monax suggested that they differentiated over many glacial cycles, whereas morphological differences between M. caligata and M. flaviventris were smaller and may have evolved over fewer cycles.

Much attention has been focused on the response of species to the climate change associated with the last deglaciation during the Pleistocene. Generally, species respond in an individualistic manner to climate change, and expand and contract their ranges independently; consequently, community composition is extremely variable over time. Although data are available to examine range shifts of species by mapping species ranges over time, most investigations to date have been qualitative. I quantitatively assessed changes in distributions of species to determine the degree to which species shifted their ranges independently over broad time scales. Data on Pleistocene mammal assemblages from the FAUNMAP database were divided into 4 time periods (Pre-Glacial, full Glacial, Post-Glacial, and Modern). Range shifts were characterized by change in the median position of the range from 1 time period to another, change in range size, and direction of the shift. The degree to which species were shifting their ranges independently of one another was evaluated by examining frequency distributions of each range shift parameter and comparing directions wherein species were shifting their range centroids. Many species are shifting their ranges in similar ways. Many species in each time transition change their range size very little. Species shift their range centroids, on average, between 1,200 and 1,400 km. Moreover, if the United States is divided into quadrats and the direction in which species with those quadrats shift their ranges is examined, it becomes clear that in each quadrat there are some directions that are favored over others. The majority of these distributions in the 2 oldest transitions differ from a uniform distribution. Therefore, the prediction that the individualistic responses of species to climate change should result in nonanalog communities likely is oversimplified.

We traced a population of Ctenomys sociabilis, a highly endemic South American tuco-tuco, through 1,000 years to assess its response to climatic change and recent human disturbance. Samples were obtained from a late-Holocene raptor roost in Parque Nacional Nahuel Huapi, Argentina, which produced a diverse and abundant rodent fauna, with >10 genera extending from the present to 950 ± 50 years ago (CAMS-45936). The site (Estancia Nahuel Huapi locality 1) was located near the center of the present geographic range of C. sociabilis, which occurs throughout 8 of 9 stratigraphic levels in the site. To examine genetic structure through time, we extracted ancient DNA from 16 teeth at those levels and from 1 modern tooth at the surface for a total of 17 specimens. Cytochrome-b sequences from ancient and modern specimens were compared with a modern tuco-tuco sequence from the extant local population. Our results show that of those 17 specimens, all but 1 had identical sequences. Further, these sequences were identical to a representative of the modern population. Thus, that population has remained genetically identical for at least 1,000 years in the face of climatic change, human disturbance, and proximity of other tuco-tuco species (C. haigi, C. maulinus) with adjacent geographic distributions. Our findings indicate that a population bottleneck contributing to low genetic diversity of C. sociabilis occurred before 1,000 years ago and that late-Holocene climatic change occurred without a corresponding impact on the genetic diversity of this species.

Mortality profiles can be used to investigate modes of accumulation of fossil assemblages, including predation by ancient nonhuman and human (Homo) hunters. Prey age at death reflects hunting decisions and opportunities in terms of calories returned for energy spent and risks taken. Nonhuman carnivores commonly harvest vulnerable individuals (young and old), whereas humans consistently can take prime adults. As an example of how mortality profiles can be used to illuminate predator behavior, this article examines when the ability to select prime-age animals emerged during human behavioral evolution. Although it would be expected that the appearance of this behavior coincided with the appearance of morphologically and archaeologically modern humans, analyses of archaeological assemblages from western Europe and South Africa suggest that this trait was already present in archaic people who preceded modern humans. Studying age distributions in fossil assemblages is not without its limitations, including the difficulty of estimating age at death in fossil specimens, pre- and postdepositional biases, and reconstructing the age structure and behavior of prey herds. Nevertheless, valuable behavioral information can be gained by using controlled comparisons of many assemblages.

Body mass distributions of mammalian species are a major focus of macroecological and macroevolutionary studies. However, these distributions may be obscured by taxonomic error, just like any other aspect of biodiversity. The key problem with taxonomy is that many currently used names are synonyms of each other or are biologically indeterminate. This article reassesses body mass patterns in the fossil record of North American mammals using the recently developed flux ratio method for estimating the underlying proportion of invalid names. Current name quality varies very strongly with body mass: small species names are highly unreliable, but names of large species have been evaluated thoroughly. The main reason is that there has been a dramatic fall through historical time in the average size of described species. Hence, there simply has not been enough time yet to reevaluate the names of most small species. This bias only accentuates the previously described bimodal diversity distribution for North American mammals, which suggests the existence of dual body mass optima—so not all evolutionary lineages converge on 100 g. The historical shift in the underlying quality and body mass of newly described species also differentially affects our picture of biodiversity in major taxonomic groups. On the one hand, ungulate and carnivoran names are much more likely to be invalid in the 1st place than are rodent and insectivoran names. On the other hand, most of the invalid names for large mammals already have been identified, but this is not true for the small-mammal groups. Therefore, the most fruitful strategy for future taxonomic research would be to focus on small- and medium-sized mammals.

Temporal information on mammalian evolution allows testing of hypotheses about the mode of speciation and extinction, comparison of rates of evolution across taxa, and correlation of cladogenesis with important geological processes. Important insights can be made from combining data from fossils and molecules (DNA sequences), and relevant methods are expanding. When considering these methods, careful consideration should be given to features affecting time estimation (e.g., accuracy of tree construction, branch length estimation, taxonomic and genomic sampling, and sources of genetic and calibration errors). We report on the available methods that aid in evolutionary time estimation from molecular data and corresponding fossils. We recommend several steps to improve this process. First, we recommend using appropriate DNA substitution models to help correct DNA distance estimates and construct trees with more reliable branch lengths. Second, we recommend using multiple fossil calibration dates where possible. Third, in general, we recommend a conservative approach to time estimation by reporting inherent errors associated with genetic distances, calibration selection and application. In conclusion, temporal data derived from molecular clocks should be regarded in light of their dependence on paleontological information and their synergy with fossil data rather than competing with paleontological information. Thus, despite the varied sources of error, we encourage the extraction of time from molecular data with careful examination of potential biases.

We provide stable carbon isotope data from 37 species of African bovids to document dietary preferences for C₃ browse (or fruits) or C₄ grass. These data provide a quantitative measure of the fraction of C₄ grass in bovid diets, can be applied on regional to local scales, can be derived from tooth enamel and hair or other tissues, and permit the diets of bovids to be considered in the context of a grazer–browser continuum. We recognize hypergrazers (>95% C₄ grass), grazers (70–95% C₄ grass), mixed feeders (>30% C₄ grass and >30% C₃ browse), browsers (70–95% C₃ browse), and hyperbrowsers or frugivores (>95% C₃ browse or fruit). Our results suggest that, of the extant East African Bovidae, impala (Aepyceros melampus), Thomson’s gazelle (Gazella thomsonii), and oribi (Ourebia ourebi) can be construed as mixed feeders. Dietary estimates based on stable isotope analysis are in broad agreement with other measures of diet such as hypsodonty index, mass relationships, and wear scratches on enamel.

Although bovids have been studied for decades, debate still exists about their diets. To address this problem, we examined bovid dietary ecology through analysis of stable carbon isotopes. We analyzed tooth enamel, bone collagen, and hair from 312 individual bovids, representing 27 species from southern Africa. Although dietary information from the literature is usually supported by this technique, our results and the literature are sometimes highly divergent. For instance, our results indicate that Taurotragus oryx and Raphicerus campestris eat less grass than is widely believed. Furthermore, contrary to most theoretical expectations, our data indicate no relationship between body size and percentage of monocots consumed by southern African Bovidae. Although many researchers have abandoned the idea that bovid soft-tissue anatomy is strongly indicative of diet, we demonstrate a strong relationship between the percentage of grass in a bovid’s diet and several hard-tissue craniodental indices.

The woolly flying squirrel (Eupetaurus cinereus) is an extremely aberrant sciurid. It is the longest squirrel in the world and the only sciurid with hypsodont dentition. Most of the information on this species comes from a few study skins collected from the western Himalayas over a century ago. The unusual tooth structure of the squirrel led to suppositions about its diet, including the supposition that it ate moss and lichens scraped from rocks. In 1994, 1995, and 1996, we analyzed fecal samples from 4 squirrels. All 4 squirrels ate 92–100% pine needles. These data, coupled with observations of captive and recently released specimens, indicated that woolly flying squirrels feed, mostly or entirely, on pine needles. Such a diet is extremely unusual for a mammal and may explain the squirrel’s unusual tooth structure. Destruction of high-elevation pine woodlands in this region is a distinct and immediate threat to the survival of this species.

Olfaction plays an important role in the foraging behavior of rodents, but little is known about how this sense varies among taxa that evolved in different ecological settings. Field experiments were conducted in 10- by 10-m enclosures to test for interspecific differences in foraging success for ponderosa pine (Pinus ponderosa) or sunflower seeds, based on olfaction, of 4 rodent species: 2 heteromyid rodents (Panamint kangaroo rat, Dipodomys panamintinus, and Great Basin pocket mouse, Perognathus parvus) and 2 nonheteromyid rodents (yellow pine chipmunk, Tamias amoenus, and deer mouse, Peromyscus maniculatus). All species found large, shallow caches more frequently than small, deep caches. Chipmunks had the lowest foraging success for buried sunflower seeds under dry conditions. Deer mice did as well as the heteromyid rodents on large shallow caches but found relatively few small, deep caches. The heteromyids were the only species that found small, deep sunflower seed caches under dry conditions, and Panamint kangaroo rats always found more caches than did Great Basin pocket mice. These results confirm that olfaction plays an important role in foraging of rodents for buried seeds and support the notion that the olfactory sense of rodent species has evolved greater sensitivity to seeds in different ecological contexts.

Black-footed ferrets (Mustela nigripes) and Siberian polecats (M. eversmannii) are medium-sized (about 1 kg) mustelids with similar ecological and morphological characteristics. We measured basal metabolic rates (BMR) for both species. In contrast with the commonly stated belief that mustelids have relatively high mass-specific BMR, neither the BMR of ferrets nor that of polecats in winter was greater than standard allometric predictions for all mammals. As suggested by previous authors, we believe that our relatively lower measurements for BMR are due to our efforts to minimize stress during the experimental procedure. These results support the contention that BMR in mustelids is no different from what is expected of mammals of this body mass. Seasonal differences were found in polecat BMR (higher in summer) but not in ferret BMR. Reasons for this interspecific difference may relate to differences in natural histories of these species.

I studied reproduction and postnatal ontogeny in a captive population of the African water rat, Dasymys incomtus, whose numbers have declined since the 1960s. Mean litter size was 2.9, gestation was 29 days, and maximum reproductive output was 18 young. Neonates were altricial and weighed 6.1–10.3 g. Weaning occurred at 24 days, and sexual maturity was attained at 6 weeks in males and 17 weeks in females. The estrous cycle was 7–16 days, the variation being caused by prolonged estrus. Comparisons with other African murid rodents suggest that the low reproductive output and prolonged postnatal ontogeny of D. incomtus reflect phylogenetic constraints imposed by an altricial strategy and nipple clinging but also may be adaptive responses to the stable and predictable mesic habitats occupied by D. incomtus. However, the low reproductive rate compromises its ability to cope with continued habitat destruction and desiccation, and populations of D. incomtus can be expected to decline further.

Little is known about the behavior of male and female rodents at parturition. We documented behavior during and immediately after parturition in prairie voles (Microtus ochrogaster), a species characterized by extensive biparental care during the preweaning period. To assess the role of males in parturition and their effect on maternal behavior, we studied parturient behavior of male–female pairs and females recently separated from their mates. We studied 12 births under seminatural conditions. For each birth, we scored behavior beginning with birth of the 1st offspring, using 3 h of continuous videotape records. Time from birth of the 1st offspring to birth of the last was always <1 h. Female prairie voles were aggressive toward their mates and effectively excluded them from the nest for most, if not all, of the period of parturition. Thus, measures of parental behavior were much higher for females than for males in breeding pairs. Females permitted males back into the nest about 1 day after parturition. The behavior at parturition of paired and single females was similar. Our data indicate that females may limit the role of males in parturition and care of newborn young, even in species with extensive paternal investment.

In South American fur seals (Arctocephalus australis) breeding in dense colonies at Punta San Juan, Peru, mothers are regularly separated from pups when they forage at sea throughout lactation and as a result of disturbances among females during on-beach nursing periods. Unattended pups risk injury or death from aggressive females and predatory sea lions, so the ability of mothers and pups to recognize and reunite is an essential component of breeding success. I investigated the relative importance of vocal, visual, olfactory, and spatial cues in the reunion process and examined how these behaviors are related to search context and success. Behavior of 10 tagged mother–pup pairs was recorded during 118 searches, 67% of which resulted in reunion. Mothers and pups appeared to recognize one another by vocal signatures over distance, and mothers used naso-nasal investigation before accepting or rejecting pups. Mothers supplemented their calling behavior with a variety of low-cost strategies such as frequenting a consistent “home spot” (76%), moving about the colony (49%), and investigating approaching pups (42%), but the best predictor of search success was pup response: after pups called and moved toward mothers, pairs were reunited 95% of the time regardless of mothers’ behavior. Pups responded infrequently (18%) to the wrong female, suggesting that pups’ acceptance criteria are conservative when risk of injury from unrelated females is high.

In brown bears (Ursus arctos), nursing of young >1 year of age has a positive effect on their growth rate but is energetically costly for mothers and reduces the number of litters a female can produce during her lifetime. We followed radiomarked families to study their behavior during the period of family breakup. Yearlings separated from their mothers during the mating season and most family breakups were associated with the presence of an adult male, suggesting that termination of maternal care was not initiated by offspring.

The red viscacha rat, Tympanoctomys barrerae, is an octodontid rodent endemic to the Monte and Patagonian deserts of Argentina. It lives in burrows with numerous portals facing different directions. We studied climatic factors as possible determinants of burrow architecture and portal orientation, in 2 populations. Climatic factors examined were sunlight, direction of sun’s rays, and wind frequency and intensity. Variables analyzed for burrow architecture were portal orientation, slope, and depth at the 1st turn. Mean number of portals per burrow was significantly different between populations. Burrows had few portals oriented toward predominantly cold and intense winds. More portals faced direct solar light in winter. Burrows are so constructed as to allow openings to receive direct sunlight in winter and indirect sunlight in summer.

Distances traveled daily by coyotes, Canis latrans, were monitored for 2 years (1990–1991) in an oak–pine forest (Pinus and Quercus) in Durango, Mexico. Fourteen adult coyotes (6 females and 8 males) were trapped, radiocollared, and monitored for 24-h periods during breeding, gestation, pup-rearing, and juvenile independence seasons. Mean distances traveled by day by males (16.47 km) were longer than those traveled by females (12.51 km). Mean distances traveled at night were longer (8.24 km) than distances traveled by day (6.51 km), for both sexes. Females and males traveled similar mean distances by day and by night during seasons of breeding, gestation, and juvenile independence. During the pup-rearing season, however, travel by males and females was predominantly nocturnal. Daily distances traveled by coyotes appear to be determined by energy demands imposed by these biological seasons.

To estimate home range and ascertain nesting habits of golden mice (Ochrotomys nuttalli), 19 individuals were radiocollared and their nests located. Individual home-range area did not significantly vary with sex, season, or number of nests used; minimum convex polygon and adaptive kernel estimates ranged from 0.18 to 1.33 ha and from 0.33 to 2.82 ha, respectively. Home-range overlap among individuals was considerable. No difference existed in distances between nests used by the same individual. Females used more arboreal nests; males used more ground nests. Only males exclusively used ground nests. Significant variables associated with placement of both ground and arboreal nests were distance to nearest vines and undergrowth, densities of herbaceous and woody stems, and density of understory <0.5 m at 1 m from the nest. Depth of leaf litter and size (dbh) of nearest tree also predicted placement of ground nests. Density of understory, 1.6–2.0 m high, and number of herbaceous stems significantly predicted placement of arboreal nests. The golden mouse may be less of a habitat specialist than believed. Management for invasive or early successional plant species may enhance habitat for this species.

Least blossom bats, Macroglossus minimus (Pteropodidae), were monitored by radiotelemetry in lowland rainforest for up to 22 days in Kau Wildlife Area, Madang Province, Papua New Guinea. Based on 1,502 radiotelemetry positions, mean home range for 18 individuals was 5.8 ha ± 4.6 SD, and mean core-use area was 1.5 ± 1.3 ha. The mean long axis of the home ranges was 495 ± 258 m. Activity hotspots were associated with flowering bananas, the primary food resource of least blossom bats at Kau. During the day, M. minimus roosted singly in subcanopy or canopy foliage and showed fidelity to a day-roost area. Mean day-roost area was 0.5 ± 0.4 ha. Adult males appeared to exclude conspecifics from rich, compact feeding territories in primary forest. Overlap in home range occurred primarily in gardens and between subadults and other bats.

We developed a radiotracking system for automatic and continuous data collection, which allows the radiotracking of several animals at the same time. Based on a system controller, 3 fixed antennas, and small-size radiotransmitters (<2 g, 14 by 12 by 4 mm), the system has the capacity to record several individuals continuously at intervals of <5 min. Antennas, positioned at fixed points in the field, forward the signals from tagged animals to the system controller, where data are collected. The coordinates of the individual’s locations are calculated through triangulation on the basis of the angles of incidence from the transmitter signal to each antenna. Transmitters are individually identified by the chronological sequence of their signals. Field tests with Microtus arvalis show the utility of the new technique and possibilities for the system.

Despite evidence of migration in North American tree bats (genera Lasiurus and Lasionycteris), details regarding seasonal movements in these widely distributed species are few. This study attempted to clarify patterns of seasonal distribution by mapping museum occurrence records by month. Monthly changes in the distribution of records indicate seasonal movements of tree bats. Northward migration during spring by Lasiurus cinereus appears to stem from wintering grounds in California and Mexico. During summer, male L. cinereus is mainly distributed in western North America, whereas females dominate samples from eastern regions. Lasiurus borealis winters in southeastern areas and expands its range into more northern regions during warmer months. Seasonal dispersal of Lasiurus blossevillii from California is apparently limited, and it is unclear if this group mixes with others to the south and east. Lasionycteris noctivagans also shows movement at the continental scale, although movements may differ between western and eastern groups. Museum records provide little evidence of major movement by any species between North and South America. Despite inherent biases, museum records are a viable means of investigating bat migration.

Models on the distribution of animals are invaluable in understanding how individuals and, ultimately, populations respond to ecological processes. Rarely, have they been applied to conservation issues at a landscape level. We capitalized on the distribution of a previously unavailable novel food resource, found at the juxtaposition of urban and wildland areas, to test the generality of ideal-free distribution (IFD) models using a mammalian carnivore, the black bear (Ursus americanus). The primary question we addressed was whether an increase in the prevalence of individuals in a geographical region reflects a population increase or a landscape level redistribution. Combining spatial and temporal data sets with empirically obtained information spanning 12–15 years, we contrasted demographic, life-history, and reproductive parameters between individuals at urban–wildland interface (experimental) and wildland (control) areas at the interface of the Sierra Nevada Range and Great Basin Desert in western North America. Bears were expected to respond to natural versus artificially clumped resources according to an IFD model. Evidence only partially supported this idea because individuals in urban areas had densities 3 times the historical values from the same area, sex ratios were 4.25 times more skewed toward males, bears had 30% larger body mass, home ranges were reduced by 90% for males and 70% for females, and bears entered dens significantly later than wildland conspecifics. However, females in urban-interface areas gave birth to 3 times the number of cubs, although only half as many dispersed successfully relative to wildland females. Further, urban-interface females had a higher proportion (0.57) of potential reproductive years, in which they had young, compared with wildland females (0.29). We present evidence suggesting that bears in Nevada and in the Lake Tahoe basin conform primarily to an ideal-despotic distribution model. Our findings on population reallocation, rather than demographic increase, reemphasize how knowledge about correlates of individual performance and distribution over time helps to understand the extent to which humans change ecosystems, whether their actions are intentional or not.

Neotropical felids such as the ocelot (Leopardus pardalis) are secretive, and it is difficult to estimate their populations using conventional methods such as radiotelemetry or sign surveys. We show that recognition of individual ocelots from camera-trapping photographs is possible, and we use camera-trapping results combined with closed population capture–recapture models to estimate density of ocelots in the Brazilian Pantanal. We estimated the area from which animals were camera trapped at 17.71 km². A model with constant capture probability yielded an estimate of 10 independent ocelots in our study area, which translates to a density of 2.82 independent individuals for every 5 km² (SE 1.00).

We monitored European ground squirrels (Spermophilus citellus) in a recreation area near Vienna, Austria, over a 7-year period to follow their population dynamics. Data were obtained by mark–recapture and daily checklists in an attempt to track the fates of individuals present in a defined area. Abundance of nonjuveniles present in spring decreased from 56.0 individuals/ha in 1992 to 6.3 individuals/ha in 1998. Litter size and yearling-male reproduction were inversely related to density, whereas immigration, juvenile survival, and proportions of nonjuvenile males exhibited a positive relationship. We conclude that the study population had been a dispersal sink and that ceasing immigration combined with poor local survival caused the population to crash. The temporal coincidence of these 2 effects indicates an extrinsic factor acting both on residents and potential immigrants.

Forests of Southern Appalachia are critical habitats with respect to biodiversity, with a large portion of these forests residing on public multiuse lands. With pressure to extract timber from maturing forests, there is a need to identify the relative importance of forest types within the larger forest matrix. We examined small-mammal populations at 350 sample points across 157 km² of forested habitat in the George Washington and Jefferson National Forests, Virginia, to determine landscape and habitat correlates of species abundance and richness. A total of 3,955 individuals representing 20 species were captured using live trap and pitfall sampling at each point during 1996 and 1997. Nine species were sufficiently common to examine their abundance relative to landscape and habitat features. We found species abundance and richness to be highest in mesic deciduous forest types, with the exception of Peromyscus leucopus. Soil moisture capacity and the proportion of mesic habitat within 100 m of the sample point were also important for several species. If mesic deciduous forest can be considered patches within a matrix of xeric forest, then the abundance of 4 species and species richness could be predicted based on the distance of the sample point to the nearest mesic patch and the abundance of 3 species inside mesic patches was related to patch size. At least 73% of mesic patches within this forest were <25 ha and separated from other patches by >100 m. Our results indicate that mesic forest patches contain the bulk of the species richness for small mammals in the Southern Appalachian ecotype. Designing timber harvests that minimize use of mesic deciduous forest type and that does not decrease patch numbers would achieve the largest benefits to small mammals within the region.

Effects of plateau zokors (Myospalax fontanierii) on seasonal above- and belowground plant biomass, plant species diversity, and soil moisture and organic matter were examined at an alpine meadow site in Qinghai Province, People’s Republic of China. Above- and belowground biomass increased significantly in areas where zokors were removed or burrow systems were abandoned for 5 years compared with areas that zokors had occupied for >10 years. Biomass of monocotyledons was reduced greatly, but biomass of nonpalatable dicotyledons increased significantly, in occupied areas. Diversity of dicotyledons, monocotyledons, and total plants in unoccupied areas was significantly greater than in occupied or abandoned areas. Vegetation cover and height in occupied areas were significantly less than in unoccupied and abandoned areas. No consistent effect by zokors on soil moisture and organic matter was observed.

Our aim was to study selective owl predation on size and sex classes of rodents in northwestern Argentine Patagonia and to determine which behavioral traits may be involved in differential prey vulnerability. Diet of Magellanic horned owls (Bubo magellanicus) was studied for 2 years. Jaw and pelvic measurements were used to estimate size and sex of rodents eaten by owls. Livetrapping of rodents was conducted simultaneously with diet analysis to estimate proportion of size and sex classes of rodents available and to examine movement and microhabitat use. Owls generally selected individuals of smaller size and avoided heavier individuals. Sex classes of prey were consumed according to availability, except that the female silky desert mouse (Eligmodontia morgani) was selected. Smaller individuals of E. morgani, the long-haired mouse (Akodon longipilis), and the yellow-nosed mouse (A. xanthorhinus) tended to use open microhabitat where risk of predation was higher. Vulnerability to predation seemed to be related to differential activity and use of microhabitat.

The relationship between body size and rumen–reticulum capacity among conspecific individuals is predicted to be isometric. We examined whether the relationship between body weight and rumen–reticulum capacity was isometric in adult male and female tule elk (Cervus elaphus nannodes) and in adult female mule deer (Odocoileus hemionus). We detected no effect of sex on this relationship in elk, and the slope of the regression was 1.0 for one measure of rumen–reticulum capacity and <1.0 for another. Among deer, the slope of the relationship was <1.0 in one measure of rumen–reticulum capacity, and we detected no relationship with the other.

Skull morphometry of 206 stranded juvenile and adult bottlenose dolphins (Tursiops truncatus) from Texas and Florida were examined. Juveniles differed significantly from adults in both Texas and Florida populations. Sexual dimorphism was present in skulls from Texas but not from Florida. Regional differences in females from Texas and Florida were apparent, especially in braincase height, whereas male bottlenose dolphins did not differ between regions. Females could be distinguished accurately to region (90% classification success) using skull morphometry. Cranial morphometrics of T. truncatus are concrete values that may aid in identification of a type specimen for each population. Furthermore, these results can be used as a standard for Tursiops in the Gulf of Mexico.

We examined morphological variability and evolution of the baculum (os penis) across the Mustelidae through allometric analyses and character mapping. Fifty-four species and 26 genera (including 2 fossil forms) were examined with numerous caniform out-group species. Allometric analyses showed that bacular length is relatively constant across mustelids and caniforms; only a tendency to a slightly shortened baculum in mephitines was observed. Character mapping revealed the ancestral mustelid baculum to be an elongated rod-shaped bone that lacks a urethral groove and possesses a simple, nondistinct distal tip. This form is largely retained in mephitines and, to a lesser degree, in lutrines. From the ancestral condition, it is possible to derive forms with a more complicated head that has projections and openings (e.g., melines, Eira barbara, Galictis, Gulo gulo, Martes) or spoon-shaped and cup-shaped processes (e.g., Ictonyx, Mellivora capensis). Another evolutionary trajectory involves the distal tip of the baculum becoming hook-shaped and the urethral groove well developed (e.g., Mustela, Vormela peregusna). Although the structure of the baculum distinguishes closely related species, many features are derived independently in more distantly related forms. Therefore, bacular structure provides restricted phylogenetic information and should be analyzed in concert with other data sources (e.g., morphology of the basicranial region).

In the 1950s and 1960s, translocation projects reintroduced black bears (Ursus americanus) from Minnesota and Manitoba to Arkansas and Louisiana. Today, several geographically disconnected populations exist in Arkansas and Louisiana, but their origins are unclear. Some populations may represent a separate subspecies, U. a. luteolus, which is federally protected. We characterized 5 microsatellite loci in 5 isolated populations in Arkansas and Louisiana and compared them with genotypes from Minnesota. Our data indicate that bears of the Ozark and Ouachita mountains of Arkansas, an inland area of Louisiana, and those of Minnesota are similar in overall genetic diversity and allele frequencies, consistent with these populations being wholly or mostly descended from bears from the reintroduction programs. In contrast, bears from southeastern Arkansas and the coastal region of Louisiana genetically are more restricted and homogeneous. Because they exhibit a limited set of genotypes found in the other black bear populations, they represent isolated fragments of a single North American black bear population. Furthermore, genetic distance estimates indicate that the bears in southeastern Arkansas are more genetically distinct from bears in Louisiana, which are currently federally protected.

Although generally limited to coastal waters of South America, South Africa, and New Zealand, dusky dolphins (Lagenorhynchus obscurus) show high potential for dispersal over large distances. In New Zealand, photographic identification data indicate a seasonal shift in residency of dolphins between Kaikoura and the Marlborough Sounds as well as changes in group size and behavior. The effect of this seasonal variation on the genetic structure of New Zealand’s dusky dolphins was examined by sequencing a 473–base pair fragment of the mitochondrial DNA control region for 169 individuals from 4 regions along the New Zealand coast. A neighbor-joining phylogeny and an analysis of molecular variance did not support genetic subdivision among regions (ϕ_sr = −0.041, P = 0.13). However, nested-clade analysis demonstrated significant evidence for contiguous range expansion and fragmentation along the New Zealand coast. Seasonal movement patterns from Kaikoura to either Otago or the Marlborough Sounds and West Coast are presented as an alternative explanation of nested clade results. New Zealand–wide diversity indices and rate of substitution among sites were used to estimate effective female population size. Lineages-through-time analysis was used to test hypotheses of population growth. Structure of the neighbor-joining phylogeny, the nested haplotype network, and results of the lineages-through-time analysis suggest that the New Zealand dusky dolphin population underwent at least 1, if not 2, historical population expansions.

Nucleotide variation was assessed from the mitochondrial control region of North American moose (Alces alces) to test predictions of a model of range expansion by stepping-stone dispersal and to determine whether patterns of genetic variation support the current recognition of 4 subspecies. Haplotypes formed a star phylogeny indicative of a recent expansion of populations. Values of nucleotide and haplotype diversity were low continent-wide but were greatest in the central part of the continent and lowest in peripheral populations. Despite low mitochondrial diversity, moose exhibited a high degree of differentiation regionally, which was not explained by isolation by distance. Our data indicate a pattern of colonization consistent with a large central population that supplied founders to peripheral populations (other than Alaska), perhaps through rare, long-distance dispersal events (leptokurtic dispersal) rather than mass dispersal by a stepping-stone model. The colonization scenario does not account for the low haplotype diversity observed in Alaska, which may be derived from a postcolonization bottleneck. Establishment of peripheral populations by leptokurtic dispersal and subsequent local adaptation may have been sufficient for development of morphological differentiation among extant subspecies.

We describe a new extinct genus and species of bat belonging to the endemic Neotropical family Natalidae (Chiroptera) from the Thomas Farm Local Fauna in northern peninsular Florida of early Miocene age (18–19 million years old). The natalid sample from Thomas Farm consists of 32 fossils, including a maxillary fragment, periotics, partial dentaries, isolated teeth, humeri, and radii. A proximal radius of an indeterminate natalid is reported from the I-75 Local Fauna of early Oligocene age (about 30 million years old), also from northern Florida. These fossils from paleokarst deposits in Florida represent the 1st Tertiary records of the Natalidae. Other extinct Tertiary genera previously referred to the Natalidae, including Ageina, Chadronycteris, Chamtwaria, Honrovits, and Stehlinia, may belong to the superfamily Nataloidea but do not fit within our restricted definition of this family. Eight derived characters of the Natalidae sensu stricto are discussed, 5 of which are present in the new Miocene genus. Intrafamilial phylogenetic analysis by parsimony of the Natalidae suggests that the 3 living subgenera, Natalus (including N. major, N. stramineus, and N. tumidirostris), Chilonatalus (including C. micropus and C. tumidifrons), and Nyctiellus (including N. lepidus), deserve full generic rank. The Natalidae apparently evolved in North America before the late Oligocene, went extinct in what is now the Nearctic region (i.e., Florida) after the early Miocene, and survived in tropical Middle America during the remainder of the Tertiary. The presence of 2 endemic genera and 4 endemic species suggests that natalids reached the West Indies by overwater dispersal early in their history (Oligocene or Miocene). The lack of a Tertiary fossil record, marginal distribution, and limited species richness and endemism of natalids in South America are suggestive of a comparatively late arrival on that continent, possibly in the late Pliocene after the beginning of the Great American Faunal Interchange.

Pappogeomys alcorni is a peripherally isolated species that currently is designated as a rare species in Mexico. There are only 4 known museum specimens, all collected between the years 1950 and 1966, and recent attempts have failed to locate individuals in the wild. Although only 1 new specimen (skin only) has been collected since the original systematic work on P. alcorni, new analytical methods permit reexamination of existing specimens. DNA was isolated from a 48-year-old museum skin to investigate the phylogenetic relationship of this rare taxon to other species of Pappogeomys and Cratogeomys. Phylogenetic analysis based on 424 base pairs of the mitochondrial cytochrome-b gene and morphometric analysis of 101 individuals of Pappogeomys indicate that P. alcorni is a geographically disjunct subspecies of P. bulleri rather than a monotypic species.