This paper is based on an oral presentation delivered at the 89th Annual Meeting of the American Society of Mammalogists in Fairbanks, Alaska on 25 June 2009, where I was honored to receive the Society's Joseph Grinnell Award for excellence in education in mammalogy. The motivation for the topic of my presentation was the many “bad” talks all of us have endured at scientific meetings and in other situations. As I do for undergraduate and graduate classes, rather than providing a list of seminar “dos” and “don'ts,” I presented a practical demonstration of many of the “don'ts” I have observed and then attempted to present the same information incorporating as many of the “do's” as I could. In other words, I delivered a bad and then a good version of the same presentation. My goal was to provide the audience with advice that would be useful when presenting information about mammals to scientific colleagues and the general public (e.g., service clubs or school groups). Given that it is impossible to recreate aspects of my performance using the written word, my purpose here is to summarize my opinions about the key elements of good talks. The goal of a talk should be to maximize the likelihood that it will be perceived as interesting, thoughtful, and purposeful and that the key take-home message(s) will be understood and remembered. It is my strongly held belief, especially with the now essentially universal use of computer slideware (e.g., PowerPoint), that an opportunity exists to enhance the usefulness of oral presentations but a real risk of muddling them to the point where the intended message is lost. I also make some recommendations about how to avoid common pitfalls of using this software.

The systematics and phylogeography of the San Diego pocket mouse (Chaetodipus fallax), a species restricted to the Baja California Peninsula and adjacent southwestern California, were assessed using sequences of the mitochondrial cytochrome-b gene (Cytb). Genetic relationships were evaluated among the 6 recognized subspecies of C. fallax (including the island population, C. f. anthonyi) in 3 geographic regions from individuals representing 22 populations. Analysis of molecular variance and multiple phylogenetic analyses indicated 3 main clades: northern populations in the southwestern Mojave Desert and Los Angeles Basin north of the Salton Trough; central populations from south of the Salton Trough and throughout the state of Baja California; and southern populations from west of the Vizcaíno Desert in Baja California Sur and adjacent Isla Cedros. These clades do not correspond to the currently recognized subspecies, and each could be considered a distinct subspecies pending analysis of nuclear DNA or characters (e.g., morphology) encoded by nuclear DNA.

The red viscacha rat, Tympanoctomys barrerae, is an octodontid rodent endemic to the arid west-central and southern regions of Argentina. It is solitary, lives in complex burrows built in soft soil, and occurs at low population densities in patches associated with salt basins and sand dunes in lowland habitats of the Monte and Patagonia deserts. The purpose of this study was to investigate the genetic structure and biogeography of this desert specialist. To assess genetic variation an 800-base pair fragment of the mitochondrial control region was sequenced for 60 individuals from 8 localities across the species' range. Relationships among haplotypes were inferred from phylogenetic analyses (maximum parsimony, Bayesian, and networks). Genetic structure and demographic history were analyzed with descriptive statistics, mismatch distributions, neutrality tests (Tajima's and Fu's), and analyses of molecular variance (AMOVAs). In total, 26 haplotypes were found, most restricted to single populations. The presence of unshared haplotypes was consistent with low migration rates. Within the distribution (between 29°S and 39°S) southern and northern populations showed higher genetic diversity values than central populations. Populations of T. barrerae showed moderate to high genetic differentiation on the basis of haplotypes of central populations. AMOVA analyses indicated a moderate level of geographic structure for all populations. Low haplotype and nucleotide diversities in central populations suggest a possible bottleneck associated with Pleistocene glaciations or volcanic activity in this part of the range of the viscacha rat. Phylogeographic structure was moderate, and the analyses recovered 2 principal clades: A (with central and a part of the southern distribution) and B (with northern and another part of the southern distribution). Most populations were polyphyletic, indicating that they have not been isolated long enough to reach reciprocal monophyly. Demographic analyses conducted for clades A and B suggest a recent history of population expansion.

The Texas mouse, Peromyscus attwateri, is a relatively habitat-specific species that exhibits a discontinuous distribution across the south-central United States. To examine the evolutionary history and contemporary population genetic structure of P. attwateri we sequenced an 1,100-base pair fragment of the mitochondrial cytochrome b gene for 210 individuals from 22 localities, resulting in 89 unique haplotypes. Low nucleotide diversity (π  =  0.0043) and a median-joining haplotype network indicated low levels of divergence among haplotypes with little geographic structure. Demographic analyses indicated the presence of 2 significant range expansions: the 1st coinciding with the end of the last glacial maximum of the Pleistocene approximately 14 thousand years ago (kya) and the 2nd more recent expansion during the hypsithermal (9–5 kya) of the Holocene. Coalescent simulations under a model of no gene flow indicated that the lack of divergence among populations most likely is attributable to incomplete lineage sorting, and the observed gene flow statistic (s  =  116) suggests that populations became isolated approximately 7.5 kya. This finding substantiates the hypothesis that the thermal maximum of the hypsithermal may have had a significant impact on small mammals as well as other organisms in the south-central United States.

Fragmentation of wildlife populations can have detrimental effects, including genetic differentiation of populations, loss of genetic diversity, and inbreeding depression. We evaluated the genetic structure among isolated colonies of black-tailed prairie dogs (Cynomys ludovicianus) along an urban gradient in southern Denver, Colorado. Urban colonies are important ecologically and for educational purposes, and they serve as source populations for relocation efforts. Levels of genetic differentiation between colonies were high relative to colonies in natural habitat at comparable or greater distances. Prairie dog colonies depend on dispersal among colonies for long-term persistence, and we found evidence for reduced but measurable rates of movement of individual prairie dogs among urban fragments. We observed a trend for smaller and more isolated colonies to exhibit lower genetic diversity, but we did not detect inbreeding in any of the colonies sampled. Isolation-by-distance measures, including measures based on permeability of various features of urban habitat such as roads and development, did not explain genetic differences. Our system represents a possible end point in the genetic consequences of continued loss and isolation of prairie dog colonies as fragmentation increases in both urban and natural landscapes. Urban development could affect dispersal in unexpected and complex ways and requires further study, but prairie dog colonies and their associated wildlife communities in urban areas have the potential for long-term persistence if not extirpated by human activity.

Nucleotide sequences from 94 individuals representing the Oryzomys palustris complex (O. palustris and O. couesi) were examined to assess phylogenetic relationships and taxonomic boundaries. Sequence data from the entire mitochondrial cytochrome-b (Cytb; 1,143 base pairs [bp]), a portion of exon 1 of the nuclear interphotoreceptor retinoid-binding protein (1,266 bp), and intron 2 of the alcohol dehydrogenase 1 (580 bp) genes were analyzed using phylogenetic methods (maximum parsimony and Bayesian inference). In the Cytb analysis, individuals recognized as O. palustris and O. couesi formed reciprocally monophyletic clades supporting their recognition as species; however, additional phylogenetically informative groups were present within each of the 2 nominate clades. In addition, levels of genetic divergence within the currently recognized taxa exceeded values normally associated with intraspecies variation. Together, the phylogenetic and genetic divergence data imply that consideration should be given to recognizing 4 additional species in this complex.

We investigated the evolutionary history of a group of silky pocket mice (Heteromyidae: Perognathinae: Perognathus flavus species group) composed of the species P. flavus and P. merriami to determine patterns and postulate causes of geographical diversification across arid grasslands and intermontane basins in western North America. The region represents a topographically complex landscape with a Neogene history of dramatic geological and climatic transformations. Phylogenetic and dating analyses of mitochondrial DNA support an initial split among 4 major lineages during the late Miocene, and this hypothesis receives further support from analysis of a portion of the nuclear interphotoreceptor retinoid-binding protein (IRBP) gene. Two of these lineages have a restricted geographic distribution in the Chihuahuan Desert, and 2 have distributions ranging across large portions of the Chihuahuan Desert, Colorado Plateau, Great Plains, and Tamaulipan Plain. Within the 2 widespread lineages further geographical diversification likely was concentrated in the Pliocene, which coincided with the origin of several hypothesized geographic barriers. These results are consistent with models of allopatric divergence driven by pre-Pleistocene geological and climatic events, particularly the late-Miocene expansion of interior grasslands and Miocene–Pliocene evolution of Basin and Range geomorphology. Therefore, the biogeographic structure displayed in the flavus species group may be predictive for a range of sympatric taxa.

Glacial cycles in the late Pleistocene played a dominant role in sculpting the evolutionary histories of many high-latitude organisms. The refugial hypothesis argues that populations retracted during glacial maxima and were isolated in separate refugia. One prediction of this hypothesis is that populations inhabiting different refugia diverged and then, during interglacial periods, rapidly expanded into deglaciated regions. The range of the gray wolf (Canis lupus) was modified by these expansion and contraction cycles in the late Pleistocene. Our analyses of variation of mitochondrial control region sequences corroborate previous microsatellite analyses supporting independent evolutionary histories for Coastal and Continental wolves in North America. Coastal wolves represent the remnants of a formerly widespread and diverse southern clade that expanded into coastal Southeast Alaska, likely in the early Holocene. In contrast, extant northern Continental populations appear to be admixed, composed of lineages independently arising from ancestors that persisted in either southern or northern (Beringia) refugia. This pattern of diversification suggests the possibility of 3 temporally independent colonizations of North America by wolves from Asia. Coastal wolves are the last vestige of a formerly widespread phylogroup that largely was extirpated in North America by humans during the last century. The independent phylogeographic history of these Coastal wolves has yet to be characterized. Their distinctiveness among North American wolf populations may warrant a reevaluation of their conservation status and management.

Dinaric–Balkan and Carpathian gray wolf (Canis lupus L., 1758) populations, although geographically separated, occupy closely situated areas in the territory of Serbia. We studied morphological variation in the skull to investigate whether the two populations are distinguishable despite the animals being very large and highly mobile and seeming to form one continuous population. The size and shape of the mandible and cranium in the lateral view were compared between sexes and populations using landmark-based geometric morphometrics. Significant differences between sexes and populations were found for size and shape of both structures. Males were larger than females in both populations, and Carpathian were larger than Dinaric–Balkan wolves. Principal component analysis revealed the cranium to be a highly discriminative skull structure. Zygomatic arches were located anteriorly in males and posteriorly in females. Dinaric–Balkan wolves had a more elevated snout and sagittal crest than Carpathian wolves. Difference between Dinaric–Balkan and Carpathian wolves in the cranial flexion was observed for the first time in a comparative study of wolf populations. Present-day separation of Dinaric–Balkan and Carpathian wolf populations could have originated from 2 different glacial refuges. We presume that the observed morphometric divergence between the populations is not only a relic of the last glacial maximum but was further strengthened and shaped by synergistic effects of environmental factors and social behavior (territoriality and a dispersal mechanism influenced by the natal habitat).

A new species of Akodon (sigmodontine rodents of the tribe Akodontini) is described from the Córdoba Montane Savanna Ecoregion in the eastern mountain ranges of the Sierras Centrales in central Argentina. Phylogenetic relationships among the new species and 11 other species of Akodon were examined using nucleotide sequence data from the entire 1,140 base pairs of the mitochondrial cytochrome-b gene. Maximum-parsimony, maximum-likelihood, and Bayesian analyses found the new species to be distinct from other Akodon and sister to a clade composed of A. spegazzinii, A. boliviensis, and A. oenos. We present analyses of morphological data and descriptions of external, cranial, and dental morphology. This species is relevant to the insular biogeography of the Sierras Centrales, the uniqueness of the ecoregion, and the level of plant and animal endemism in isolated montane regions of central Argentina.

Historically, a large number of taxonomic forms has been recognized within Nearctic pikas (Lagomorpha: Ochotonidae; Ochotona), including up to 13 species and 37 subspecies. After 1965, 2 species and 37 forms have been recognized: the monotypic O. collaris of Alaska, British Columbia, Yukon, and Northwest Territories, and O. princeps, with 36 subspecies spread throughout western Canada and the western United States. The 36 subspecies of O. princeps have been distinguished by subtle differences, particularly in pelage coloration and body size, within the highly fragmented distribution of the species on isolated “islands” of cool, rocky habitat. However, molecular phylogenetic studies (allozyme electrophoresis and sequencing of both mitochondrial and nuclear genomes) indicate the existence of 5 phylogenetic lineages within O. princeps. The cohesiveness of each lineage has been reinforced during glacial stages by introgressive hybridization among currently isolated populations within each lineage. In contrast, the low level of cranial variation and lack of consistent differentiation in cranial characters, pelage coloration, or body size among the 5 lineages indicates idiosyncratic interlocality variation due to high inbreeding within highly isolated populations, genetic drift, and possibly selection for common traits. Examination of allozymic, morphological, and nuclear DNA data indicates previous introgressive hybridization among several of the lineages, probably associated with contact during the Last Glacial Maximum. Herein we characterize morphometric variation between and among O. collaris (n  =  164) and O. princeps (n  =  1,999) and revise the subspecific taxonomy of O. princeps to 5 subspecies based on molecular phylogenetic lineages, at least 3 of which are known to possess a unique dialect in the short call: O. p. princeps (Northern Rocky Mountains), O. p. fenisex (Coast Mountains and Cascade Range), O. p. saxatilis (Southern Rocky Mountains), O. p. schisticeps (Sierra Nevada and Great Basin), and O. p. uinta (Uinta Mountains and Wasatch Range of central Utah). These 5 subspecies represent evolutionarily meaningful units for consideration of possible management applications if populations of O. princeps are imperiled by human activities.

We used mark–recapture estimation techniques and radiography to test hypotheses about 3 important aspects of recruitment in big brown bats (Eptesicus fuscus) in Fort Collins, Colorado: adult breeding probabilities, litter size, and 1st-year survival of young. We marked 2,968 females with passive integrated transponder (PIT) tags at multiple sites during 2001–2005 and based our assessments on direct recaptures (breeding probabilities) and passive detection with automated PIT tag readers (1st-year survival). We interpreted our data in relation to hypotheses regarding demographic influences of bat age, roost, and effects of years with unusual environmental conditions: extreme drought (2002) and arrival of a West Nile virus epizootic (2003). Conditional breeding probabilities at 6 roosts sampled in 2002–2005 were estimated as 0.64 (95% confidence interval [95% CI]  =  0.53–0.73) in 1-year-old females, but were consistently high (95% CI  =  0.94–0.96) and did not vary by roost, year, or prior year breeding status in older adults. Mean litter size was 1.11 (95% CI  =  1.05–1.17), based on examination of 112 pregnant females by radiography. Litter size was not higher in older or larger females and was similar to results of other studies in western North America despite wide variation in latitude. First-year survival was estimated as 0.67 (95% CI  =  0.61–0.73) for weaned females at 5 maternity roosts over 5 consecutive years, was lower than adult survival (0.79; 95% CI  =  0.77–0.81), and varied by roost. Based on model selection criteria, strong evidence exists for complex roost and year effects on 1st-year survival. First-year survival was lowest in bats born during the drought year. Juvenile females that did not return to roosts as 1-year-olds had lower body condition indices in late summer of their natal year than those known to survive.

The reproductive cycle of mammals can be inhibited by 2 factors, seasonal breeding and dominance control, both potentially important in mole-rats. The gonads and gonadal steroids of dominant (reproductive) and subordinate (nonreproductive) Natal mole-rats (Cryptomys hottentotus natalensis) were investigated to determine the effects of season and social status on reproduction within natal colonies. We found no seasonal differences in concentrations of gonadal steroids of male or female mole-rats. Similarly, the gonadal histology and volume showed no seasonal differences. These results, together with the presence of fetuses, confirm the potential for breeding throughout the year. Reproductive and nonreproductive mole-rats display comparable testosterone and estrogen concentrations in males and females, respectively. Follicular development and the presence and number of sperm in nonreproductive animals suggest that the reproductive quiescence in nonreproductive animals is likely to result from behavioral interference of dominant animals or incest avoidance (or both). Urinary progesterone concentrations of reproductive females were significantly higher than those of nonreproductive females. Although follicular development in nonreproductive females proceeds to the level of Graafian follicles, the number of these follicles present in nonreproductive females was significantly less than that in reproductive females. The reproductive physiology of the Natal mole-rat compares with other loosely social mole-rat species inhabiting mesic areas.

Relatively little is known about the mating behavior, and factors that influence the mating behavior, of socially monogamous mammals. We used a combination of behavioral and genetic data to examine the mating tactics of a socially monogamous population of bat-eared foxes (Otocyon megalotis). In contrast to some other canid species, we found no evidence that either sex increased range size or traveling distance during the mating season, demonstrating that neither sex roams widely in pursuit of extrapair copulations. Mated partners maintained close proximity during, and sometimes outside, the mating season, suggesting that females looking to engage with extrapair mates might find it difficult to do so. Consistent with these findings, microsatellite analyses revealed lower levels of extrapair paternity (EPP) than have been reported in other canid species, with only 9.8% of cubs produced outside of the pair-bond. We suggest that the relatively low level of EPP in the bat-eared fox may be influenced partly by diet and foraging behavior, which makes it easy for males to maintain close proximity to partners and costly for either sex to roam in search of extrapair mates.

The biodiversity of piñon–juniper (P-J) woodlands of western North America has received increasing attention from conservationists because of concerns about woodland invasion into adjacent shrub-steppe communities. Small mammals contribute substantially to the faunal diversity of P-J woodlands, but the responses of small mammals to the inherent structural complexity of these woodlands have not been well described. We used occupancy modeling and ordination to describe habitat selection along a woodland–savannah gradient of 4 species of rodents, including 2 putative P-J woodland specialists, Peromyscus truei and Tamias dorsalis. We accounted for the influences of season and prior conspecific capture on detectability. P. truei and T. dorsalis preferred old-growth woodland sites near rock outcrops with high canopy and bare-ground cover and low herb and shrub cover. Tamias minimus preferred savannah sites with high shrub and grass cover farther from rock outcrops. We found no evidence of resource selection along the gradient by Perognathus parvus. Our results provide insight into the role of habitat selection in facilitating coexistence among closely related species within P-J woodlands and suggest that management efforts that better discriminate between old, presettlement stands and young, invasive stands may enhance regional biodiversity. We demonstrate an effective application of occupancy modeling for describing habitat selection of cryptic rodents, which are particularly prone to imperfect detection.

Both breeding activity and abundance and quality of available food are expected to influence daily movements of animals. Animals are predicted to range over large areas to meet high energy demands associated with reproduction (females) or to increase mating success (males). However, animals should expand their range areas whenever food conditions deteriorate. To examine the extent to which breeding activity versus food availability influence space use, we compared the size and location of range areas (home ranges) of the degu (Octodon degus), a diurnal rodent from semiarid environments of north-central Chile, during the austral winter and summer seasons. Degus produce young during the austral spring (September–October) when high-quality food is readily available. In contrast, degus do not breed during the austral summer (January–March) when food is scarce and of low quality. We predicted that degus would range over smaller areas in winter if the availability of food has a greater influence on space than breeding activity. Individuals were radiotracked in winter and the following summer over a 3-year period. Surveys of herbaceous cover were conducted during winter and summer to determine seasonal changes in the abundance and quality of primary food. In summer degus expanded and moved the location of their range areas to locations with available food. Given that preferred food was less abundant in summer than winter, we suggest that degu range areas are strongly influenced by food conditions.

Relatively little information is available concerning the natural history or population ecology of the montane akodont, Akodon montensis, a sigmodontine species that harbors Jaborá and Ape Aime hantaviruses. On the basis of mark-recapture sampling of 3 locales during 2 years, this report provides comparative data on populational and other characteristics of the species near its distributional limit, in the Upper Paraná Atlantic Forest in Paraguay. We found A. montensis to be almost exclusively terrestrial (nonarboreal) and to vary in population density among locales and between years, findings consistent with earlier studies. Population density was not related either to neotropical seasonality or to most precipitation variables, but sex ratio varied seasonally, which has not been reported previously. We evaluated the seroprevalence of hantavirus in A. montensis, in association with external, populational, and individual variables. As in most previous studies of rodent–hantavirus systems, seroprevalence varied among sampling locales and was higher among males. However, unlike previous reports, especially those from North America, we did not find a correspondence between seroprevalence and population density, seasonal variation, or most precipitation variables. Simple and direct associations between seroprevalence levels and either seasonality or precipitation may be less characteristic of humid neotropical or subtropical systems. Our analyses revealed that seropositive animals exhibit several noteworthy behavioral and life-history modifications, in particular that they have larger home ranges than do seronegatives; exhibit greater maximum distance moved; have greater home range displacement between sampling sessions, particularly those individuals that are seroconverting during the same period; and have greater longevity, especially among males. In general, these characteristics could be postulated as favorable to the capacity of the virus to be transmitted horizontally to other hosts.

Trap–neuter–release (TNR) programs, in which feral cats are sterilized and fed in unconfined colonies, have been advocated as a humane and effective way to reduce the impacts of feral cats on native wildlife. Little is known, however, about the effects of sterilization on feral cat movements and space use, particularly where colonies are located near natural areas. We determined home-range area and overlap and characterized the long-range movements of 14 sterilized and 13 intact radiocollared cats on Catalina Island, California, from 2002 to 2004. Male home ranges were significantly larger than those of females, but no significant differences were revealed in home-range areas or overlap between sterilized and intact cats. Cats regularly moved between natural habitats in the interior of the island and human-populated areas regardless of sex or treatment status, although most (68%; 17/25) of the cats that moved long distances were female. Island-wide, the cat population was estimated to be 600–750 cats, with >70% associated with developed areas, including existing TNR colonies. The influx of subsidized cats to natural habitats, combined with their high vagility and low trappability, makes TNR an unlikely solution for controlling feral cats on a large, rugged island like Catalina and, more generally, in other locations where human populations abut ecologically sensitive areas.

Investigations into mechanisms of resource partitioning are particularly suited to systems where nascent interactive behaviors are observable. Wolf (Canis lupus) recolonization of the Greater Yellowstone Ecosystem provided such a system, and we were able to identify behaviors influencing the partitioning of resources by coyotes (Canis latrans) and wolves. We observed coyote–wolf interactions immediately after wolf recolonization, when reemergent behaviors mediating the outcome of competitive interactions were detectable and mechanisms of spatial avoidance were identifiable. Although coyotes used the same space as wolves, they likely minimized risk of encounter by making adaptive changes in resource selection based on perception of wolf activity and potential scavenging opportunities. When exploiting carrion subsidies (i.e., wolf-killed ungulates), coyotes relied on social behaviors (i.e., numerical advantage in concert with heightened aggression) to mitigate escalating risk from wolves and increase resource-holding potential. By adapting behaviors to fluctuating risk, coyotes might reduce the amplitude of competitive asymmetries. We concluded coyotes do not perceive wolves as a threat requiring generalized spatial avoidance. Rather, the threat of aggressive interactions with wolves is spatially discrete and primarily contained to areas adjacent to carrion resources.

Small mammals in boreal forest ecosystems fluctuate dramatically in abundance and 1 possible mechanism to explain these changes is the bottom-up hypothesis of variation in food supplies. Here we ask if variation in berry crops produced by 6 major species of dwarf shrubs and herbs, epigeous mushroom crops, and white spruce seeds allow us to predict changes in the abundance of the red-backed vole (Myodes [ =  Clethrionomys] rutilus), the deer mouse (Peromyscus maniculatus), and field voles (Microtus oeconomus and M. pennsylvanicus combined) over 13 years (1997–2009) in the Kluane Lake region of the southwestern Yukon, Canada. M. rutilus is the dominant rodent in these forests, comprising 64% of the catch. Overwinter survival is a key demographic variable in all these rodents, and the winter food supply—principally berries produced the previous summer—may be 1 key to overwinter survival. We predicted that berry, mushroom, and tree seed crops in year t would produce changes in rodent density in year t 1. We could explain statistically 78–98% of the variation in May and August abundance of all 3 rodent species with indices of berry crops and mushrooms in the previous summer. For M. rutilus the critical predictor was berry crops of Empetrum nigrum. For P. maniculatus, the critical species were Arctostaphylos uva-ursi, A. rubra, and mushrooms. Spruce seed crops were not significantly correlated with rodent densities or changes in density. A large fraction of the variation in rodent numbers in this ecosystem is explained by a simple bottom-up model of population limitation.

Recovery of the Australian fur seal (Arctocephalus pusillus doriferus) population has been slower than that of other fur seals, perhaps due to nutritional constraints on fecundity. However, the population doubled in recent decades, suggesting that reproductive rates may have changed. Pregnancy rates and birthrates were estimated and the influences of maternal age, size, condition, and lactation status were investigated over 3 consecutive breeding seasons (2003–2005). Mid-gestation pregnancy rate, estimated from plasma progesterone concentrations, was 84% ± 3% (mean ± SE) and was negatively influenced only by age (P < 0.001). Birthrate, estimated from observations of females with newborn offspring during the breeding season, was 53% ± 3% (mean ± SE) and was influenced negatively by lactation status (P  =  0.035). The difference between pregnancy rates and birthrates suggests that a high degree of late-gestation abortion occurs, especially in younger females. Lactation status was not influenced by any variables, and the high rate (86% ± 2%; mean ± SE) suggests that many offspring are suckled beyond the typical weaning period. Although relationships between reproductive rates and body condition were not found, the results are consistent with a nutritional stress hypothesis. The recent increase in population growth is not due to increased fecundity, which remains low compared to other otariids. Paradoxically, high pregnancy rates were observed in young females (3 years), suggesting that rapid maturity is adaptive for benthic foragers.

Herpetofauna populations are decreasing worldwide, and the range of wild pigs (Sus scrofa) is expanding. Depredation of threatened reptile and amphibian populations by wild pigs could be substantial. By understanding depredation characteristics and rates, more resources can be directed toward controlling populations of wild pigs coincident with threatened or endangered herpetofauna populations. From April 2005 to March 2006 we used firearms to collect wild pigs (n  =  68) and examined stomach content for reptiles and amphibians. We found 64 individual reptiles and amphibians, composed of 5 different species, that were consumed by wild pigs during an estimated 254 hours of foraging. Primarily arboreal species (e.g., Anolis carolinensis) became more vulnerable to depredation when temperatures were low and they sought thermal shelter. Other species (e.g., Scaphiopus holbrookii) that exhibit mass terrestrial migrations during the breeding season also faced increased vulnerability to depredation by wild pigs. Results suggest that wild pigs are opportunistic consumers that can exploit and potentially have a negative impact on species with particular life-history characteristics.