This Special Feature highlights the diversity of social systems in the South American caviomorph (New World hystricognath) rodents. It includes 3 single-species accounts, 2 reviews of broad taxomomic groups, and 2 synthetic reviews with suggestions for directions for future research.

Among fossorial rodents burrow sharing is an important behavioral attribute that provides the foundation for multiple aspects of social structure. Within the family Echimyidae the torch-tail spiny rat (Trinomys yonenagae) is distinguished from closely related taxa by its tendency to live in burrows in desert habitats. Preliminary field studies have suggested that burrow systems of this species are shared by multiple adults. To test this hypothesis we used livetrapping and radiotelemetry to quantify patterns of burrow use in a population of torch-tail spiny rats located near Ibiraba, Bahia State, Brazil. Examination of our data indicates that 76.2% of 67 burrow systems monitored were occupied by >1 adult, including same-sex pairs, male–female pairs, and multiple adults of both sexes. Spatial overlap among adults captured in the same cluster of burrow entrances was extensive (72.0% ± 27.0% based on 95% minimum convex polygons), with 66.7% of animals resident in the same burrow system using the same putative nest site. Collectively, examination of these data indicates that adult T. yonenagae share burrows and thus may be social. To place our findings in a comparative context and identify potential ecological correlates of burrow sharing in T. yonenagae we contrast our findings with data on space use by other fossorial, desert-dwelling rodents.

Capybaras, (Hydrochoerus hydrochaeris) are large, herbivorous New World hystricomorphs, common in the seasonally flooded savannas of tropical and subtropical South America. In this paper we review the social structure and dynamics of capybaras across much of their geographic range. Wherever they have been studied capybaras live in groups. Capybara groups are stable social units composed of adult males and females (sex ratio biased toward females) with their young. A linear dominance hierarchy characterizes interactions among males, and the dominant male obtains most matings. Group sizes range from 6 to 16 adult members and vary with habitat characteristics and population density. At higher densities group sizes and the proportion of floaters (apparently unaffiliated animals; mostly males) increase. In 1 low-density location dispersal appears to occur in groups of both sexes, whereas in another location, where density is higher, males disperse and females are philopatric. We also discuss more conceptual issues (mostly proximate and ultimate mechanisms) that relate to intraspecific variation in social behavior in general, and capybaras in particular.

Group living is thought to evolve whenever individuals attain a net fitness advantage due to reduced predation risk or enhanced foraging efficiency, but also when individuals are forced to remain in groups, which often occurs during high-density conditions due to limitations of critical resources for independent breeding. The influence of ecological limitations on sociality has been studied little in species in which reproduction is more evenly shared among group members. Previous studies in the caviomorph rodent Octodon degus (a New World hystricognath) revealed no evidence that group living confers an advantage and suggest that burrow limitations influence formation of social groups. Our objective was to examine the relevance of ecological limitations on sociality in these rodents. Our 4-year study revealed no association between degu density and use of burrow systems. The frequency with which burrow systems were used by degus was not related to the quality of these structures; only in 1 of the 4 years did the frequency of burrow use decrease with decreasing abundance of food. Neither the number of females per group nor total group size (related measures of degu sociality) changed with yearly density of degus. Although the number of males within social groups was lower in 2008, this variation was not related clearly to varying density. The percentage of females in social groups that bred was close to 99% and did not change across years of varying density. Our results suggest that sociality in degus is not the consequence of burrow limitations during breeding. Whether habitat limitations contribute to variation in vertebrate social systems is discussed.

Echimyid rodents are widely distributed and abundant throughout most of the Neotropics. I review the available information on spacing patterns and mating systems and develop a general framework for understanding variation among populations and species. In most studied species males have larger home ranges than do females, and overlap with either sex can range from 0% to nearly 100%. Males typically display more overlap with both other males and females than do females. Although lack of overlap has been interpreted as territoriality, most such cases have been from populations at low densities. Individuals of those same species show considerable overlap at higher densities. I suggest that individuals typically are not territorial but instead merely space themselves out when vacant space is abundant. Individuals are then facultatively monogamous because multiple mates are not available. As densities increase male home ranges overlap more simply because their home ranges are larger than those of females. Males then can acquire multiple mates, and polygyny becomes evident. At the highest densities multiple mates are available for both males and females, and promiscuity results. The mating system within a given population of many echimyids therefore depends upon density, which in turn is determined primarily by resource availability.

Cavies (family Caviidae) are a group of rodents distributed over much of South America. The high diversity of habitats inhabited by different species is paralleled by a high diversity of social organizations. Comparisons of behavioral and reproductive strategies between species can provide valuable insights into mammalian social evolution. In this review we 1st summarize the literature to give an idea of the diversity of social and mating systems within the genera Cavia, Galea, Microcavia, and Kerodon. Social systems range from solitary animals through pairs and harems to multimale–multifemale groups. Mating systems of cavies include monogamy and promiscuity and different forms of polygyny. We then review behavioral strategies of females and males that account for this social diversity. Particularly, the role of females and the potential of males to monopolize mates are examined. In some species, for example, estrous females actively solicit copulations with several males and thereby prevent their monopolization by single males. We also discuss adaptations of reproductive physiology to different mating systems. Finally, environmental factors influencing aspects of the social and mating systems of cavies are considered. Particularly, differences in resource distribution, predation risk, and climatic conditions might explain the great variation in species social organization.

Intraspecific variation in social systems is widely recognized across many taxa, and specific models, including polygamy potential, resource defense, and resource dispersion, have been developed to explain the relationship between ecological variation and social organization. Although mammals from temperate North America and Eurasia have provided many insights into this relationship, rodents from the Neotropics and temperate South America have largely been ignored. In this review we focus on reports documenting intraspecific variation in spacing systems, group size, and mating systems of caviomorphs. This large group of New World hystricognath rodents occupies a diverse array of habitats; thus, members of the same species potentially exhibit different social systems in response to different ecological conditions. Spatial patterns vary in response to a diverse array of factors, including predation, food availability, population density, and soil characteristics. Changes in group size typically correlate with changes in resource availability, particularly food. Mating systems generally reflect the ability of males to control access to females, which may depend on population density or food distribution. In general, social organization in caviomorphs fits predictions of resource-based models; however, most studies have been purely observational, involving small numbers of animals over short time periods and reporting qualitative rather than quantitative levels of ecological correlates. In future studies the use of molecular techniques and controlled, experimental manipulations can increase our understanding of intraspecific variation in caviomorph social systems. This understudied group of rodents offers excellent opportunities to provide insights into the influence of ecological conditions on behavior such as social systems.

In the late 1990s and early 2000s it was recognized that behavioral ecologists needed to study the sociality of caviomorph rodents (New World hystricognaths) before generalizations about rodent sociality could be made. Researchers identified specific problems facing individuals interested in caviomorph sociality, including a lack of information on the proximate mechanisms of sociality, role of social environment in development, and geographical or intraspecific variation in social systems. Since then researchers have described the social systems of many previously understudied species, including some with broad geographical ranges. Researchers have done a good job of determining the role of social environments in development and identifying the costs and benefits of social living. However, relatively little is known about the proximate mechanisms of social behavior and fitness consequences, limiting progress toward the development of integrative (evolutionary-mechanistic) models for sociality. To develop integrative models behavioral ecologists studying caviomorph rodents must generate information on the fitness consequences of different types of social organization, brain mechanisms, and endocrine substrates of sociality. We review our current understanding and future directions for research in these conceptual areas. A greater understanding of disease ecology, particularly in species carrying Old World parasites, is needed before we can identify potential links between social phenotypes, mechanism, and fitness.

Group size and vigilance are tools that animals can use to mitigate predation risk, and many studies have reported a negative relationship between them. Vigilance studies often investigate the direct effect of group size on vigilance, but they ignore the effect of ecological factors on group size. As a consequence, these studies can overlook important indirect effects of ecological factors on vigilance via group size. We investigated how ecological factors affect vigilance behavior in rock hyraxes (Procavia capensis), both directly and indirectly via group size. First, we showed a direct negative relationship between group size and vigilance behavior by measuring vigilance behavior before and after a change in group size. Second, we conducted a path analysis that included group size and several ecological factors (distance from shelter, distance from center of kopje, vegetation cover, and time since start of foraging session). Similar to the 1st analysis, the path analysis identified a strong negative relationship between group size and vigilance behavior; however, the other variables had little effect on group size or vigilance behavior, or both.

This study focuses on morphological and molecular data analyses, misidentifications, and phylogenetic inconsistencies regarding Bradypus variegatus (the brown-throated sloth) and B. tridactylus (the pale-throated sloth). Misidentifications were recorded on 75 of 313 museum specimens of Bradypus. Almost 90% of the misidentified specimens were B. variegatus from north-central Brazil, erroneously attributed to B. tridactylus. These misidentified specimens are reported in taxonomic reviews as the southernmost records of B. tridactylus. A history of confusing nomenclature regarding sloth species exists, and these particular misidentifications could be attributable to the similarity in face and throat color between B. variegatus from north-central Brazil and B. tridactylus. The molecular phylogeny of morphologically confirmed sloth specimens exhibits 2 monophyletic lineages representing B. variegatus and B. tridactylus. The split time between these 2 lineages was estimated at 6 million years ago (mya), contradicting previous studies that estimated this divergence to be 0.4 mya. Taxonomic inconsistencies were detected when comparing the molecular phylogeny to previously published DNA sequences ascribed to B. tridactylus. Misidentification or introgression could underlie such phylogenetic incongruities. Regardless of their causes, these discrepancies lead to misstatements regarding geographic distribution, phylogeny, and taxonomy of B. variegatus and B. tridactylus.

The only specialized ant-eating mammal in Australia and New Guinea is the egg-laying short-beaked echidna (Tachyglossus aculeatus), and this single species occurs throughout Australia in a wide range of habitats. Despite the diversity of habitats and density and distribution of prey species, home-range sizes throughout Australia seem remarkably similar. We radiotracked echidnas in a population in Tasmania over a 13-year period and calculated home-range sizes using the fixed kernel method and the minimum convex polygon method. No relationship was found between body mass and home-range size, and mean annual home-range size of males (90% kernels) was 107 ha ± 48 SD, twice that of females (48 ± 28 ha). Male home ranges overlapped considerably and also overlapped with those of several females. The echidna follows the pattern seen in many solitary eutherian mammals: both sexes are promiscuous, and males have larger home ranges than females. Echidnas show a high degree of home-range fidelity but can make rare excursions out of their normal area. Hibernating echidnas move between shelters during their periodic arousals, resulting in home-range sizes similar to those of the active period. Consistent with their very low metabolic rate, echidnas have home-range sizes considerably smaller than predicted for carnivorous or omnivorous mammals. Examination of data from other ant-eating mammals shows that as a group anteaters not only have smaller than predicted home ranges but they depart significantly from the normal relationship between home-range size and body mass.

A new species of Tapirus (Perissodactyla: Tapiridae) is described from the upper Pleistocene of the Rio Madeira Formation in Araras, Nova Mamoré Municipality, Rondonia State, Brazil. Tapirus rondoniensis sp. nov. is represented by a nearly complete skull with a unique combination of characters that differ from those of extant and fossil species of Tapirus described from South America. It is diagnosed mainly by its broad frontals that bear a pneumatization extending to the frontoparietal suture, a high sagittal crest, a weakly molarized P2 lacking a protoloph, and a metaloph that merely reaches the base of the ectoloph. T. rondoniensis sp. nov. is similar in some respects to T. terrestris, but it retains some primitive dental and cranial character states in common with T. pinchaque, such as broad frontals and a weakly molarized P2.

Monodelphis (short-tailed opossums) is the most speciose South American marsupial genus, wtih species distributed from Panama to Argentina. The goal of the present study was to analyze levels and patterns of genetic variation in M. brevicaudata (Guianan short-tailed opossum), M. dimidiata (yellow-sided opossum), M. domestica (gray short-tailed opossum), and M. kunsi (pygmy short-tailed opossum) using sequences of the mitochondrial cytochrome b (Cytb) and nuclear interphotoreceptor retinoid-binding protein (IRBP) genes from individuals sampled in the Amazon, Cerrado, Caatinga, Atlantic Forest, and Pampa biomes in Brazil. Species relationships also were analyzed using sequences of 9 other Monodelphis species retrieved from GenBank and representing 3 localities in Brazil and 17 sites in other South American countries. M. domestica and M. brevicaudata showed phylogeographic structure, but M. dimidiata and M. kunsi did not. Maximum parsimony, maximum likelihood, and Bayesian algorithms showed similar topologies for estimated phylogenetic trees. Analyses of individual genes produced comparable results, but combined loci produced trees with higher support. All Monodelphis haplotypes were monophyletic, with M. emiliae (Emilia's short-tailed opossum) sister to all other species, which form 2 groups. M. brevicaudata (from the Amazon) forms a well-supported clade with M. domestica (which occupies several biomes) and 2 unidentified Amazonian species. The other branch has M. kunsi (from the Cerrado) as sister to a well-supported clade of 5 Amazonian species.

Temporal partitioning in foraging patterns of syntopic Virginia opossums (Didelphis virginiana) and raccoons (Procyon lotor) was investigated at 3 sites in western Tennessee through the use of timers attached to live traps on trapping grids and through time-stamped remote photography using infrared-triggered cameras at bait stations. Data were analyzed using Watson's U²-test, chi-square analyses, and probability tests. Results revealed no intraspecific differences in time of foraging for either species and a lack of interspecific differentiation. A high degree of overlap in foraging times of the species was observed. Virginia opossums and raccoons apparently did not partition their times of foraging. Foraging patterns of each species seem to be independent of the other (neutral association).

The Andean cat (Leopardus jacobita) is one of the most endangered, yet least known, felids. Although the Andean cat is considered at risk of extinction, rigorous quantitative population studies are lacking. Because physical observations of the Andean cat are difficult to make in the wild, we used a camera-trapping array to photo-capture individuals. The survey was conducted in northwestern Argentina at an elevation of approximately 4,200 m during October–December 2006 and April–June 2007. In each year we deployed 22 pairs of camera traps, which were strategically placed. To estimate detection probability and density we applied models for spatial capture–recapture using a Bayesian framework. Estimated densities were 0.07 and 0.12 individual/km² for 2006 and 2007, respectively. Mean baseline detection probability was estimated at 0.07. By comparison, densities of the Pampas cat (Leopardus colocolo), another poorly known felid that shares its habitat with the Andean cat, were estimated at 0.74–0.79 individual/km² in the same study area for 2006 and 2007, and its detection probability was estimated at 0.02. Despite having greater detectability, the Andean cat is rarer in the study region than the Pampas cat. Properly accounting for the detection probability is important in making reliable estimates of density, a key parameter in conservation and management decisions for any species.

The island spotted skunk (Spilogale gracilis amphiala) is endemic to the 2 largest California Channel Islands, Santa Cruz and Santa Rosa. Unlike the island fox (Urocyon littoralis) and island subspecies of the deer mouse (Peromyscus maniculatus), the island spotted skunk shows no morphological differentiation between islands and is differentiated only weakly from mainland subspecies, suggesting recent colonization. However, the islands have been isolated from each other and the mainland throughout the Quaternary Period. We used 8 microsatellite loci to investigate the distribution of genetic variation within and among populations of spotted skunks from 8 localities (the 2 islands and 6 mainland localities), representing 4 subspecies. Tissue samples were obtained from 66 fresh specimens collected from 2000 to 2002 and 142 museum specimens collected from 1906 to 1994. Allelic richness and heterozygosity in island spotted skunk populations was approximately 30% lower than that found in mainland localities or subspecies. All localities or subspecies were significantly differentiated (mean F_ST was 0.17 and 0.13 for localities and subspecies, respectively). Contrary to comparisons based on morphological data, genetic differentiation was especially strong between islands and between island and mainland localities or subspecies. Patterns of differentiation suggest that skunks colonized the Channel Islands shortly before rising sea levels separated Santa Cruz and Santa Rosa islands (11,500 years ago). Our results indicate that the taxonomic status of the island spotted skunk should be reconsidered and that both island populations might constitute evolutionarily significant units worthy of conservation.

We studied the effect of ecological light pollution on a rocky desert community, focusing on 2 spiny mouse congeners, nocturnal Acomys cahirinus (common spiny mouse) and diurnal Acomys russatus (golden spiny mouse). We hypothesized that in response to artificial illumination A. cahirinus will decrease its activity and A. russatus will increase its activity, and thus temporal overlap and interspecific competition could increase. Our study took place in 4 field enclosures: the 1st and 3rd months were controls with natural light, and in the 2nd month artificial illumination, simulating low levels of light pollution, was set for the first 3 h of the night. We implanted temperature-sensitive radiotransmitters to monitor mouse activity, and individual identification tags with automonitored foraging patches were used to track foraging behavior. A. cahirinus decreased activity and foraging with artificial lighting, restricting movement particularly in less-sheltered microhabitats, probably because of increased predation risk. Because illumination restricted both activity time and space, intraspecific encounters of A. cahirinus over foraging patches increased during and following the illuminated hours. However, diurnal A. russatus did not expand its activity into the illuminated hours, possibly due to the presence of competing A. cahirinus, or to nonfavorable environmental conditions. Therefore, overt interspecific competition was not affected by experimental light pollution. Light pollution had a negative influence by reducing overall activity and producing a relatively underexploited temporal niche, which may promote invasion of alien species that are less light sensitive; and by increasing intraspecific overlap in foraging A. cahirinus.

In this contribution we describe the fossil remains of a new genus and species of a giant rodent, Arazamys castiglionii (Mammalia, Rodentia, Dinomyidae), from Arazatí beach in San José Department, southern Uruguay. The specimen was exhumed from pelitic sediments of the Camacho Formation, biostratigraphically assigned to the late Miocene Huayquerian South American Land Mammal Age. The remains include an incomplete skull (braincase, auditory region, and nearly full dentition) and the atlas. Based on comparative studies of the anatomy of the auditory region, we describe 2 morphologies for the subfamily Eumegamyinae, 1 characterized by a short meatus acusticus externus, a great development of the foramen stylomastoideum, and a conspicuous ectotympanic cavity, and a 2nd characterized by a long meatus acusticus externus and lack of the ectotympanic fossa. The potential taxonomic and systematic value of the auditory region in Dinomyidae is discussed.

In winter southern flying squirrels (Glaucomys volans) aggregate in large groups. They live on food items individually stored during the fall in their overlapping home ranges. The squirrels gain thermoregulatory benefits from living in aggregations but also face costs of group living, especially nest mates pilfering individually stored food. Other costs include increased predator attraction and a greater vulnerability to parasite infection. The presence of relatives in the group has the potential to increase inclusive fitness by increasing the availability of food, stored in the home area, to related individuals. Using 3 generations of known-relationship squirrels we conducted laboratory experiments to determine whether kin or familiar animals were preferred nest mates during aggregation formation. During 3 time periods, over 2 winters, squirrels were presented with kin and nonkin and familiar and unfamiliar animals and allowed to aggregate over the course of multiple 3-day trials. Kinship was persistently a major factor in the formation of aggregations. Squirrels aggregated with highly related animals (parents, offspring, and siblings) significantly more often than with unrelated animals. Familiarity became significant by the end of the study. Understanding how relatedness and familiarity interact in the formation of aggregations in seasonally gregarious animals sheds light on the processes and factors that lead to sociality.

Movements away from the natal or home territory are important to many ecological processes, including gene flow, population regulation, and disease epidemiology, yet quantitative data on these behaviors are lacking. Red foxes exhibit 2 periods of extraterritorial movements: when an individual disperses and when males search neighboring territories for extrapair copulations during the breeding season. Using radiotracking data collected at 5-min interfix intervals, we compared movement parameters, including distance moved, speed of movement, and turning angles, of dispersal and reproductive movements to those made during normal territorial movements; the instantaneous separation distances of dispersing and extraterritorial movements to the movements of resident adults; and the frequency of locations of 95%, 60%, and 30% harmonic mean isopleths of adult fox home territories to randomly generated fox movements. Foxes making reproductive movements traveled farther than when undertaking other types of movement, and dispersal movements were straighter. Reproductive and dispersal movements were faster than territorial movements and also differed in intensity of search and thoroughness. Foxes making dispersal movements avoided direct contact with territorial adults and moved through peripheral areas of territories. The converse was true for reproductive movements. Although similar in some basic characteristics, dispersal and reproductive movements are fundamentally different both behaviorally and spatially and are likely to have different ultimate purposes and contrasting effects on spatial processes such as disease transmission.

A recent morphometric model that estimates endocranial volume from 3 linear dimensions taken on the outside of the braincase has increased dramatically both the number and the taxonomic breadth of fossil and extant members of the Carnivora with endocranial volume estimates. I present a similar model for the Artiodactyla, relating volume of the endocranial cavity to braincase height, width, and length. Using Akaike information criterion–based modeling methods, I derived a set of predictive equations with respect to a recent supermatrix phylogeny of the Artiodactyla. Three distinct allometric equations are reconstructed: for Bovidae, nonbovid ruminants, and nonruminant artiodactyls. This model accurately predicted endocranial volumes for artiodactyls (R²  =  0.942), and can be used to expand the available sample of fossil and extant taxa for which endocranial volume estimates exist. This will permit reconstruction of the plesiomorphic scaling of brain volume relative to body mass and testing of hypotheses of the evolution in brain size within the artiodactyl clade and coevolutionary arms races between carnivore and ungulate communities.

Timing (mean birth date) and synchrony (variance around that date) of births can influence survival of young and population growth in ungulates. We quantified timing and synchrony of births in 2 populations of bighorn sheep (Ovis canadensis) that were acquired from different source herds and reintroduced to adjacent areas. From 2001 to 2007 we recorded 121 birth dates to test whether timing and synchrony of parturition were similar between populations. Furthermore, we calculated population-wide survival of young to their 1st winter. Females on Mount Timpanogos gave birth later than females inhabiting Rock Canyon from 2001 to 2002 and in 2004; those females gave birth earlier in 2007 than females inhabiting Rock Canyon. Timing of births was similar in 2003 and from 2005 to 2006. The relationship between differences in mean birth dates between populations and time since reintroduction was marginally nonsignificant (P  =  0.075), whereas differences in synchrony of births were negatively related to time since reintroduction (P  =  0.005). Survivorship of young was higher for females in Rock Canyon that gave birth on average 30 days earlier from 2001 to 2002 and during 2004 than for females on Mount Timpanogos during those years. Our findings provide evidence that within 5 years after reintroduction bighorn sheep adjusted timing and synchrony of parturition to environmental conditions of their release site. A slow adjustment of these life-history characteristics by females on Mount Timpanogos possibly contributed to lower survival of young to their 1st winter during 2001–2002 and 2004, which could have impeded establishment of those mammals in that study area.

One demand to which organisms must allocate energy for maintenance, growth, and reproduction is the immune system. Because the immune system is energetically costly, spleen size is expected to be condition-dependent. Parasites also can influence spleen size. Parasites draw resources from their host, with consequences for host body condition. Male American mink (Neovison vison) were examined for parasite prevalence, intensity, and richness to test several predictions: individuals in good condition have large spleens; heavily parasitized individuals have large spleens; and heavily parasitized individuals are in poorer condition than individuals with few parasites. Spleen mass was related positively to both body condition and parasite richness, but spleen mass was not associated with prevalence or intensity of individual parasites. Body condition was related weakly to the intensity of parasitism by the giant kidney worm and sinus worm, but otherwise parasite prevalence, intensity, or richness were not associated with body condition. These results are similar to those found in studies of birds, suggesting that comparable processes occur in mammals.

Human suppression of fire has resulted in altered species composition and dense forest stands across the western United States. Accumulation of understory shrubs makes forests vulnerable to catastrophic fire and can impact animal use, whereas fire prescription can ameliorate negative impacts of suppression. We used radiotelemetry to determine patterns of habitat use and survival of Mexican fox squirrels (Sciurus nayaritensis chiricahuae) in fire-suppressed and fire-prescribed areas of the Chiricahua Mountains, Arizona. Core areas of squirrels within fire-suppressed areas were larger and contained more understory shrubs than core areas of squirrels in fire-prescribed areas. Shrub cover and canopy heterogeneity influenced core-area size and distance traveled, and squirrels that were depredated traveled farther than conspecifics that survived, but shrub cover and canopy heterogeneity were not directly associated with squirrel survival. Suppression-induced increases in understory vegetation might force squirrels to travel greater distances to meet energetic requirements and thereby increase predation risk. Retention of mature forested canyons and restoration of natural fire regimes will be important for the persistence of Mexican fox squirrels.

Guidelines for use of wild mammal species are updated from the American Society of Mammalogists (ASM) 2007 publication. These revised guidelines cover current professional techniques and regulations involving mammals used in research and teaching. They incorporate additional resources, summaries of procedures, and reporting requirements not contained in earlier publications. Included are details on marking, housing, trapping, and collecting mammals. It is recommended that institutional animal care and use committees (IACUCs), regulatory agencies, and investigators use these guidelines as a resource for protocols involving wild mammals. These guidelines were prepared and approved by the ASM, working with experienced professional veterinarians and IACUCs, whose collective expertise provides a broad and comprehensive understanding of the biology of nondomesticated mammals in their natural environments. The most current version of these guidelines and any subsequent modifications are available at the ASM Animal Care and Use Committee page of the ASM Web site ( http://mammalsociety.org/committees/index.asp).