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Supplemental food from anthropogenic sources is a source of conflict with humans for many wildlife species. Food-seeking behaviours by black bears Ursus americanus and brown bears Ursus arctos can lead to property damage, human injury and mortality of the offending bears. Such conflicts are a well-known conservation management issue wherever people live in bear habitats. In contrast, the use of anthropogenic foods by the polar bear Ursus maritimus is less common historically but is a growing conservation and management issue across the Arctic. Here we present six case studies that illustrate how negative food-related interactions between humans and polar bears can become either chronic or ephemeral and unpredictable. Our examination suggests that attractants are an increasing problem, exacerbated by climate change-driven sea-ice losses that cause increased use of terrestrial habitats by bears. Growing human populations and increased human visitation increase the likelihood of human–polar bear conflict. Efforts to reduce food conditioning in polar bears include attractant management, proactive planning and adequate resources for northern communities to reduce conflicts and improve human safety. Permanent removal of unsecured sources of nutrition, to reduce food conditioning, should begin immediately at the local level as this will help to reduce polar bear mortality.

Sloth bears behave aggressively toward humans when threatened and are among the most dangerous wildlife in India. Safety messaging for those who live in sloth bear country must be accurate to be effective, and messaging may need to be modified to account for regional differences in human-bear relationships. The timing of sloth bear attacks on the Deccan Plateau of Karnataka, both by season and by time of day, deviated enough from those reported in other areas such that it warranted further investigation. We compared data from eight studies of human-sloth bear conflict from across the Indian subcontinent and explored possibilities as to why differences exist. Seasonally all studies reported that human-sloth bear conflict was highest when human activity in the forest was greatest, though the season of highest human activity varied significantly by region (χ2 = 5921, df = 5, P χ2 = 666, df = 5, P

Polar bears are the largest bear species and a top marine predator in the Arctic. They share many reproductive characteristics with other bears but have significant adaptations that enable them to reproduce and thrive in the Arctic. Sexual dimorphism and the ever-changing sea ice habitat influence polar bear reproductive behavior. Without static home ranges, male polar bears search widely for estrous females, often using olfactory cues. The mating system is polygynous, with males competing for mating opportunities in the spring. Delayed implantation allows females to acquire adequate fat reserves for fetal development and lactation prior to denning. Denning is facultative except in pregnant females, which may remain in dens for up to seven months. During the winter, they give birth and nurse altricial cubs, then emerge from the den in the spring. Cubs are weaned at 2.3 years of age. The prolonged pre-weaning period and a cub mortality rate of 20–96% result in a low reproductive rate compared with other terrestrial mammals. If the sea ice continues its current trajectory of decline because of climate change, up to two-thirds of existing polar bear populations may disappear by the middle of the twenty-first century

Timing of births in ungulates is influenced by ecological factors, and differences in seasonality of births have evolutionary implications for these mammals. Birthing habitat is one of the most important home-range attributes for ungulates, and disturbances during this time can decrease survival of young and population growth. We calculated timing of births and quantified habitat selected by nursery groups (i.e., females with young) of desert bighorn sheep (Ovis canadensis nelsoni) to produce and project a geographic information system (GIS) model of lambing period habitat (i.e., birthing locations and areas used up to 6 weeks post-parturition) in southeastern Utah, United States. We then applied that model to identify suitable lambing period habitat in an adjacent area for a population of Rocky Mountain bighorn sheep (O. c. canadensis). We monitored 19 global positioning system (GPS) collared females from 2012 to 2013 to delineate the birthing season. We used GPS locations during that time and logistic regression within a model-selection framework to differentiate between lambing period habitat and random locations based on habitat and anthropogenic covariates. We used model coefficients to produce and project a GIS model of lambing period habitat. Across both years, 89% of 45 births occurred in May (range = April 27–June 9). We quantified covariate values at 750 lambing period and 750 random locations during that time in the San Rafael study area. The top model included elevation, slope, terrain ruggedness, aspect, existing vegetation type, and distance to trails and roads. Those variables predicted lambing period habitat for desert bighorn sheep (rho = 0.99, P = 0.02). We then overlaid that model on 1,130 GPS locations from 17 female Rocky Mountain bighorns in the Green River study area. In both areas, a mean of 71% of locations were in the top two (of five) probability categories (San Rafael high = 37%, medium high = 31%; Green River high = 50%, medium high = 23%). Females in lambing period habitat preferred steep, north-facing slopes, rugged terrain, low elevation, and avoided roads. Our GIS model projected areas of lambing period habitat for adjacent desert and Rocky Mountain bighorns and provided land managers with a map of habitat in areas where resource extraction and recreation are increasing. Identifying timing of parturition, and high-probability lambing period habitat, will help managers mitigate temporal and spatial conflicts between bighorn sheep and anthropogenic activities. Similar data regarding timing of births and a GIS model can be applied to conserve habitat for other ungulates also.

Denned polar bears are invisible under the snow, therefore winter-time petroleum exploration and development activities in northern Alaska have potential to disturb maternal polar bears and their cubs. Previous research determined forward looking infrared (FLIR) imagery could detect many polar bear maternal dens under the snow, but also identified limitations of FLIR imagery. We evaluated the efficacy of FLIR-surveys conducted by oil-field operators from 2004-2016. Aerial FLIR surveys detected 15 of 33 (45%) and missed 18 (55%) of the dens known to be within surveyed areas. While greater adherence to previously recommended protocols may improve FLIR detection rates, the physical characteristics of polar bear maternal dens, increasing frequencies of weather unsuitable for FLIR detections—caused by global warming, and competing “hot spots” are likely to prevent FLIR surveys from detecting maternal dens reliably enough to afford protections consonant with increasing global threats to polar bear welfare.

Monitoring dispersal, habitat use, and social mixing of released ungulates is crucial for successful translocation and species conservation. We monitored 127 female bighorn sheep (Ovis canadensis) released in three populations from 2000 to 2009 to investigate if augmented bighorns expanded and shifted seasonal ranges, used different habitat compared with resident females, and if animals mixed socially. Augmented bighorns in all populations expanded range use compared with residents by shifting utilization distributions. Size of utilization distributions, however, were smaller for augmented females compared with residents in all areas except one. Overlap of seasonal utilization distributions between augmented and resident bighorns and use of slope and elevation differed across populations. In two populations, differences in size and overlap of seasonal utilization distributions and use of slope and elevation supported the hypothesis that habitat use of bighorns in their source area influenced their habitat use after release. Mixing between resident and augmented adult females occurred on average during only 21% of sightings and was similar across populations. Our results clarify how augmented bighorns mix with resident animals and how habitat use is modified following augmentations. Such information is needed to improve bighorn sheep augmentations and can be applied to augmentations of other ungulates.

Synchrony between reproduction and food availability is important in mammals due to the high energetic costs of gestation and lactation. Female polar bears (Ursus maritimus) must accumulate sufficient energy reserves during spring through autumn to produce and nurse cubs during the winter months in snow dens. Adequate time in a den is important to optimize cub development for withstanding harsh Arctic spring conditions and to synchronize emergence with peak prey availability, which occurs in May and June. During 1985–2013, den phenology was investigated using temperature data collected on satellite collars deployed on adult female polar bears in the southern Beaufort Sea (SB) and Chukchi Sea (CS). We examined relationships between den phenology, reproductive success (cub production and post-emergence survival), and environmental factors (weather and sea-ice conditions). Females observed with cubs emerged later and remained in dens on average 15.0 ± 7.6 (SE) days longer than females seen without cubs. Females occupying land-based dens, where estimated snowfall was greater, had higher reproductive success. Recently, female polar bears have increased land-based denning in the SB. Females in CS emerged later from dens than SB females, consistent with better female body condition and higher cub survival in the CS. During years with a greater area of autumn sea ice, reproductive success was higher at land-based versus sea-ice dens, suggesting continued decline in sea ice could negatively affect recruitment. However, further research is needed to better understand mechanistic relationships. Because females emerging later from dens had higher reproductive success, den duration could be a useful metric in population monitoring.

Feral horses ( Equus callabus ) occur throughout the world on all continents except Antarctica. In North America, feral horses occupy 31.6 million acres throughout western North America. Throughout their range, feral horses often share habitat with American pronghorn ( Antilocapra americana) . Since horses are larger and more aggressive than pronghorn, they are considered socially dominant. In the Great Basin of western North America, pronghorn often access water sources where horses occur since habitat preferences are similar. If pronghorn are excluded where water is used by both species, pronghorn fitness may be impaired, especially during dry or droughty periods. The purpose of this study was to investigate interference competition between pronghorn and feral horses at water sources within the Great Basin. We observed horses and pronghorn at high-use water sources and recorded all occurrences and outcomes of pronghorn/horse interactions. We assessed differences in pronghorn behavior in the presence or absence of horses. Pronghorn invested more time on vigilance behavior and less time foraging or drinking in the presence of horses than in their absence. Nearly half of pronghorn/horse interactions resulted in pronghorn exclusion from water. We conclude that as feral horse numbers increase, competition for water will subsequently increase.

The sloth bear (Melursus ursinus) is endemic to India, Nepal, Bhutan, and Sri Lanka, and is among the least studied of all bear species. Sloth bears behave aggressively toward humans when they feel threatened and are considered among the most dangerous wild animals in India. Our research objective was to interview those that had close encounters with sloth bears and attack survivors so that we could learn from these unfortunate events and prepare persons to be safe in sloth bear country. Consequently, we interviewed 342 people—162 that had close encounters that did not result in attacks and 180 that were involved in attacks—in the southern Indian state of Karnataka between the years 1985 and 2016. Our surveys revealed that all attacks were defensive in nature, that people that had been making noise while moving through sloth bear country were less likely to be attacked, and that persons in groups of ≥2 were very rarely attacked. Nine percent of people that fought back during an attack were killed and 11% of people that attempted to run from the bear were killed. There were no deaths among people that fell to the ground and did not fight back. Drawing from this work and that of others, we provide suggestions for safe conduct in sloth bear country.

ContextHuman activity in wildlands can influence wildlife populations by decreasing or degrading habitat, decreasing survival, or through displacement. For bighorn sheep (Ovis canadensis), some human activities are detrimental and may result in physiological stress, altered activity budgets, or habitat abandonment. From 1979 to 2000, human recreation increased over 300% in areas occupied by desert bighorn sheep (O. c. nelsoni) in south-eastern Utah. Concurrently, the population of desert bighorn sheep occupying the Potash Bighorn Sheep Management Unit of south-eastern Utah was in steep decline. AimsWe investigated behavioural responses of desert bighorn sheep to different levels of human activity in this area from 2002 to 2003. MethodsWe divided the study population into two areas on the basis of the level of human use, i.e. low and high. We observed desert bighorn sheep at seven sites within these areas, including three with a high level of human use and four areas of a low level of human use. Key resultsDesert bighorn sheep spent significantly less time grazing and more time vigilant in areas of a high level of human use than in areas of a low level of human use. ConclusionsHuman recreational use of desert bighorn sheep habitat has the potential to negatively affect foraging by desert bighorn sheep. ImplicationsWe raise a cautionary flag because recreational use in bighorn sheep habitat near Moab, Utah, continues to increase and bighorn numbers continue to decline. When managers consider proposals to increase areas or trails for human recreation, they should incorporate ways to minimise impacts and reduce stressors to bighorn sheep.

Bighorn sheep (Ovis canadensis) often die from respiratory disease after commingling with domestic sheep. From 2000 to 2009, we observed commingling between domestic and reintroduced bighorn sheep in 3 populations in UT, USA. We investigated how commingling affected survival of radio-collared female bighorns that were released initially (founder) and those that were subsequently released (augmented). We predicted that the proportion of young surviving to their first winter and population growth would be lower after observed commingling with domestic sheep. We observed groups of bighorns year-round on 2,712 occasions and commingling between domestic sheep and bighorns in 6 instances. On Mount Timpanogos, survival rates were best modeled as constant for females (n = 57) before and after observed commingling with domestic sheep. Survival rates of female bighorns, however, decreased significantly in Rock Canyon (n = 21) and on Mount Nebo (n = 22) for founder, but not augmented bighorns after observed commingling with domestic sheep. Also, the proportion of young surviving to their first winter was almost 3 times lower and population growth was reduced for bighorns after observed commingling with domestic sheep in Rock Canyon and on Mount Nebo. Commingling between domestic and bighorn sheep reduced population parameters in 2 of 3 bighorn populations we studied; however, on Mount Timpanogos, interactions between those 2 species were not fatal for radio-collared female bighorns. Wildlife biologists should manage for spatial separation of these 2 species and consider the location of hobby farms and trailing operations of domestic sheep near release sites for bighorns.

Female polar bears construct maternal dens in snowdrifts in autumn. Forward-looking infrared (FLIR) has been used to locate dens to prevent disruption of denning by human activities, but the results have been mixed. To identify limitations and optimal conditions for locating dens, we took handheld FLIR images of three artificial dens under varied conditions. We tested variables hypothesized to influence detectability with linear models using the zero-inflated negative binomial distribution. Solar radiation, wind speed, and den wall thickness reduced the likelihood of detecting dens. The negative effect of wind speed on detectability increased with increasing distance. To maximize the efficacy of ground-based FLIR, den surveys should be conducted when solar radiation is less than 16 watts per square meter (night) and when wind speed is less than 10 kilometers per hour. Adherence to these guidelines will maximize the protection that FLIR can afford to denning bears.

We measured American black bear (Ursus americanus) responses to hikers, small power skiffs, kayakers, and overnight campsites within coastal salt marsh foraging areas. To accomplish this, we experimentally approached bears in the intertidal and supratidal zones of Aialik Bay (AB) and Nuka Bay (NB), Kenai Fjords National Park, Alaska. We chose these areas due to their different levels of human activity (AB = high, NB = low). In the first experiments, we determined the overt response distances (ORD: when bears first responded to our approaches) and flight initiation distances (FID: the distance at which bears were pushed from their original location) for 118 black bear groups involving 136 bears. We found no difference between ORD response to power skiffs and versus kayaks, nor between those responding to kayaks versus foot approaches. However, bears first responded to power skiffs 50 m farther than first responses to foot approaches. There was no difference in FID between all modes of approach...

Conflict between black bears (Ursus americanus) and humans has occurred in Utah, but the records are largely incomplete. To document these events, the Utah Division of Wildlife Resources initiated a black bear sightings and encounters database in 2003, and we updated it. From 2003–2013, there were 224 recorded events, with 10 attacks, 208 property damages, and 6 vehicle collisions. Most events took place at campsites (40%). The most common season for events was summer (78%). Most conflict occurred at night. The number of events has not increased over the last 10 years, with no significant relationship between the number of events per year and drought. Most events involved single bears, and over half of events occurred when food or garbage was available for the bear.

We compiled, summarized, and reviewed 269 incidents of bear-human conflict involving firearms that occurred in Alaska during 1883-2009. Encounters involving brown bears (Ursus arctos; 218 incidents, 81%), black bears (Ursus americanus; 30 incidents, 11%), polar bears (Ursus maritimus; 6 incidents, 2%), and 15 (6%) unidentified species provided insight into firearms success and failure. A total of 444 people and at least 367 bears were involved in these incidents. We found no significant difference in success rates (i.e., success being when the bear was stopped in its aggressive behavior) associated with long guns (76%) and handguns (84%). Moreover, firearm bearers suffered the same injury rates in close encounters with bears whether they used their firearms or not. Bears were killed in 61% (n = 162) of bear-firearms incidents. Additionally, we identified multiple reasons for firearms failing to stop an aggressive bear. Using logistic regression, the best model for predicting a successful outcome for firearm users included species and cohort of bear, human activity at time of encounter, whether or not the bear charged, and if fish or game meat was present. Firearm variables (e. g., type of gun, number of shots) were not useful in predicting outcomes in bear-firearms incidents. Although firearms have failed to protect some users, they are the only deterrent that can lethally stop an aggressive bear. Where firearms have failed to protect people, we identified contributing causes. Our findings suggest that only those proficient in firearms use should rely on them for protection in bear country. (C) 2012 The Wildlife Society. Language: en

In March 2009, we documented the death of one member of a triplet polar bear (Ursus maritimus) litter at its den site in the southern Beaufort Sea (SBS) of Alaska. We used a self-contained video camera unit to document activity between den emergence and departure. All three cubs showed low activity levels relative to other cubs observed, and one died within one week of den emergence. Necropsy confirmed that the dead cub had a low body weight and was malnourished. Capture later confirmed that the two surviving cubs were also undersized. Polar bear cub survival is influenced by many factors including litter size and sea ice conditions. Triplet litters are often smaller and suffer higher mortality rates than singletons and twins. This cub was not only a triplet but also born following 2 years of record minimum sea ice extent, both of which may have played a role in this cub’s demise.

At least 63 people were killed in 59 incidents by non-captive black bear (Ursus americanus) during 1900–2009. Fatal black bear attacks occurred in Canada and Alaska (n = 49) and in the lower 48 states (n = 14). There were 3.5 times as many fatal attacks in Canada and Alaska but only 1.75 times as many black bears, and much less human contact for black bears in Canada and Alaska. There was a weak positive correlation (rs = 0.56, P ≤ 0.000) between the estimated size of a bear population within a given jurisdiction and the number of fatal black bear attacks. Some jurisdictions had no fatal black bear attacks but had large estimated black bear populations. Of fatal attacks, 86% (54 of 63, 1.08/yr) occurred between 1960 and 2009. There was positive linear relationship between the number of fatal black bear attacks per decade and human population size in the United States and Canada per decade (r2 = 0.92, β = 0.000, P ≤ 0.001). Of fatal attacks, 91% (49 of 54) occurred on parties of 1 or 2 persons. In...

We present a comprehensive look at a sample of bear spray incidents that occurred in Alaska, USA, from 1985 to 2006. We analyzed 83 bear spray incidents involving brown bears (Ursus arctos; 61 cases, 74%), black bears (Ursus americanus; 20 cases, 24%), and polar bears (Ursus maritimus; 2 cases, 2%). Of the 72 cases where persons sprayed bears to defend themselves, 50 (69%) involved brown bears, 20 (28%) black bears, and 2 (3%) polar bears. Red pepper spray stopped bears' undesirable behavior 92% of the time when used on brown bears, 90% for black bears, and 100% for polar bears. Of all persons carrying sprays, 98% were uninjured by bears in close-range encounters. All bear-inflicted injuries (n = 3) associated with defensive spraying involved brown bears and were relatively minor (i.e., no hospitalization required). In 7% (5 of 71) of bear spray incidents, wind was reported to have interfered with spray accuracy, although it reached the bear in all cases. In 14% (10 of 71) of bear spray incidents...

We present a database application designed to standardize the collection and entry of brown and black bear (Ursus arctos and U. americanus)-human interaction data, formalize data storage methods, and analyze patterns of bear-human interactions in Alaska's National Parks. The National Park Service Alaska Region Bear-Human Information Management System (BHIMS) facilitates the systematic collection of biologically relevant data, consolidates bear management information, helps identify management priorities, facilitates the development of science-based bear management plans, helps evaluate the effectiveness of management strategies, helps provide more effective bear safety messages, creates permanent digital copies of original data, establishes bear management institutional memory, and ultimately improves bear conservation and human safety. The BHIMS can be modified for use in other locales and has applicability to bear management across North America.

Intraspecific killing has been reported among polar bears (Ursus maritimus), brown bears (U. arctos), and black bears (U. americanus). Although cannibalism is one motivation for such killings, the ecological factors mediating such events are poorly understood. Between 24 January and 10 April 2004, we confirmed three instances of intraspecific predation and cannibalism in the Beaufort Sea. One of these, the first of this type ever reported for polar bears, was a parturient female killed at her maternal den. The predating bear was hunting in a known maternal denning area and apparently discovered the den by scent. A second predation event involved an adult female and cub recently emerged from their den, and the third involved a yearling male. During 24 years of research on polar bears in the southern Beaufort Sea region of northern Alaska and 34 years in northwestern Canada, we have not seen other incidents of polar bears stalking, killing, and eating other polar bears. We hypothesize that nutritional stresses related to the longer ice-free seasons that have occurred in the Beaufort Sea in recent years may have led to the cannibalism incidents we observed in 2004.

Recently, brown bear (Ursus arctos) viewing has increased in coastal Alaska and British Columbia, as well as in interior areas such as Yellowstone National Park. Viewing is most often being done under conditions that offer acceptable safety to both people and bears. We analyze and comment on the underlying processes that lead brown bears to tolerate people at close range. Although habituation is an important process influencing the dis- tance at which bears tolerate people, other variables also modify levels of bear-to-human tolerance. Because bears may react internally with energetic costs before showing an overt reaction to humans, we propose a new term, the Overt Reaction Distance, to emphasize that what we observe is the external reaction of a bear. In this paper we con- ceptually analyze bear viewing in terms of benefits and risks to people and bears. We conclude that managers and policy-makers must develop site-specific plans that identify the extent to which bear-to-human habituation and tolerance will be permitted. The pro- posed management needs scientific underpinning. It is our belief that bear viewing, where appropriate, may promote conservation of bear populations, habitats, and ecosys- tems as it instills respect and concern in those who participate.

We present a new paradigm for understanding habituation and the role it plays in brown bear (Ursus arctos) populations and interactions with humans in Alaska. We assert that 3 forms of habituation occur in Alaska: bear-to-bear, bear-to-human, and human-to-bear. We present data that supports our theory that bear density is an important factor influencing a bear's overt reaction distance (ORD); that as bear density increases, overt reaction distance decreases, as does the likelihood of bear–human interactions. We maintain that the effects of bear-to-bear habituation are largely responsible for not only shaping bear aggregations but also for creating the relatively safe environment for bear viewing experienced at areas where there are high densities of brown bears. By promoting a better understanding of the forces that shape bear social interactions within populations and with humans that mingle with them, we can better manage human activities and minimize bear–human conflict.

Summary As a result of the move towards regional techniques, today's anaesthetic trainee has limited exposure to general anaesthesia for caesarean section. This is compounded by recent changes in working practice that restrict training hours. The latter also diminishes the trainee's exposure to common and to more rare obstetric emergencies. Management of obstetric emergencies requires not only technical skills but also good team working skills and this is rarely taught in traditional training programmes. In addition, the ethics of practicing regional techniques on patients when alternative learning tools are available are questionable. In this article we discuss the challenges facing trainers and trainees in obstetric anaesthesia. We propose a need for changes in training programmes to embed the use of simulation for training in both technical and human factors skills. The uses of epidural simulators, airway trainers, whole body patient simulators and emergency drill training in both the workplace and in specialized simulation centres are discussed. A potential role for simulation in assessment of trainees is also considered.

The increasing popularity of brown bear (Ursus arctos) viewing at Brooks River in Katmai National Park, Alaska has resulted in overcrowded facilities, increasing bear-human conflicts, displacement of bears from important habitats, and degradation of cultural resources. To partially address these issues, the National Park Service (NPS) constructed a 300-m-long elevated boardwalk with interconnected viewing platforms in August 2000. To determine what effects the new structures might have on individual bears, we observed bear movements and behaviors before and after construction. We used direct observations and motion-detection cameras to construct temporal-spatial profiles of bear activity. Although bear numbers were similar (59 bears in 2000 and 56 bears in 2001) and bear activity within the greater Brooks River area did not differ (P = 0.62, n = 29) between the 2 years of this study, trail crossings in the vicinity of the new structures decreased 78% (7,436 crossings in 2000 and 1,646 crossings i...

Shoreline areas provide early season foraging opportunities for coastal bears in Alaska. We investigated use by brown bears (Ursus arctos) of soft-shelled (Mya arenaria) and Pacific razor (Siliqua patula) clams at Katmai National Park, Alaska, USA, to identify the potential importance of these clams to bears. We used direct observations of bear foraging behavior in the summers of 1998, 1999, and 2001 to model the nutritional importance of clamming behavior. We also used previously described models to estimate the relative importance of clamming and vegetative foraging in meeting the maintenance requirements of bears. At the harvest rate that we observed (0.69 ± 0.46 clams/min), bears achieved higher rates of digestible energy intake than those foraging on vegetation. Although clams are available for only a few hours per day, bears could significantly reduce their total daily foraging time by utilizing clams. Smaller single bears and females with dependent young were the most represented groups of...

Throughout their circumpolar range, pregnant female polar bears ( Ursus maritimus ) create snow dens in which they give birth to altricial cubs. Because polar bear neonates are born in such an undeveloped state, their survival requires a long, undisturbed period of in-den development. To mitigate human impacts on denning bears, it is necessary to understand the chronology of denning, the behaviors of denning bears, and their sensitivity to human activities. Since 2002, we have studied the den emergence behaviors of polar bears in northern Alaska; however, we moved from using on-site observers (2002 – 03) to using autonomous video systems (2005 – 08). Here we compare the duration, activity budgets, and behaviors of polar bears to see whether observation methods affected their activities. Camera systems recorded nearly 10 times the data per den recorded by human observers (526 h/den and 57 h/den respectively). We found no difference between the two study periods in emergence dates, duration at den sites, abandonment dates, or activity budgets for polar bears. We observed a 16-fold reduction in the number of bear-human interactions when using cameras instead of human observers. There was, however, a marked increase in the intensity of response when using cameras (125 m) as compared to observers in blinds (400 m). An understanding of these activity patterns can be used to manage human activities near dens so as to minimize disturbance.

Brown bear-human interactions were observed in 1993, 1995, and 1997 at Kulik River in Katmai National Park and Preserve, Alaska. We analyzed these interactions using survival analysis, creating survival curves for the time that bears remained on the river in the presence, and absence, of human activity. Bear-only survival curves did not vary significantly between years ( p = 0.067). Ninety-seven percent of bears left the river within 70 minutes of arrival in all years. Temporal patterns of bear activity were unaffected by the presence of humans as long as the bears did not share river zones with humans ( p = 0.062 to p = 0.360). When people and bears did not share river zones, 38.6% (1993), 36.0% (1995), and 37.0% (1997) of bears remained on the river for at least 10 minutes after arrival. In contrast, when people and bears shared river zones, fewer bears remained on the river after the first 10 minutes, with 28.6% (1993), 25.0% (1995), and 32.6% (1997) observed in each year. We conclude that human activity displaced 26.0% (1993), 30.5% (1995), and 12.0% (1997) of the bears using the river, which otherwise would likely have remained longer. Over the three years of study, habituation to human activity may account for observed changes in bears' use of the river.

The crystal structure of a mutant protein of a class A beta-lactamase from Staphylococcus aureus PC1, in which Asp179 is replaced by an asparagine (P54), has been determined and refined at 2.3-A resolution (1 A = 0.1 nm). The resulting crystallographic R factor [formula: see text] are the observed and calculated structure factor amplitudes) is 0.181 for 12289 reflections with I greater than or equal to sigma (I) within the 6.0-2.3-A resolution range. The mutated residue is located at the C-terminus of an extensive loop (the omega-loop), remote from the active site, and results in a drastically reduced activity. Examination of the native and P54 structures reveals that the overall fold is similar, except that there is substantial disorder of the omega-loop of P54. This is a consequence of the elimination of a salt bridge between Asp179 and Arg164 that links the two ends of the omega-loop in native beta-lactamase. It is associated with a difference in side-chain conformation between Asn179 in P54 and Asp179 in the native structure. An alternate interaction occurs in P54 between Asn179 and Ala69, adjacent to the catalytic Ser70. This disorder affects catalysis since some of the disordered residues, in particular Glu166, form part of the active site.(ABSTRACT TRUNCATED AT 250 WORDS)

Various methods were investigated for assessing the relationship between wind-hardened snow ( upsik ) and forage availability to reindeer. Mean bottom area of individual craters was not a function of depth, hardness or integrated hardness. Individual crater area was partially dependent on specific cratering time (r2 = .60). Cratering time per active period increased with integrated snow hardness (r2 = .88). Number of craters and total area cratered increased with decreasing site hardness. Reindeer always cratered microsites of lesser depth and hardness than found in the general feeding site. A threefold decrease in snow hardness resulted in a fourfold increase in forage availability. Key words: Rangifer , snow hardness, snow depth, forage availability

We describe several encounters between Brown Bears (Ursus arctos) and Gray Wolves (Canis lupus) that were observed at Katmai National Park and Preserve in southwest Alaska. Katmai Brown Bears and Gray Wolves were observed interacting in a variety of behavioral modes that ranged from agonistic to tolerant. These observations provide additional insight regarding the behavioral plasticity associated with bear-wolf interactions.

Thiafentanil is a potent synthetic opioid anesthetic being developed for wildlife anesthesia. Thiafentanil was tested for safety and efficacy on free-ranging pronghorn (Antilocapra americana) inhabiting F. E. Warren Air Force Base in southeastern Wyoming. Pronghorn were darted with pre-measured dosages of either 4.0 or 5.0 mg of thiafentanil without (group 1) or with (group 2) the addition of 25.0 mg xylazine Seventeen pronghorn were captured in group 1 and 14 pronghorn in group 2. There were no differences between groups for capture times or physiological parameters (P ≥ 0.21). Anesthetic induction was rapid for both groups (≤ 2.7 ± 0.4 min) as was recovery after antagonism (≤ 0.7 ± 0.07 min). The dosage of thiafentanil administered was 0.10 ± 0.005 mg/kg and the dosage of xylazine was 0.56 ± 0.03 mg/kg. Anesthesia in both groups was characterized by muscle rigidity and rapid, shallow respiration. Twenty-five pronghorn were radiocollared and survived ≥21 days after capture. One adult male in group 1 died during capture. Thiafentanil was considered more effective on pronghorn than carfentanil-xylazine, ketamine-xylazine, or tiletamine-zolazepam-xylazine anesthetic regimens.

Activities of free-ranging reindeer (Rangifer tarandus) on the Seward Peninsula, Alaska were studied to determine 24-hour behaviour patterns and budgets in winter. Use of daytime active-rest data to predict nighttime behaviour resulted in as much as 37% underestimate of nighttime resting and 37% overestimate of nighttime activity. Three active-rest cycles occurred daily, synchronous with photoperiod.Tjuefiretimers adferdsmønster- og budsjett hos fritt beitende reinsdyr om vinteren.Abstract in Norwegian / Sammendrag: Aktiviteter hos fritt beitende reinsdyr {Rangifer tarandus) på Seward Peninsula, Alaska ble undersøkt for bestemmelse av 24 timers adferdsmønster og -budsjett om vinteren. Bruk av dagtids data for aktivitets-hvile til å forutsi nattlig adferd resulterte i 37% underestimering av natt-hvile og 37% overes-timering av natt-aktivitet. Tre aktivitet-hvile cykler inntraff daglig, synkront med fotoperiode.Vapaana laiduntavan poron vuorokautinen kayttaytyminen ja budjetti talvella.Abstract in Finnish / Yhteenveto: Vapaana laiduntavan poron (Rangifer tarandus) aktiivisuutta tutkittiin Sewardin niemimaalla Alaskassa mààrittàmàllà 24 tunnin kayttaytymismallit ja budjetit talvella. Kàyttàmàllâ pàivàajan aktiivisu-us - lepo -tietoja yôajan kåyttåytymisen ennustamiseen ne alittivat jopa 30%:lla yollisen lepoajan ja ylitti-våt 40%:lla yôajan aktiivisuuden. Påivittain esiintyi kolme aktiivisuus - lepo -sykliå samanaikaisesti valo-jaksojen kanssa.