Development of On-Shore Behavior Among Polar Bears (\u3ci\u3eUrsus maritimus\u3c/i\u3e) in the Southern Beaufort Sea: Inherited or Learned?

Polar bears (Ursus maritimus) are experiencing rapid and substantial changes to their environment due to global climate change. Polar bears of the southern Beaufort Sea (SB) have historically spent most of the year on the sea ice. However, recent reports from Alaska indicate that the proportion of the SB subpopulation observed on‐shore during late summer and early fall has increased. Our objective was to investigate whether this on‐shore behavior has developed through genetic inheritance, asocial learning, or through social learning. From 2010 to 2013, genetic data were collected from SB polar bears in the fall via hair snags and remote biopsy darting on‐shore and in the spring from captures and remote biopsy darting on the sea ice. Bears were categorized as either on‐shore or off‐shore individuals based on their presence on‐shore during the fall. Levels of genetic relatedness, first‐order relatives, mother–offspring pairs, and father–offspring pairs were determined and compared within and between the two categories: on‐shore versus off‐shore. Results suggested transmission of on‐shore behavior through either genetic inheritance or social learning as there was a higher than expected number of first‐order relatives exhibiting on‐shore behavior. Genetic relatedness and parentage data analyses were in concurrence with this finding, but further revealed mother–offspring social learning as the primary mechanism responsible for the development of on‐shore behavior. Recognizing that on‐shore behavior among polar bears was predominantly transmitted via social learning from mothers to their offspring has implications for future management and conservation as sea ice continues to decline

Use of Subsistence-Harvested Whale Carcasses by Polar Bears in the Southern Beaufort Sea

The availability of a food subsidy has the potential to influence the condition, behavior, fitness, and population dynamics of a species. Since the early 2000s, monitoring efforts along the coast of northern Alaska have indicated a higher proportion of polar bears (Ursus maritimus) of the southern Beaufort Sea (SB) subpopulation coming onshore to feed on subsistence-harvested bowhead whale (Balaena mysticetus) carcasses during the fall and early winter seasons. Concurrently, Indigenous communities annually hunt bowhead whale and deposit the unused remains at localized “bone piles,” creating the potential for human-bear interactions. Our objective was to determine the annual number of polar bears feeding at the bone pile near Kaktovik, Alaska. Using a hair snag surrounding the bone pile, we collected hair samples to identify individual bears via microsatellite genotypes during 2011 – 14. We used capture-mark-recapture data in the POPAN open-population model to estimate the number of bears visiting the bone pile. We estimated that as many as 72 (SE = 9) and 76 (SE = 10) male and female polar bears, respectively, used the bone pile located at Kaktovik, Alaska, in 2012, which represents approximately 16% of the SB polar bear subpopulation. It will be important to monitor the number of bears using the bone pile and subsequent human-bear interactions and conflicts along the northern coast of Alaska, if sea ice continues to recede.L’existence de subventions alimentaires a la possibilité d’influencer l’état, le comportement, la condition physique et la dynamique de la population d’une espèce. Depuis le début des années 2000, les efforts de surveillance déployés sur la côte nord de l’Alaska ont laissé entrevoir une plus grande proportion d’ours polaires (Ursus maritimus) de la sous-population du sud de la mer de Beaufort venant sur le littoral pour manger les carcasses des baleines boréales (Balaena mysticetus) pêchées à des fins de subsistance pendant les saisons de l’automne et du début de l’hiver. En même temps, les collectivités autochtones chassent les baleines boréales tous les ans et déposent leurs restes dans des « tas d’ossements », ce qui crée la possibilité d’interactions entre les humains et les ours. Notre objectif consistait à déterminer le nombre annuel d’ours polaires qui s’alimentent au tas d’ossements situé près de Kaktovik, en Alaska. De 2011 à 2014, à l’aide d’un piège à poils placé près du tas d’ossements, nous avons recueilli des échantillons de poils afin d’identifier les ours individuels au moyen de génotypes microsatellites. Nous avons employé les données de capture-marquage-recapture du modèle de population ouverte POPAN pour estimer le nombre d’ours se rendant au tas d’ossements. Nous avons estimé que jusqu’à 72 (ET = 9) et 76 (ET = 10) ours polaires mâles et femelles, respectivement, ont utilisé le tas d’ossements de Kaktovik, en Alaska, en 2012, ce qui représente environ 16 % de la sous-population d’ours polaires du sud de la mer de Beaufort. Il sera important de surveiller le nombre d’ours qui utilisent le tas d’ossements de même que les interactions et les conflits entre les humains et les ours qui s’ensuivront sur la côte nord de l’Alaska si la glace de mer continue de reculer

High winds and melting sea ice trigger landward movement in a polar bear population of concern

Some animal species are responding to climate change by altering the timing of events like mating and migration. Such behavioral plasticity can be adaptive, but it is not always. Polar bears (Ursus maritimus) from the southern Beaufort Sea subpopulation have mostly remained on ice year-round, but as the climate warms and summer sea ice declines, a growing proportion of the subpopulation is summering ashore. The triggers of this novel behavior are not well understood. Our study uses a parametric time-to-event model to test whether biological and/or time-varying environmental variables thought to influence polar bear movement and habitat selection also drive decisions to swim ashore. We quantified the time polar bears spent occupying offshore sea ice of varying ice concentrations. We evaluated variations in the ordinal date bears moved to land with respect to local environmental conditions such as sea ice concentration and wind across 10 years (2005–2015). Results from our study suggest that storm events (i.e., sustained high wind speeds) may force polar bears from severely degraded ice habitat and catalyze seasonal movements to land. Unlike polar bears long adapted to complete summer ice melt, southern Beaufort Sea bears that summer ashore appear more tolerant of poor-quality sea ice habitat and are less willing to abandon it. Our findings provide a window into emergent, climatically mediated behavior in an Arctic marine mammal vulnerable to rapid habitat decline

Importance of resource selection and social behavior to partitioning of hostile space by sympatric canids

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

Diet-driven mercury contamination is associated with polar bear gut microbiota

7openInternationalInternational coauthor/editorThe gut microbiota may modulate the disposition and toxicity of environmental contaminants within a host but, conversely, contaminants may also impact gut bacteria. Such contaminant-gut microbial connections, which could lead to alteration of host health, remain poorly known and are rarely studied in free-ranging wildlife. The polar bear (Ursus maritimus) is a long-lived, wide-ranging apex predator that feeds on a variety of high trophic position seal and cetacean species and, as such, is exposed to among the highest levels of biomagnifying contaminants of all Arctic species. Here, we investigate associations between mercury (THg; a key Arctic contaminant), diet, and the diversity and composition of the gut microbiota of polar bears inhabiting the southern Beaufort Sea, while accounting for host sex, age class and body condition. Bacterial diversity was negatively associated with seal consumption and mercury, a pattern seen for both Shannon and Inverse Simpson alpha diversity indices (adjusted R2 = 0.35, F1,18 = 8.00, P = 0.013 and adjusted R2 = 0.26, F1,18 = 6.04, P = 0.027, respectively). No association was found with sex, age class or body condition of polar bears. Bacteria known to either be involved in THg methylation or considered to be highly contaminant resistant, including Lactobacillales, Bacillales and Aeromonadales, were significantly more abundant in individuals that had higher THg concentrations. Conversely, individuals with higher THg concentrations showed a significantly lower abundance of Bacteroidales, a bacterial order that typically plays an important role in supporting host immune function by stimulating intraepithelial lymphocytes within the epithelial barrier. These associations between diet-acquired mercury and microbiota illustrate a potentially overlooked outcome of mercury accumulation in polar bears.openWatson, S.; McKinney, M.A.; Pindo, M.; Bull, M.; Atwood, T.C.; Hauffe, H.C.; Perkins, S.E.Watson, S.; Mckinney, M.A.; Pindo, M.; Bull, M.; Atwood, T.C.; Hauffe, H.C.; Perkins, S.E

Sentinel-based Surveillance of Coyotes to Detect Bovine Tuberculosis, Michigan

Bovine tuberculosis (TB) is endemic in white-tailed deer (Odocoileus virginianus) in the northeastern portion of Michigan’s Lower Peninsula. Bovine TB in deer and cattle has created immense fi nancial consequences for the livestock industry and hunting public. Surveillance identified coyotes (Canis latrans) as potential bio-accumulators of Mycobacterium bovis, a finding that generated interest in their potential to serve as sentinels for monitoring disease risk. We sampled 175 coyotes in the bovine TB–endemic area. Fifty-eight tested positive, and infection prevalence by county ranged from 19% to 52% (statistical mean 33%, SE 0.07). By contrast, prevalence in deer (n = 3,817) was lower (i.e., 1.49%; Mann-Whitney U4,4 = 14, pM. bovis by 40%. As a result of reduced sampling intensity, sentinel coyote surveys have the potential to be practical indicators of M. bovis presence in wildlife and livestock

Sentinel-based Surveillance of Coyotes to Detect Bovine Tuberculosis, Michigan

Coyotes could be used as sentinels to detect Mycobacterium bovis in the wild