Hibernation is an adaptation that helps many animals to conserve energy during food shortage in winter. Brown bears double their fat depots during summer and use these stored lipids during ...hibernation. Although bears seasonally become obese, they remain metabolically healthy. We analyzed the microbiota of free-ranging brown bears during their active phase and hibernation. Compared to the active phase, hibernation microbiota had reduced diversity, reduced levels of Firmicutes and Actinobacteria, and increased levels of Bacteroidetes. Several metabolites involved in lipid metabolism, including triglycerides, cholesterol, and bile acids, were also affected by hibernation. Transplantation of the bear microbiota from summer and winter to germ-free mice transferred some of the seasonal metabolic features and demonstrated that the summer microbiota promoted adiposity without impairing glucose tolerance, suggesting that seasonal variation in the microbiota may contribute to host energy metabolism in the hibernating brown bear.
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•Bear microbiota composition differs seasonally between hibernation and active phase•Blood metabolites differ seasonally in the brown bear•The bear gut microbiota promote energy storage during summer
Sommer et al. show that the microbiota and serum metabolites in brown bears differ seasonally between hibernation and active phase. Colonization of mice with a bear microbiota promoted increased adiposity. These findings suggest that seasonal microbiota variation may contribute to metabolism of the hibernating brown bear.
Recent research highlights the ecological importance of individual variation in behavioural predictability. Individuals may not only differ in their average expression of a behavioural trait (their ...behavioural type) and in their ability to adjust behaviour to changing environmental conditions (individual plasticity), but also in their variability around their average behaviour (predictability). However, quantifying behavioural predictability in the wild has been challenging due to limitations of acquiring sufficient repeated behavioural measures.
We here demonstrate how common biologging data can be used to detect individual variation in behavioural predictability in the wild and reveal the coexistence of highly predictable individuals along with unpredictable individuals within the same population.
We repeatedly quantified two behaviours—daily movement distance and diurnal activity—in 62 female brown bears Ursus arctos tracked across 187 monitoring years. We calculated behavioural predictability over the short term (50 consecutive monitoring days within 1 year) and long term (across monitoring years) as the residual intra‐individual variability (rIIV) of behaviour around the behavioural reaction norm. We tested whether predictability varies systematically across average behavioural types and whether it is correlated across functionally distinct behaviours, that is, daily movement distance and amount of diurnal activity.
Brown bears showed individual variation in behavioural predictability from predictable to unpredictable individuals. For example, the standard deviation around the average daily movement distance within one monitoring year varied up to fivefold from 1.1 to 5.5 km across individuals. Individual predictability for both daily movement distance and diurnality was conserved across monitoring years. Individual predictability was correlated with behavioural type where individuals which were on average more diurnal and mobile were also more unpredictable in their behaviour. In contrast, more nocturnal individuals moved less and were more predictable in their behaviour. Finally, individual predictability in daily movement distance and diurnality was positively correlated, suggesting that individual predictability may be a quantitative trait in its own regard that could evolve and is underpinned by genetic variation.
Unpredictable individuals may cope better with stochastic events and unpredictability may hence be an adaptive behavioural response to increased predation risk. Coexistence of predictable and unpredictable individuals may therefore ensure adaptable and resilient populations.
Unpredictable behaviour can be an adaptive response to increased predation risk. Movement data revealed the first account of long‐term individual variation in behavioural predictability in a hunted brown bear population. Diurnal and mobile individuals, which are more likely to encounter humans during the day behaved more unpredictable than nocturnal bears.
•Compared harvested areas to wildfires in relation to grizzly bear foods.•A variety of foods occurred at greater frequency in harvested areas.•Digestible energy was highest in very young and young ...(~5 and 20 yrs) age-classes.•No differences in digestible energy between disturbance types.•Differences in digestible energy evident between age-classes.
Grizzly bear (Ursus arctos) populations residing in interior ecosystems of North America are known to frequent harvested areas and areas burnt by wildfires, as both disturbances encourage growth of early seral vegetation preferred by them. This is especially evident in places where there is a paucity of large natural openings and areas with a long history of wildfire suppression, such as the foothill forests of west-central Alberta. Little has been done, however, to directly quantify and compare grizzly bear food-supply in both disturbance types and at early stages of forest regeneration. In this paper, we explore whether harvested areas can act as surrogates to wildfires for grizzly bear food-supply in west-central Alberta, Canada. We sampled known fruit-bearing and herbaceous grizzly bear foods for their occurrence, productivity, and digestible energy supply among post-harvest, post-fire, and mature forests disturbance types, and across very young (~5 yrs), young (~20 yrs), and mid (~60 yrs) age-classes for post-harvest and post-fire disturbances. A variety of foods occurred at greater frequency in post-harvest stands, with the occurrence of most foods explained by the main effects of disturbance and age-class, or in combination with one environmental covariate. Overall, fruit productivity and digestible energy from fruits were highest in the young age-class, whereas forb productivity and digestible energy from forbs were highest in the very young age-class. There were no significant differences in total available digestible energy (fruit + forb) between post-harvest and post-fire stands within any age-class, but significant differences were evident between age-classes. These results suggest that harvested areas can potentially act as a surrogate to wildfires in relation to grizzly bear food-supply, but human access remains a key challenge for harvests given their association with roads. We suggest that harvested areas could be used as management tool to maintain or enhance grizzly bear food-supply and thus contribute to population recovery efforts, especially in areas of wildfire suppression.
1. Habitat choice is an evolutionary product of animals experiencing increased fitness when preferentially occupying high-quality habitat. However, an ecological trap (ET) can occur when an animal is ...presented with novel conditions and the animal's assessment of habitat quality is poorly matched to its resulting fitness. 2. We tested for an ET for grizzly (brown) bears using demographic and movement data collected in an area with rich food resources and concentrated human settlement. 3. We derived measures of habitat attractiveness from occurrence models of bear food resources and estimated demographic parameters using DNA mark-recapture information collected over 8 years (2006-2013). We then paired this information with grizzly bear mortality records to investigate kill and movement rates. 4. Our results demonstrate that a valley high in both berry resources and human density was more attractive than surrounding areas, and bears occupying this region faced 17% lower apparent survival. Despite lower fitness, we detected a net flow of bears into the ET, which contributed to a study-wide population decline. 5. This work highlights the presence and pervasiveness of an ET for an apex omnivore that lacks the evolutionary cues, under human-induced rapid ecological change, to assess tradeoffs between food resources and human-caused mortality, which results in maladaptive habitat selection.
•HEV-specific antibodies were detected in 16 zoo-housed animal species.•Highest seroprevalences were found in suids (33.3%) and carnivores (27.0%).•RNA of ratHEV was detected in a Syrian brown bear ...(Ursus arctos syriacus).•Closely related ratHEV strains were found in wild Norway rats from the same location.•Zoo animals have to be considered as hosts of HEV or HEV-related viruses.
Hepatitis E virus (HEV) is the causative agent of hepatitis E, an emerging infectious disease of humans. HEV infections have also been described in various animal species. Whereas domestic pigs and wild boars are well-known animal reservoirs for HEV, the knowledge on natural HEV infection in zoo animals is scarce so far. Here, we analysed 244 sera from 66 mammal species derived from three zoos in Germany using a commercial double antigen sandwich ELISA. HEV-specific antibodies were detected in 16 animal species, with the highest detection rates in suids (33.3%) and carnivores (27.0%). However, RNA of the human pathogenic HEV genotypes 1–4 was not detected in the serum samples from suids or carnivores. Using a broad spectrum RT-PCR, a ratHEV-related sequence was identified in a sample of a female Syrian brown bear (Ursus arctos syriacus). Subsequent serum samples within a period of five years confirmed a HEV seroconversion in this animal. No symptoms of hepatitis were recorded. In a follow-up investigation at the same location, closely related ratHEV sequences were identified in free-living Norway rats (Rattus norvegicus), whereas feeder rats (Rattus norvegicus forma domestica) were negative for HEV-specific antibodies and RNA. Therefore, a spillover infection of ratHEV from free-living Norway rats is most likely. The results indicate that a wide range of zoo animals can be naturally infected with HEV or HEV-related viruses. Their distinct role as possible reservoir animals for HEV and sources of HEV infection for humans and other animals remains to be investigated.
Scientific management of wildlife requires confronting the complexities of natural and social systems. Uncertainty poses a central problem. Whereas the importance of considering uncertainty has been ...widely discussed, studies of the effects of unaddressed uncertainty on real management systems have been rare. We examined the effects of outcome uncertainty and components of biological uncertainty on hunt management performance, illustrated with grizzly bears (Ursus arctos horribilis) in British Columbia, Canada. We found that both forms of uncertainty can have serious impacts on management performance. Outcome uncertainty alone--discrepancy between expected and realized mortality levels--led to excess mortality in 19% of cases (population-years) examined. Accounting for uncertainty around estimated biological parameters (i.e., biological uncertainty) revealed that excess mortality might have occurred in up to 70% of cases. We offer a general method for identifying targets for exploited species that incorporates uncertainty and maintains the probability of exceeding mortality limits below specified thresholds. Setting targets in our focal system using this method at thresholds of 25% and 5% probability of overmortality would require average target mortality reductions of 47% and 81%, respectively. Application of our transparent and generalizable framework to this or other systems could improve management performance in the presence of uncertainty.
Abstract Hibernation is a key adaptation for coping with unfavorable climatic conditions and low food availability in areas with severe winter conditions. While understanding the physiology and ...phenology of this adaptation has received considerable attention, comparatively little information is available on how hibernation will be affected by changing climate conditions. We used GPS telemetry data from 20 free‐ranging brown bears monitored over 31 winters between 2007 and 2022, to identify behavioral strategies of bears during winter. We applied behavioral change point analysis to quantify brown bears’ hibernation phenology in a population close to the bear's southern latitudinal range limit in Europe where supplementary food is available to bears year‐round. We observed winter behavior patterns that varied across age and reproductive classes but also within individuals between winters. Among 31 winter events, we registered six cases in which bears exhibited a single hibernation/stationary period and 19 events where hibernation was split into up to five stationary periods. Moreover, six winter events did not show behaviors consistent with hibernation and individuals remained partly or completely active throughout winter. The movement of these active bears decreased with increasing snow depth. In addition, these winter‐active bears showed higher fidelity to supplementary feeding sites during the winter period compared to the rest of the year. Our data suggest that an abundance of human‐provided food resources during winter may facilitate the emergence of different wintering strategies in brown bears. Furthermore, supplemental feeding sites in combination with predicted mild winters and prolonged natural food availability suggest that the use of hibernation as an energy‐saving strategy to overcome severe environmental conditions may decrease in the future.
Edwardsiella (E) tarda belongs to the Enterobacteriaceae family and is a motile, gram-negative, rod-shaped, facultative anaerobe regarded as an opportunistic and food-borne pathogen in animals and ...humans. A 21-year- old male Eurasian brown bear (Ursus arctos arctos) died suddenly without any preliminary signs. Necropsy performed according to standard protocol revealed swollen abdomen with hemorrhagic congestions of the gastroenteric organs, ascites, and hemorrhagic exudates around the mouth. The liver showed discolor- ation, along with a severely swollen and multiple hemorrhages of the spleen, an elongated gallbladder, and a congested cortex and medullar lesion of kidneys. The stomach contained semi-liquid exudates and undigested chicken exuding a decayed odor. The stomach membranes were dark-gray in color with several cysts in the fundus lesions. Rod-shaped bacteria were found in the major organs by Giemsa staining, identified as E. tarda using a biochemical rapid diagnostic identification kit. KCI Citation Count: 0
Habitat selection is a fundamental behaviour that links individuals to the resources required for survival and reproduction. Although natural selection acts on an individual’s phenotype, research on ...habitat selection often pools inter-individual patterns to provide inferences on the population scale. Here, we expanded a traditional approach of quantifying habitat selection at the individual level to explore the potential for consistent individual differences of habitat selection. We used random coefficients in resource selection functions (RSFs) and repeatability estimates to test for variability in habitat selection. We applied our method to a detailed dataset of GPS relocations of brown bears (Ursus arctos) taken over a period of 6 years, and assessed whether they displayed repeatable individual differences in habitat selection toward two habitat types: bogs and recent timber-harvest cut blocks. In our analyses, we controlled for the availability of habitat, i.e. the functional response in habitat selection. Repeatability estimates of habitat selection toward bogs and cut blocks were 0.304 and 0.420, respectively. Therefore, 30.4 and 42.0 % of the population-scale habitat selection variability for bogs and cut blocks, respectively, was due to differences among individuals, suggesting that consistent individual variation in habitat selection exists in brown bears. Using simulations, we posit that repeatability values of habitat selection are not related to the value and significance of β estimates in RSFs. Although individual differences in habitat selection could be the results of non-exclusive factors, our results illustrate the evolutionary potential of habitat selection.
The ranges of wolves (Canis lupus) and bears (Ursus arctos) across Europe have expanded recently, and it is important to assess public attitudes toward this expansion because responses toward these ...species vary widely. General attitudes toward an object are good predictors of broad behavioral patterns; thus, attitudes toward wolves and bears can be used as indicators to assess the social foundation for future conservation efforts. However, most attitude surveys toward bears and wolves are limited in scope, both temporally and spatially, and provide only a snapshot of attitudes. To extend the results of individual surveys over a much larger temporal and geographical range so as to identify transnational patterns and changes in attitudes toward bears and wolves over time, we conducted a meta‐analysis. Our analysis included 105 quantitative surveys conducted in 24 countries from 1976 to 2012. Across Europe, people's attitudes were more positive toward bears than wolves. Attitudes toward bears became more positive over time, but attitudes toward wolves seemed to become less favorable the longer people coexisted with them. Younger and more educated people had more positive attitudes toward wolves and bears than people who had experienced damage from these species, and farmers and hunters had less positive attitudes toward wolves than the general public. For bears attitudes among social groups did not differ. To inform conservation of large carnivores, we recommend that standardized longitudinal surveys be established to monitor changes in attitudes over time relative to carnivore population development. Our results emphasize the need for interdisciplinary research in this field and more advanced explanatory models capable of capturing individual and societal responses to changes in large carnivore policy and management.
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