Infanticide is a significant evolutionary force influencing carnivore behaviours, as it is one of the primary contributors to offspring mortality. Female multimale mating, which creates paternal ...uncertainty, is known to reduce infanticide. We propose that two crucial steps are needed for this strategy to work in solitary species like brown bears, Ursus arctos. First, after mating, females should choose dens within their mating area (step 1), boosting the chances of encountering potential fathers of cub(s) after den emergence in spring. However, the efficacy of this strategy hinges on males' fidelity to the same mating areas from one year to the next (step 2). Our study confirmed that pregnant females consistently selected dens within their mating areas, with significant overlap (around 90%) between areas used by females with cubs and their mating zones. Males also demonstrated fidelity (over 65%) to mating areas over 2 consecutive years. Infanticide significantly shapes the sociospatial ecology of female brown bears, a phenomenon that can carry nutritional costs for females with cubs, and influence settlement patterns near human shields to increase reproductive success. Additionally, in hunted populations, removing resident males can trigger an influx of potentially infanticidal bears from elsewhere.
•Infanticide represents one of the main causes of offspring mortality in carnivores.•Natural selection has favoured several behavioural counterstrategies in females.•Female bear multimale mating reduces infanticide by creating paternal uncertainty.•Males show fidelity to the same mating areas from one year to the next.•Females with cubs remain in the mating area to increase chances of meeting fathers.
This study presents a documented case of a bear (Ursus arctos) predator attack on a foal, employing osteological analysis to determine the manner of death. By analyzing bone surface and structural ...modifications, we distinguish between injuries inflicted during the killing event and those resulting from scavenging or post-mortem consumption. A variety of bone modifications are recorded and documented, with a particular emphasis on a linear fracture on the body of the C4 vertebra and a double arc puncture on the proximal metaphysis of the left metatarsal. The former wound signifies a direct attack, while the latter signifies a defensive injury. This study case underscores the importance of taphonomic analysis in detecting instances of wild animal attacks on domestic livestock. Particularly in scenarios where visual evidence and conventional necropsies concentrating on soft tissue examination fail to confirm mauling occurrences, taphonomy provides valuable insights.
Cave bear (Ursus spelaeus), brown bear (Ursus arctos), and Neanderthals were potential competitors for environmental resources (shelters and food) in Europe. In order to reinforce this view and ...contribute to the ongoing debate on late Neanderthal behavior, we present evidence from zooarchaeological and taphonomic analyses of bear bone remains discovered at Rio Secco Cave and Fumane Cave in northeast Italy, an extended geographic area north of the Adriatic Sea. The remains from both caves come from layers dated to 49-42 ky cal. BP, and suggest close interactions between humans and bears, with data not only limited to the association of Mousterian lithic artifacts with numerous bear remains, but also the detection of clearly preserved traces of human modification such as cut and percussion marks, which enable a reconstruction of the main steps of fur recovery and the butchering process. Examples of Neanderthal bear exploitation are extremely sporadic in Europe, and Grotta Rio Secco and Grotta Fumane can be considered rare cases of remain accumulations generated by the human predation of bears of varied age classes during or near the end of hibernation. All of this evidence suggests that bears had a strategic role in the nomadic economy of Neanderthal hunting groups.
•Cave bear, brown bear and Neanderthals were potential competitors for environmental shelters and food.•Examples of Neanderthal bear exploitation are extremely sporadic in Western Eurasia.•Bone taphonomy from caves in Southern Alps suggests Neanderthals hunted cave and brown bears.•Ongoing debate on late Neanderthal behavior is feeded.
Species ranges are changing in response to human-related disturbances and often management and conservation decisions must be based on incomplete information. In this context, species distribution ...models (SDMs) represent the most widely used tool, but they often lack any reference to demographic performance of the population under study, spatial structure of the habitat patches, or connectivity at the landscape level.
Combining a multi-state SDM with a landscape pattern analysis and a mortality model, we developed a spatially-explicit, integrated model to assist and inform conservation planning for the Apennine brown bear in central Italy. We identified 15 critical habitat areas, potentially hosting 76 adult female bears. Many of these areas are, however, characterized by high levels of human-related mortality, making them attractive sink-like areas. Structural connectivity was higher in the northern part of the study area while only limited connectivity characterizes the core area, where most of the bears currently live.
Our integrated model indicates that the conservation of this relict and isolated bear population is a realistic conservation goal, as we estimated that 192–270 bears could live across the Apennines. Our modelling framework enhances the biological realism of traditional SDMs and provides a conservation planning tool that integrates habitat suitability, mortality risk (as a component of the total demographic performance) and structural connectivity among habitat patches at the landscape scale. It is particularly suited for endangered species living in a human-modified landscapes where establishing a realistic and spatially explicit conservation goal would facilitate pro-active management.
Large carnivores under assault in Alaska Ripple, William J; Miller, Sterling D; Schoen, John W ...
PLoS biology,
01/2019, Letnik:
17, Številka:
1
Journal Article
Recenzirano
Odprti dostop
In Alaska, gray wolves (Canis lupis), brown bears (Ursus arctos), and black bears (U. americanus) are managed in most of the state in ways intended to significantly reduce their abundance in the ...expectation of increasing hunter harvests of ungulates. To our knowledge, Alaska is unique in the world because this management priority is both widespread and mandated by state law. Large carnivore management in Alaska is a reversion to outdated management concepts and occurs without effective monitoring programs designed to scientifically evaluate impacts on predator populations. Large carnivore management in Alaska should be based on rigorous science including the status and trends of carnivore populations.
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.
The tick Amblyomma testudinarium Koch, 1844 (Acari: Ixodidae) is known as a vector of several pathogens such as Rickettsia tamurae and severe fever with thrombocytopenia syndrome (SFTS) virus. This ...tick species is present in many Asian countries, including Japan, where its distribution is limited to the warm areas of Kanto region and the southwestern region. The present study reports the recovery of a partially engorged A. testudinarium from a wild brown bear captured in Shari town, Hokkaido. In addition to morphological identification, the specimen was genetically characterized by the complete mitochondrial genome sequencing. The results showed that the length of the obtained mitogenome is 14,835 bp that encodes 13 protein-coding, two ribosomal RNA (rRNA) (12S and 16S), and 22 transfer RNA genes with two non-coding control regions. The phylogenetic analysis indicated that our sample clustered with A. testudinarium from Nara, Japan, but separated from A. testudinarium from China. Although the introduction of the tick through livestock transportation cannot be ruled out, the detection of A. testudinarium in Hokkaido prefecture, which is separated from the main island where A. testudinarium is present in the south, may suggest the introduction by migratory birds. This study provides important insights on the distribution and host range of A. testudinarium. This will be useful for the future taxonomic analysis of ticks based on the complete mitogenome sequencing. To our knowledge, this is the northernmost detection point of the tropical tick A. testudinarium.
•Amblyomma testudinarium was collected from a brown bear captured in Hokkaido.•The complete mitochondrial genome of Amblyomma testudinarium was determined.•The tick was negative by PCR/RT-PCR for piroplasms, rickettsiae, and SFTSV infection.
Large mammals that occur in low densities, particularly in the high-altitude areas, are globally threatened due to fragile climatic and ecological envelopes. Among bear species, the Himalayan brown ...bear (Ursus arctos isabellinus) has a distribution that is restricted to Himalayan highlands with relatively small and fragmented populations. To date, very little scientific information on the Himalayan brown bear, which is vital for the conservation of the species and the management of its habitats, especially in protected areas of the landscape, is available. The present study aims to understand the effectiveness of existing Himalayan Protected Areas in terms of representativeness for the conservation of Himalayan brown bear (HBB), an umbrella species in high-altitude habitats of the Himalayan region. We used the ensemble approach of the species distribution model and then assessed biological connectivity to predict the current and future distribution and movement of HBB in climate change scenarios for the year 2050. Approximately 33 protected areas (PAs) currently possess suitable habitats. Our model suggests a massive decline of approximately 73.38% and 72.87% under 4.5 and 8.5 representative concentration pathway (RCP) respectively in the year 2050 compared with the current distribution. The predicted change in suitability will result in loss of habitats from thirteen PAs; eight will become completely uninhabitable by the year 2050, followed by loss of connectivity in the majority of PAs. Habitat configuration analysis suggested a 40% decline in the number of suitable patches, a reduction in large habitat patches (up to 50%) and aggregation of suitable areas (9%) by 2050, indicating fragmentation. The predicted change in geographic isotherm will result in loss of habitats from thirteen PAs, eight of them will become completely inhabitable. Hence, these PAs may lose their effectiveness and representativeness in achieving the very objective of their existence or conservation goals. Therefore, we recommend adaptive spatial planning for protecting suitable habitats distributed outside the PA for climate change adaptation.
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•Ensemble distribution modeling used to predict the distribution of Himalayan Brown Bear.•Significant reduction in suitable habitat and biological corridors is predicted in the climate change scenario•Protected areas in the Himalayan region of India and Pakistan may lose their effectiveness and representativeness.•Adaptive spatial planning for protecting habitats outside the protected areas will be vital to mitigate climate change.
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.
The brown bear (
) is one of the survivors of the Late Quaternary megafauna extinctions. However, despite being widely distributed across the Holarctic, brown bears have experienced extensive range ...reductions, and even extirpations in some geographical regions. Previous research efforts using genetic data have provided valuable insights into their evolutionary history. However, most studies have been limited to contemporary individuals or mitochondrial DNA, limiting insights into population processes that preceded the present. Here, we present genomic data from two Late Pleistocene brown bears from Honshu, Japan and eastern Siberia, and combine them with published contemporary and ancient genomes from across the Holarctic range of brown bears to investigate the evolutionary relationships among brown bear populations through time and space. By including genomic data from Late Pleistocene and Holocene individuals sampled outside the current distribution range, we uncover diversity not present in contemporary populations. Notably, although contemporary individuals display geographically structured populations most likely driven by isolation-by-distance, this pattern varies among the ancient samples across different regions. The inclusion of ancient brown bears in our analysis provides novel insights into the evolutionary history of brown bears and contributes to understanding the populations and diversity lost during the Late Quaternary.
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