Artykuły w czasopismach: „Brown bear (Ursus arctos)”

1

Elgmork, Kåre, i Even Tjørve. "Brown bear Ursus arctos scavenging patterns". Wildlife Biology 1, nr 1 (styczeń 1995): 239–42. http://dx.doi.org/10.2981/wlb.1995.0029.

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Vougiouklakis, Theodore. "Fatal Brown Bear (Ursus arctos) Attack". American Journal of Forensic Medicine and Pathology 27, nr 3 (wrzesień 2006): 266–67. http://dx.doi.org/10.1097/01.paf.0000220930.00053.43.

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Britton, Ann P., Julie Bidulka, Andrea Scouras, Helen Schwantje i Tomy Joseph. "Fatal hepatic sarcocystosis in a free-ranging grizzly bear cub associated with Sarcocystis canis–like infection". Journal of Veterinary Diagnostic Investigation 31, nr 2 (30.01.2019): 303–6. http://dx.doi.org/10.1177/1040638719826627.

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We describe herein fatal hepatic sarcocystosis in a free-ranging grizzly bear ( Ursus arctos horribilis) cub with apicomplexan infection of the liver and brain, both demonstrating 100% homology for Sarcocystis canis and S. arctosi. Fatal hepatic sarcocystosis in dogs has been etiologically associated with intrahepatic schizonts of S. canis. In black and polar bears, a S. canis–like organism produces schizonts in the liver and massive hepatic necrosis. Although intramuscular sarcocysts, taxa S. arctosi and S. ursusi, have been described in healthy brown and black bears, respectively, they have not been detected in bears with hepatic sarcocystosis, to our knowledge, and it is currently unknown whether bears represent an aberrant or intermediate host.

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Yoon, Byung Il, Jung Keun Lee, Jin Hyun Kim, Nam Shik Shin, Soo Wahn Kwon, Gi Hwan Lee i Dae Yong Kim. "Lymphosarcoma in a brown bear (Ursus arctos)". Journal of Veterinary Science 2, nr 2 (2001): 143. http://dx.doi.org/10.4142/jvs.2001.2.2.143.

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Laikre, Linda, Robert Andrén, Hans-Ove Larsson i Nils Ryman. "Inbreeding depression in brown bear Ursus arctos". Biological Conservation 76, nr 1 (1996): 69–72. http://dx.doi.org/10.1016/0006-3207(95)00084-4.

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Wilk, Randall J., John W. Solberg, Vernon D. Berns i Richard A. Sellers. "Brown Bear, Ursus arctos, with six young". Canadian field-naturalist 102, nr 3 (1988): 541–43. http://dx.doi.org/10.5962/p.356603.

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Marinković, Darko, Jòzsef Özvegy, Milan Aničić, Ivana Vučićević, Slađan Nešić i Vladimir Kukolj. "Gastric Dilatation and Volvulus in Brown Bear (Ursus arctos)". Acta Veterinaria 66, nr 3 (1.09.2016): 422–28. http://dx.doi.org/10.1515/acve-2016-0036.

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Abstract Gastric dilatation and volvulus is a life-threatening condition characterized by rapid accumulation of food and gases that cause displacement and distension of the stomach. The large and giant, deep-chested breeds of dogs are at higher risk for developing the gastric dilatation and volvulus. Uncommonly, it can also develop in cats, but it is also described in free-range polar bears. A case of gastric dilatation and volvulus in a brown bear (Ursus arctos) is described in this paper. This case was characterized by lack of any previous symptoms, sudden death, as well as macroscopic findings during necropsy - twisted distended stomach, congested displaced spleen and necrotic gastric wall. According to the available data this is the first described case report of the gastric dilatation and volvulus in brown bear (Ursus arctos).

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Radisic, B., M. Sindicic, D. Huber, J. Kusak, T. Gomercic, D. Vnuk, D. Maticic i A. Slavica. "Ovariectomy of a brown bear (Ursus arctos): a case report". Veterinární Medicína 55, No. 7 (17.08.2010): 353–57. http://dx.doi.org/10.17221/2965-vetmed.

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Reproductive control is regularly implemented in bear facilities to prevent crowding of enclosures and surplus animals. Ovariectomy may represent an efficient method of sterilizing bears yet has not been reported in the literature. A 73 kg female brown bear, age two years and three months, was anesthetized for ovariectomy with tiletamin and zolazepam (Zoletil<sup>®</sup>, Virbac S.A., Carros Cedex, France) and medetomidin hydrochloride (Domitor<sup>®</sup>, Pfizer Animal Health, New York, USA). A 25 cm midline incision that extended from the umbilicus to the pubic brim was made. The suspensory ligament was stretched and blunt dissected so that ovaries in bursa were exposed on the surgical field. A "Figure 8" ligature was placed between two forcepses and a circumferential ligature was placed around proximal forceps at the ovarian pedicle. Another "Figure 8" ligature was placed between two forcepses and a circumferential ligature was placed around distal forceps at the cranial tip of the uterine horn. No surgical complications occurred, and no complications have transpired during the 12 month post-operative period.

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Cronin, Matthew A., Steven C. Amstrup, Gerald W. Garner i Ernest R. Vyse. "Interspecific and intraspecific mitochondrial DNA variation in North American bears (Ursus)". Canadian Journal of Zoology 69, nr 12 (1.12.1991): 2985–92. http://dx.doi.org/10.1139/z91-421.

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We assessed mitochondrial DNA variation in North American black bears (Ursus americanus), brown bears (Ursus arctos), and polar bears (Ursus maritimus). Divergent mitochondrial DNA haplotypes (0.05 base substitutions per nucleotide) were identified in populations of black bears from Montana and Oregon. In contrast, very similar haplotypes occur in black bears across North America. This discordance of haplotype phylogeny and geographic distribution indicates that there has been maintenance of polymorphism and considerable gene flow throughout the history of the species. Intraspecific mitochondrial DNA sequence divergence in brown bears and polar bears is lower than in black bears. The two morphological forms of U. arctos, grizzly and coastal brown bears, are not in distinct mtDNA lineages. Interspecific comparisons indicate that brown bears and polar bears share similar mitochondrial DNA (0.023 base substitutions per nucleotide) which is quite divergent (0.078 base substitutions per nucleotide) from that of black bears. High mitochondrial DNA divergence within black bears and paraphyletic relationships of brown and polar bear mitochondrial DNA indicate that intraspecific variation across species' ranges should be considered in phylogenetic analyses of mitochondrial DNA.

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Balseiro, Ana, Luis J. Royo, Elena Gayo, Ramón Balsera, Olga Alarcia i Juan F. García Marín. "Mortality Causes in Free-Ranging Eurasian Brown Bears (Ursus arctos arctos) in Spain 1998–2018". Animals 10, nr 9 (31.08.2020): 1538. http://dx.doi.org/10.3390/ani10091538.

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This work summarizes the mortality cases of twenty-five free-ranging Eurasian wild brown bears (Ursus arctos arctos) from the Cantabrian mountain range submitted for necropsy in Asturias and Castilla y León (northwestern Spain) from 1998 to 2018. Mortality cases were classified both caused by (i) “non-human intervention” or “human intervention” causes and based on (ii) “non-infectious” or “infectious” etiology. In four cases (16%) it was not possible to determine the cause of death due to the inadequate preservation of collected specimens or insufficient tissue availability. Based on “non-human intervention” or “human intervention” causes, fourteen of the 21 (66.7%) brown bears died as a consequence of “non-human intervention” due to traumatic lesions (fights, unknown traumas or infanticide), infectious canine hepatitis, neoplasia or mushroom poisoning. In contrast, seven (33.3%) brown bears died by “human intervention” due to illegal hunting (shooting or snare), handling (during transit in an attempt to reintroduce a bear back into the wild) or strychnine poisoning. Based on “non-infectious” or “infectious” etiology, twelve of the 21 (57.1%) brown bears died due to “non-infectious” causes, namely traumatic lesions such as shooting, snare, fighting or infanticide, handling, strychnine poisoning, mushroom poisoning or neoplasia. The remaining nine (42.9%) animals died due to “infectious” diseases which included gangrenous myositis, infectious canine hepatitis or septicemia. In six of those cases traumatic lesions caused by non-human or human activities were complicated with bacterial infection (clostridiosis and septicemia) which finally caused the death of those animals. Additionally, exertional myopathy was observed in the handled animal and in one bear found in a snare. In a free-ranging population of Eurasian brown bear from the Cantabrian mountain range, main causes of death are attributed to non-human related traumatic lesions and infectious diseases (primary developed such as infectious canine hepatitis or secondary developed such as clostridiosis or septicemia) which is in contrast to previously reported data for other bear populations. These data are valuable and may help in the conservation and management of this recovering population.

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Pop, Ioan Mihai, Leonardo Bereczky, Silviu Chiriac, Ruben Iosif, Andreea Nita, Viorel Dan Popescu i Laurențiu Rozylowicz. "Movement ecology of brown bears (Ursus arctos) in the Romanian Eastern Carpathians". Nature Conservation 26 (17.04.2018): 15–31. http://dx.doi.org/10.3897/natureconservation.26.22955.

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Brown bear movement patterns are driven by their opportunistic feeding behaviour, with their complex life history and seasonality playing an important role in habitat selection. Within a large unfragmented forest habitats persisting over decades in the Romanian Carpathians and a prohibitive hunting management during 40 years of communist centralised game management, information about brown bear movements and spatial ecology is lacking. Using data obtained from 13 brown bears fitted with GPS telemetry collars, we estimated home ranges and core activity areas and we investigated the daily, seasonal and altitudinal movements of brown bears in the Eastern Romanian Carpathians and surrounding high hills. The median MCP95% home ranges of brown bears was 629.92 km2 and the median size of core activity areas (estimated as 50% kernel density) was 36.37 km2, with no significant differences between males and females. The mean daily distance travelled, measured as daily displacement length, was 1818 m and an analysis of seasonal movements indicated significant differences between seasons (greatest movements during the Hyperphagia season). The GPS-collared brown bears travelled between a minimum altitude measured at ~234 m and a maximum at ~1634 m. Analysing the spatial overlap between the estimated home range and the game management units (GMU) limits, we obtained a median number of 8 GMUs overlapping totally or partially with estimated home range polygons. Our study, using GPS telemetry, highlights the complex spatial ecology of the brown bear in the Romanian Carpathians, with larger home range size than those estimated in other European brown bear populations and with daily movements that vary by season and within a large altitude range. Our study supports the implementation of brown bear monitoring at a regional scale, rather than focusing on county level GMUs as the monitoring unit.

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Hilderbrand, G. V., S. D. Farley, C. T. Robbins, T. A. Hanley, K. Titus i C. Servheen. "Use of stable isotopes to determine diets of living and extinct bears". Canadian Journal of Zoology 74, nr 11 (1.11.1996): 2080–88. http://dx.doi.org/10.1139/z96-236.

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The potential use of stable-isotope analyses (δ13C and δ15N) to estimate bear diets was assessed in 40-day feeding trials using American black bears (Ursus americanus). Bear plasma and red blood cells have half-lives of ~4 days and ~28 days, respectively. The isotopic signature of bear plasma is linearly related to that of the diet, and with the exception of adipose tissue, there is no isotopic fractionation across bear tissues. Isotopic analyses were used to estimate the diets of three bear populations: Pleistocene cave bears (U. speleaus) in Europe, grizzly bears (Ursus arctos horribilis) inhabiting the Columbia River drainage prior to 1931, and brown bears (U. arctos) of Chichagof and Admiralty islands, Alaska. Cave bears were omnivores with terrestrially produced meat contributing from 41 to 78% (58 ± 14%) of their metabolized carbon and nitrogen. Salmon contributed from 33 to 90% (58 ± 23%) of the metabolized carbon and nitrogen in grizzly bears from the Columbia River drainage. Finally, most brown bears on Chichagof and Admiralty islands feed upon salmon during the late summer and fall; however, a subpopulation of bears exists that does not utilize salmon.

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Große, C., P. Kaczensky i F. Knauer. "Ants: A food source sought by Slovenian brown bears (Ursus arctos)?" Canadian Journal of Zoology 81, nr 12 (1.12.2003): 1996–2005. http://dx.doi.org/10.1139/z03-151.

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In the heavily managed boreal forest of Scandinavia, ants, especially large colonies of red forest ants (Formica spp.), are abundant and brown bears (Ursus arctos) intensively feed on them. In contrast, the beech (Fagus sylvatica) forests of Slovenia provide only suboptimal habitat for ants and large ant colonies are virtually absent. To quantify how much ant use by brown bears is a matter of availability or preference, we quantified ant availability, species composition, and ant use. The estimated biomass of ants available to brown bears was very low in Slovenia compared with those in Sweden, averaging 135 vs. 9600 g/ha, respectively. Nevertheless, the frequency of occurrence of ants in Slovenian brown bear scats was high, averaging 85% and accounting for 25% of the ingested dry mass during the summer, which was nearly as much as their frequency of occurrence in Swedish brown bear scats during the summer. Although brown bears in Slovenia had year-round access to artificial feeding sites and the availability of ants is only about 1% of the biomass found in Sweden, they consumed about 50% of the quantity of ants compared with the brown bears in Sweden. Our results show that ants are an important and sought-after food source for brown bears in Slovenia, and the occurrence of ants should be considered in habitat-suitability models.

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Balseiro, Ana, Laura Polledo, José Tuñón i Juan Francisco García Marín. "Anencephaly and Severe Myelodysplasia in a Stillborn Brown Bear (Ursus arctos arctos)". Animals 12, nr 18 (8.09.2022): 2345. http://dx.doi.org/10.3390/ani12182345.

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Malformations in the development of the neural tube have been described to be associated with different aetiologies, such as genetic factors, toxic plants, chemical products, viral agents, or hyperthermia. A twenty-four-year-old female Eurasian brown bear (Ursus arctos arctos), permanently in captivity and kept under food and management control, gave birth to a stillborn cub at the end of gestation. Several malformations resulting from the anomalous development of the neural tube, not previously reported in bears, were observed, such as anencephaly, hypoplasia, micromyelia, severe myelodysplasia, syringomyelia, and spina bifida. Multiple canal defects (e.g., absence) were also observed in the spinal cord. In some regions, the intradural nerve roots surrounded the spinal cord in a diffuse and continuous way. The aetiology remains unidentified, although the advanced age of the mother and/or folic acid deficit might have been the possible causes of this disorder. Supplements of folate given to the mother before and during early pregnancy may have reduced the incidence of neural tube defects. That supplementation should be considered when the reproduction of bears is to occur in captivity, in order to prevent the loss of future generations of this endangered species.

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RICHTER, JANE. "Brown Bear (Ursus arctos) from Kainsbakke, East Jutland". Journal of Danish Archaeology 5, nr 1 (styczeń 1986): 125–34. http://dx.doi.org/10.1080/0108464x.1986.10589962.

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Deecke, Volker B. "Tool-use in the brown bear (Ursus arctos)". Animal Cognition 15, nr 4 (25.02.2012): 725–30. http://dx.doi.org/10.1007/s10071-012-0475-0.

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Gomes-Alves, S., M. Alvarez, M. Nicolas, C. Martínez-Rodríguez, S. Borragán, C. A. Chamorro, L. Anel i P. de Paz. "Salvaging urospermic ejaculates from brown bear (Ursus arctos)". Animal Reproduction Science 150, nr 3-4 (listopad 2014): 148–57. http://dx.doi.org/10.1016/j.anireprosci.2014.09.007.

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Leonard, Saoirse A., Claire L. Risley i Samuel T. Turvey. "Could brown bears ( Ursus arctos ) have survived in Ireland during the Last Glacial Maximum?" Biology Letters 9, nr 4 (23.08.2013): 20130281. http://dx.doi.org/10.1098/rsbl.2013.0281.

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Brown bears are recorded from Ireland during both the Late Pleistocene and early–mid Holocene. Although most of the Irish landmass was covered by an ice sheet during the Last Glacial Maximum (LGM), Irish brown bears are known to have hybridized with polar bears during the Late Pleistocene, and it is suggested that the Irish brown bear population did not become extinct but instead persisted in situ through the LGM in a southwestern ice-free refugium. We use historical population modelling to demonstrate that brown bears are highly unlikely to have survived through the LGM in Ireland under any combination of life-history parameters shown by living bear populations, but instead would have rapidly become extinct following advance of the British–Irish ice sheet, and probably recolonized Ireland during the end-Pleistocene Woodgrange Interstadial from a closely related nearby source population. The time available for brown bear–polar bear hybridization was therefore restricted to narrow periods at the beginning or end of the LGM. Brown bears would have been extremely vulnerable to extinction in Quaternary habitat refugia and required areas substantially larger than southwestern Ireland to survive adverse glacial conditions.

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Smith, Tom S., Steven T. Partridge i John W. Schoen. "Interactions of Brown Bears, Ursus arctos, and Gray Wolves, Canis lupus, at Katmai National Park and Preserve, Alaska". Canadian Field-Naturalist 118, nr 2 (1.04.2004): 247. http://dx.doi.org/10.22621/cfn.v118i2.922.

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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.

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Boulygina, Eugenia, Fedor Sharko, Maksim Cheprasov, Maria Gladysheva-Azgari, Natalia Slobodova, Svetlana Tsygankova, Sergey Rastorguev i in. "Ancient DNA Reveals Maternal Philopatry of the Northeast Eurasian Brown Bear (Ursus arctos) Population during the Holocene". Genes 13, nr 11 (27.10.2022): 1961. http://dx.doi.org/10.3390/genes13111961.

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Significant palaeoecological and paleoclimatic changes that took place during Late Pleistocene—Early Holocene transition are considered important factors that led to megafauna extinctions. Unlike many other species, the brown bear (Ursus arctos) has survived this geological time. Despite the fact that several mitochondrial DNA clades of brown bears became extinct at the end of the Pleistocene, this species is still widely distributed in Northeast Eurasia. Here, using the ancient DNA analysis of a brown bear individual that inhabited Northeast Asia in the Middle Holocene (3460 ± 40 years BP) and comparative phylogenetic analysis, we show a significant mitochondrial DNA similarity of the studied specimen with modern brown bears inhabiting Yakutia and Chukotka. In this study, we clearly demonstrate the maternal philopatry of the Northeastern Eurasian U. arctos population during the several thousand years of the Holocene.

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Teslovych, M. V., i D. A. Krychevska. "Geoinformation modeling of potentially important territories for the brown bear's stay in the Transcarpathian region". Man and Environment. Issues of Neoecology, nr 39 (26.06.2023): 117–31. http://dx.doi.org/10.26565/1992-4224-2023-39-11.

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Purpose. Search for important areas for the presence of the brown bear (Ursus arctos) within the Transcarpathian region using geoinformation modeling tools to optimize the boundaries of the structural elements of the econetwork. Methods. Geoinformation modeling, geospatial analysis, processing of stock materials of environmental protection services. Results. In order to delineate potentially important areas for the presence of the brown bear (Ursus arctos) within the Transcarpathian region, a comprehensive assessment of the natural environment was carried out using geoinformation modeling tools. This modeling involved a preliminary analysis of the suitability for the life of the species of the following five parameters: types of land cover, proximity of non-forest biotopes to forest, high-altitude bioclimatic zones, degrees of dismemberment of the terrain, distance from settlements and roads. As a result of the integral assessment of these parameters, a cartographic model "Integral suitability of biotopes for the presence of the brown bear (Ursus arctos)" was obtained, which also demonstrated the habitats recorded by experts and the places of registration of the species. It was established that the total area of territories that are potentially suitable for the brown bear (Ursus arctos) within Transcarpathian region is 574.6 thousand hectares, and covers about 45.1% of the territory of the region. The largest number of such habitats is concentrated in the mountainous southwestern part of the region within the orographic ecoregion of the elevated dissected highlands. The most suitable and suitable biotopes, formed as a result of modeling, are also found within the boundaries of Gorganska Verhovyna (on the border of Transcarpathian and Ivano-Frankivsk regions), which belongs to the ecoregion of elevated lowlands. The simulated territories correlate well enough with localities where real signs of the distribution of the species have been recorded. At the second stage of research, in accordance with the chosen methodology, a cartographic model of "Potentially important areas for the presence of the brown bear" was obtained, on which the population, reproduction and other areas, as well as key areas of the region's eco-network and nature protection areas were outlined. Spatial features of the location of population and breeding areas in other morphogenic ecoregions of the Carpathians were also characterized, natural and anthropogenic obstacles and threats to the species' migration and survival were identified. It is noted that the natural conditions of the border are favorable for the migration of mammals from Romania, Slovakia and Poland, which is also confirmed by monitoring studies conducted by environmental protection institutions, forestry and hunting management, etc. Conclusions. The Transcarpathian region has favorable conditions for the existence of the brown bear (Ursus Arctos), in particular, a large share of forest ecosystems, the presence of hard-to-reach areas, a decrease in the population of small mountain villages, etc. However, the constant development of recreational and energy infrastructure can lead to the fragmentation of the natural environment. Therefore, the areas outlined by us, which are important for the presence of the brown bear (Ursus arctos), can be the basis for optimizing the boundaries of the structural elements of the eco-network of the mountainous part of the Transcarpathian region. In the future, it is necessary to continue monitoring studies on the presence of the brown bear within the key territories of the Zakarpattia econetwork and to more clearly delimit ecological corridors with the implementation of measures to comply with the norms of environmental protection restrictions.

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Rinker, David C., Natalya K. Specian, Shu Zhao i John G. Gibbons. "Polar bear evolution is marked by rapid changes in gene copy number in response to dietary shift". Proceedings of the National Academy of Sciences 116, nr 27 (17.06.2019): 13446–51. http://dx.doi.org/10.1073/pnas.1901093116.

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Polar bear (Ursus maritimus) and brown bear (Ursus arctos) are recently diverged species that inhabit vastly differing habitats. Thus, analysis of the polar bear and brown bear genomes represents a unique opportunity to investigate the evolutionary mechanisms and genetic underpinnings of rapid ecological adaptation in mammals. Copy number (CN) differences in genomic regions between closely related species can underlie adaptive phenotypes and this form of genetic variation has not been explored in the context of polar bear evolution. Here, we analyzed the CN profiles of 17 polar bears, 9 brown bears, and 2 black bears (Ursus americanus). We identified an average of 318 genes per individual that showed evidence of CN variation (CNV). Nearly 200 genes displayed species-specific CN differences between polar bear and brown bear species. Principal component analysis of gene CN provides strong evidence that CNV evolved rapidly in the polar bear lineage and mainly resulted in CN loss. Olfactory receptors composed 47% of CN differentiated genes, with the majority of these genes being at lower CN in the polar bear. Additionally, we found significantly fewer copies of several genes involved in fatty acid metabolism as well asAMY1B, the salivary amylase-encoding gene in the polar bear. These results suggest that natural selection shaped patterns of CNV in response to the transition from an omnivorous to primarily carnivorous diet during polar bear evolution. Our analyses of CNV shed light on the genomic underpinnings of ecological adaptation during polar bear evolution.

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Baryshnikov, G. F. "Late pleistocene Ursidae and Mustelidae remains (Mammalia, Carnivora) from Geographical Society Cave in the Russian Far East". Proceedings of the Zoological Institute RAS 319, nr 1 (25.03.2015): 3–22. http://dx.doi.org/10.31610/trudyzin/2015.319.1.3.

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The paleontological collection from Geographical Society Cave located in southern part of Primorskii Territory is found to comprise 5 species of ursids and mustelids: Ursus arctos, Meles anakuma, Martes zibellina, Gulo gulo and Lutra lutra. Bone remains of brown bear (Ursus arctos) predominate; scant tooth-marks of large carnivores on their surfaces suggest bears to have been only occasional prey, dying mainly when overwintering in the cave. The presence of Asian badger (Meles anakuma) and true otter (Lutra lutra), whose findings are not known northwardly, provide the possibility to regard southern regions of the Russian Far East as a refuge, where these species survived during the Late Pleistocene.

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Fuchs, Boris, Koji Yamazaki, Alina L. Evans, Toshio Tsubota, Shinsuke Koike, Tomoko Naganuma i Jon M. Arnemo. "Heart rate during hyperphagia differs between two bear species". Biology Letters 15, nr 1 (styczeń 2019): 20180681. http://dx.doi.org/10.1098/rsbl.2018.0681.

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Hyperphagia is a critical part of the yearly cycle of bears when they gain fat reserves before entering hibernation. We used heart rate as a proxy to compare the metabolic rate between the Asian black bear ( Ursus thibetanus ) in Japan and the Eurasian brown bear ( Ursus arctos ) in Sweden from summer into hibernation. In the hyperphagic period, black bears feed on fat- and carbohydrate-rich hard masts whereas brown bears feed on sugar-rich berries. Availability of hard masts has quantitative and spatial annual fluctuations, which might require increased activity and result in intraspecific stress. Using generalized additive mixed models we analysed the differences in heart rate between the two species. Black bears had decreased heart rates during summer but had doubled heart rate values throughout the hyperphagic period compared to brown bears. This letter illustrates the different physiological consequences of seasonal differences in food availability in two species of the same genus dealing with the same phenological challenge.

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Paczkowski, John, Ivan V. Seryodkin i Vladimir V. Zhakov. "BROWN BEAR (URSUS ARCTOS) (CARNIVORA, MAMMALIA) DENS OF THE KRONOTSKY NATURE RESERVE". Povolzhskiy Journal of Ecology 17, nr 1 (2018): 101–5. http://dx.doi.org/10.18500/1684-7318-2018-1-101-105.

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Winer, J. N., B. Arzi, S. Döring, P. H. Kass i F. J. M. Verstraete. "Dental and Temporomandibular Joint Pathology of the North American Brown Bear ( Ursus arctos horribilis , Ursus arctos middendorffi and Ursus arctos sitkensis )". Journal of Comparative Pathology 157, nr 2-3 (sierpień 2017): 90–102. http://dx.doi.org/10.1016/j.jcpa.2017.06.006.

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Find’o, S., M. Skuban, M. Kajba, J. Chalmers i M. Kalaš. "Identifying attributes associated with brown bear (Ursus arctos) road-crossing and roadkill sites". Canadian Journal of Zoology 97, nr 2 (luty 2019): 156–64. http://dx.doi.org/10.1139/cjz-2018-0088.

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Habitat fragmentation caused by transportation infrastructure is an issue of growing concern worldwide. We show how secondary roads may affect landscape permeability for brown bears (Ursus arctos Linnaeus, 1758). We focused on identifying environmental variables that govern the selection of road-crossing zones by bears (crossing model). We also investigated whether variables that characterize road-crossing zones differ from those that are typical for bear–vehicle collision sites (collision model). The study area was located in north-central Slovakia. To identify road-crossing sites, we used the GPS fixes of 27 bears and identified 35 bear–vehicle collision sites from a different data set. We used mixed-effects logistic regression to model resource selection at road-crossing sites and to compare bear-crossing sites with bear-kill sites. The crossing model showed that the traffic volume with distance to forest and grassland were the most influential factors in bear selection of road-crossing sites. Results of the collision model indicated that successful road crossings by bears were located at different road sections from vehicle collisions, which differed by a traffic volume of 5000 vehicles/24 h. The outcomes of this study can facilitate improved mitigation measures on secondary roads.

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Ågren, Erik, Arne Söderberg i Torsten Mörner. "Fallot's Tetralogy in a European Brown Bear (Ursus arctos)". Journal of Wildlife Diseases 41, nr 4 (październik 2005): 825–28. http://dx.doi.org/10.7589/0090-3558-41.4.825.

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Nak, Deniz, I. Taci Cangul, Yavuz Nak, Huseyin Cihan i Nureddin Celimli. "Tubulopapillary Mammary Carcinoma in a Brown Bear (Ursus arctos)". Journal of Wildlife Diseases 44, nr 2 (kwiecień 2008): 505–8. http://dx.doi.org/10.7589/0090-3558-44.2.505.

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SUEL, H. "BROWN BEAR (URSUS ARCTOS) HABITAT SUITABILITY MODELLING AND MAPPING". Applied Ecology and Environmental Research 17, nr 2 (2019): 4245–55. http://dx.doi.org/10.15666/aeer/1702_42454255.

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Hadžiomerović, Nedžad, Rizah Avdić, Senad Kovačević, Faruk Tandir i Pamela Bejdić. "Spondyloarthropathy in a captive female brown bear (Ursus arctos)". Journal of Advances in VetBio Science and Techniques 4, nr 3 (31.12.2019): 1–4. http://dx.doi.org/10.31797/vetbio.571424.

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Baryshnikov, G. F. "Late Pleistocene brown bear (Ursus arctos) from the Caucasus". Russian Journal of Theriology 9, nr 1 (21.02.2011): 9–17. http://dx.doi.org/10.15298/rusjtheriol.09.1.02.

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Salomashkina, V. V., M. V. Kholodova, U. A. Semenov, A. S. Muradov i A. Malkhasyan. "Genetic variability of brown bear (Ursus arctos L., 1758)". Russian Journal of Genetics 53, nr 1 (styczeń 2017): 108–17. http://dx.doi.org/10.1134/s1022795416120103.

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STEYAERT, Sam M. J. G., Anders ENDRESTØL, Klaus HACKLÄNDER, Jon E. SWENSON i Andreas ZEDROSSER. "The mating system of the brown bear Ursus arctos". Mammal Review 42, nr 1 (12.04.2011): 12–34. http://dx.doi.org/10.1111/j.1365-2907.2011.00184.x.

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ØSTBYE, EIVIND, STEIN-ERIK LAURITZEN, KJARTAN ØSTBYE i ØYSTEIN WIIG. "Holocene brown bear (Ursus arctos L.) from Norwegian caves". Boreas 35, nr 2 (28.06.2008): 296–316. http://dx.doi.org/10.1111/j.1502-3885.2006.tb01159.x.

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Østbye, Eivind, Stein-Erik Lauritzen, Kjartan Østbye i Øystein Wiig. "Holocene brown bear ( Ursus arctos L.) from Norwegian caves". Boreas 35, nr 2 (1.05.2006): 296–316. http://dx.doi.org/10.1080/03009480600578107.

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Anel, L., M. Álvarez, F. Martínez-Pastor, S. Gomes, M. Nicolás, M. Mata, AF Martínez, S. Borragán, E. Anel i P. de Paz. "Sperm Cryopreservation in Brown Bear (Ursus arctos): Preliminary Aspects". Reproduction in Domestic Animals 43 (październik 2008): 9–17. http://dx.doi.org/10.1111/j.1439-0531.2008.01248.x.

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Pigoli, C., M. Tecilla, A. Bianchi, P. Roccabianca, G. Ghisleni i L. R. Gibelli. "Pheochromocytoma and Malignant Insulinoma in an Eurasian Brown Bear (Ursus arctos arctos)". Journal of Comparative Pathology 174 (styczeń 2020): 163. http://dx.doi.org/10.1016/j.jcpa.2019.10.075.

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Willson, Mary F., i Scott M. Gende. "Seed Dispersal by Brown Bears, Ursus arctos, in Southeastern Alaska". Canadian Field-Naturalist 118, nr 4 (1.10.2004): 499. http://dx.doi.org/10.22621/cfn.v118i4.53.

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Mammals often consume fleshy fruits and disperse significant quantities of the enclosed seeds. In southeastern Alaska, Brown Bears (Ursus arctos) are among the most important dispersers of seeds for the numerous plant species producing fleshy fruits, because these bears are abundant, often eat large quantities of fruit, and commonly excrete seeds in germinable condition. Scat analyses showed that Brown Bears on Chichagof Island ate increasing quantities of fruit through summer and fall. Scats commonly contained several thousand seeds, often of two or more species. Four kinds of seeds of fleshyfruited plants that normally grow in forest understory germinated at similar levels when experimentally deposited (in bear scats) in the two most common habitats (forest and muskeg), suggesting that habitat distribution of these plants is not determined simply by germination patterns. Although seed passage through bear digestive tracts and the composition of scats are known to affect germination rates to some degree, the most important role of bears in seed dispersal is probably transport.

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40

Papadopoulos, E., A. Komnenou, T. Poutachides, P. Heikkinen, A. Oksanen i A. A. Karamanlidis. "Detection of Dirofilaria immitis in a brown bear (Ursus arctos) in Greece". Helminthologia 54, nr 3 (1.09.2017): 257–61. http://dx.doi.org/10.1515/helm-2017-0033.

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SummaryDirofilaria immitis (canine heartworm) is a filarial nematode found in the pulmonary circulation and the heart of susceptible hosts. It represents an important zoonotic vector-borne disease of domestic dogs and several wildlife species. Herein we report for the first time, the finding of Dirofilaria immitis worms in a brown bear killed in a vehicle collision in Northern Greece. The worms were morphologically identified; molecular examination, based on the analysis of the mitochondrial genes 12S (433 bp) and CO1 (610 bp), verified the identification by demonstrating 100% similarity to D. immitis specimens deposited in GenBank. Brown bears in Greece occupy habitats that are shared with the potential wild and domestic hosts and the vectors of D. immitis and thus may be particularly susceptible to this parasite. This report contributes to the knowledge of dirofilariosis spread in Europe and on the epidemiological threats that may affect the survival of the endangered brown bear in Greece.

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Ji, Yunrui, Fang Liu, Diqiang Li, Zhiyu Chen i Peng Chen. "Spatial–Temporal Patterns of Sympatric Asiatic Black Bears (Ursus thibetanus) and Brown Bears (Ursus arctos) in Northeastern China". Animals 12, nr 10 (14.05.2022): 1262. http://dx.doi.org/10.3390/ani12101262.

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Studying the spatial and temporal interactions between sympatric animal species is essential for understanding the mechanisms of interspecific coexistence. Both Asiatic black bears (Ursus thibetanus) and brown bears (Ursus arctos) inhabit northeastern China, but their spatial–temporal patterns and the mechanism of coexistence were unclear until now. Camera traps were set in Heilongjiang Taipinggou National Nature Reserve (TPGNR) from January 2017 to December 2017 to collect photos of the two sympatric bear species. The Pianka index, kernel density estimation, and the coefficient of overlap were used to analyze the spatial and temporal patterns of the two sympatric species. Our findings indicated that the spatial overlap between Asiatic black bears and brown bears was low, as Asiatic black bears occupied higher elevations than brown bears. The two species’ temporal activity patterns were similar at sites where only one species existed, yet they were different at the co–occurrence sites. Asiatic black bears and brown bears are competitors in this area, but they can coexist by changing their daily activity patterns. Compared to brown bears, Asiatic black bears behaved more diurnally. Our study revealed distinct spatial and temporal differentiation within the two species in TPGNR, which can reduce interspecific competition and facilitate coexistence between them.

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Boeskorov, G. G., G. F. Baryshnikov, A. N. Tikhonov, A. V. Protopopov, A. I. Klimovsky, S. E. Grigoriev, M. Yu Cheprasov, G. P. Novgorodov, M. V. Shchelchkova i J. Van der Plicht. "New data on the large brown bear (Ursus arctos L., 1758, Ursidae, Carnivora, Mammalia) from the pleistocene of Yakutia". Доклады Академии наук 486, nr 6 (28.06.2019): 685–90. http://dx.doi.org/10.31857/s0869-56524866685-690.

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New finds of the fossil brown bear (Ursus arctos L., 1758) remains from the territory of Yakutia have been investigated: skulls and mandibular bones. The new finds are of exceptionally large sizes, most of their measurements far exceed those of not only the modern brown bear from Yakutia, but also the maximum values of the largest representatives of modern subspecies from Eurasia, U. a. beringianus and U. a. piscator. Analysis of various data indicates that the giant brown bear existed in the north of Yakutia during the Karginian interstadial of the Late Pleistocene.

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Garcia-Macias, V., F. Martinez-Pastor, M. Alvarez, P. Paz, S. Borragan, M. Celada, E. Anel i L. Anel. "219 MORPHOMETRIC CHARACTERIZATION OF EPIDIDYMAL AND EJACULATED SPERMATOZOA FROM BROWN BEAR (URSUS ARCTOS)". Reproduction, Fertility and Development 18, nr 2 (2006): 217. http://dx.doi.org/10.1071/rdv18n2ab219.

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Sperm morphology is an useful characteristic for estimating potential fertility. Currently, we are obtaining baseline information on various aspects of reproduction in the brown bear (Ursus arctos) with the intention of using the knowledge to establish a germplasm bank for the species. In the present report, we describe the results obtained using assisted sperm morphology analysis (ASMA, Sperm Class Analyzer®; Microptic S.L, Barcelona, Spain) to analyze the morphological differences in epidydimal (caput, corpus, and cauda) and ejaculated brown bear spermatozoa. A post-mortem epididymal sperm sample was obtained from an adult brown bear after accidental death. The epididymides were excised, washed, and dissected into the three major segments; caput, corpus and cauda. Then multiple incisions were made in the tissue to allow migration of spermatozoa into the surrounding medium. Semen was collected by electroejaculation from five adult brown bears living in a semi-free ranging environment in the Cabarceno Park (Cantabria, Spain). Anesthesia was induced using tiletamine + zolazepan (Zoletil 100®; Virbac, Carras, France; 7 mg/kg), and ketamine (Imalgene 1000®; Rhone Merieux, Lyon, France; 2 mg/kg). The electroejaculation unit (PT Electronics®; Boring, Oregon) was connected to a 3-lateral electrode transrectal probe (26 mm in diameter, 320 mm in length). Ejaculation occurred at 6–10 V/250–300 mA. For head morphometry assessment, sperm samples were fixed in glutaraldehyde and slides were smeared and air-dried for 2 h. The samples were then stained with Diff-Quik® staining (37°C; 10 min in the red component and 15 min in the blue component). The area, perimeter, length and width, and ellipticity (length/width) of heads were measured from at least 100 spermatozoa/slide. As shown in Table 1, values obtained for each measure were similar in both epididymal and ejaculated spermatozoa. These results provide normal morphometry values for brown bear spermatozoa, a potentially useful characteristic for predicting fertility. Table 1. Head morphometry for epididymis and ejaculated bear sperm (mean ± SD) This work was supported in part by CANTUR S.A. and CICYT (CGL 2004–0278/BOS).

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Piédallu, Blaise, Pierre-Yves Quenette, Nicolas Bombillon, Adrienne Gastineau, Christian Miquel i Olivier Gimenez. "Determinants and patterns of habitat use by the brown bear Ursus arctos in the French Pyrenees revealed by occupancy modelling". Oryx 53, nr 2 (10.07.2017): 334–43. http://dx.doi.org/10.1017/s0030605317000321.

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AbstractThe Pyrenean brown bear Ursus arctos population in the mountains between France and Spain is one of the smallest and most threatened populations of large carnivores in Europe. We assessed trends in brown bear habitat use in the Pyrenees and investigated the underlying environmental and anthropogenic drivers. Using detection/non-detection data collected during 2008–2014 through non-invasive methods, we developed dynamic occupancy models, accounting for local colonization and extinction processes. We found two non-connected core areas of occupancy, one in the west and the other in the centre of the Pyrenees, with a significant decrease in habitat use overall during 2008–2014. We also found a negative correlation between human density and bear occupancy, in agreement with previous studies on brown bear habitat suitability. Our results confirm the Critically Endangered status of the Pyrenean population of brown bears.

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Moiseeva, T. A. "Behavioral activity of Ursus arctos brown bear in zoo conditions". IOP Conference Series: Earth and Environmental Science 677, nr 5 (1.03.2021): 052068. http://dx.doi.org/10.1088/1755-1315/677/5/052068.

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Revenko, Igor A. "Brown Bear (Ursus arctos piscator) Reaction to Humans on Kamchatka". Bears: Their Biology and Management 9 (1994): 107. http://dx.doi.org/10.2307/3872689.

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Balseiro, Ana, Álvaro Oleaga, Laura Polledo, Gorka Aduriz, Raquel Atxaerandio, Nekane Kortabarria i Juan F. García Marín. "Clostridium sordellii in a Brown Bear (Ursus arctos) from Spain". Journal of Wildlife Diseases 49, nr 4 (październik 2013): 1047–51. http://dx.doi.org/10.7589/2013-03-065.

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MATSUDA, Kazuya, Yongjin QIU, Yoshio KAWAMURA, Hiromi SUZUKI, Yuko TAKITA, Hideyuki SAKAMOTO, Kazuyoshi SASAKI i Hiroyuki TANIYAMA. "Hepatocellular Carcinoma in a Hokkaido Brown Bear (Ursus arctos yesoensis)". Journal of Veterinary Medical Science 72, nr 9 (2010): 1213–16. http://dx.doi.org/10.1292/jvms.10-0034.

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MURAKAMI, Tomoaki, Yoshiyasu KOBAYASHI, Shiori CHIBA, Yuki KURAUCHI, Hideyuki SAKAMOTO, Motoki SASAKI i Takane MATSUI. "Humeral Chondrosarcoma in a Hokkaido Brown Bear (Ursus arctos yesoensis)". Journal of Veterinary Medical Science 74, nr 9 (2012): 1195–97. http://dx.doi.org/10.1292/jvms.12-0083.

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Fröbert, Ole, Kjeld Christensen, Åsa Fahlman, Sven Brunberg, Johan Josefsson, Eva Särndahl, Jon E. Swenson i Jon M. Arnemo. "Platelet function in brown bear (Ursus arctos) compared to man". Thrombosis Journal 8, nr 1 (2010): 11. http://dx.doi.org/10.1186/1477-9560-8-11.

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