Tubulopapillary mammary carcinoma in a brown bear (Ursus arctos)

A 28-yr-old, nulliparous female brown bear (Ursus arctos) at the Karacabey Ovakurusu Bear Sanctuary presented with an enlargement of the mammary gland. Three other nodules were also noted in the proximity of the mammary gland and over the vulva. Clinical, hematologic, ultrasonographic, and radiologic examinations were performed; the enlarged mammary gland was removed and the other masses were also excised. Histopathologic examination revealed tubulopapillary carcinoma of the mammary gland, and the other masses were diagnosed as epidermoid cysts. This is the first reported case of tubulopapillary mammary carcinoma accompanied by epidermoid cysts in a bear.     

Fallot's tetralogy in a European brown bear (Ursus arctos)

A congenital heart malformation was diagnosed in a free-ranging adult female European brown bear (Ursus arctos) found dead due to intraspecific violence. At necropsy, the heart had all four features of Fallot's tetralogy. No further malformations were identified in the animal, which was of normal size and weight for its age, in normal body condition, and had probably borne young. The heart condition was considered to have contributed to death during an attack by another bear.     

Genetic variation and population structure in Scandinavian wolverine (Gulo gulo) populations

Wolverine (Gulo gulo) numbers in Scandinavia were significantly reduced during the early part of the century as a result of predator removal programmes and hunting. Protective legislation in both Sweden and Norway in the 1960s and 1970s has now resulted in increased wolverine densities in Scandinavia. We report here the development of 15 polymorphic microsatellite markers in wolverine and their use to examine the population sub-structure and genetic variability in free-ranging Scandinavian wolverine populations as well as in a sample of individuals collected before 1970. Significant subdivision between extant populations was discovered, in particular for the small and isolated population of southern Norway, which represents a recent recolonization. Overall genetic variability was found to be lower than previously reported for other mustelids, with only two to five alleles per locus and observed heterozygosities (H(O)) ranging from 0.269 to 0.376 across the examined populations, being lowest in southern Norway. Analysis of the mitochondrial DNA control region revealed no variation throughout the surveyed populations. As the historical sample did not show higher levels of genetic variability, our results are consistent with a reduction in the genetic variation in Scandinavian wolverines that pre-dates the demographic bottleneck observed during the last century. The observed subdivision between populations calls for management caution when issuing harvest quotas, especially for the geographically isolated south Norwegian population.     

Seasonal patterns in the physiology of the European brown bear (Ursus arctos arctos) in Finland

The physiological indicators such as body temperature, blood chemistry and hematology of seven European brown bears (Ursus arctos arctos) were used in the present study. They were kept in either the Zoological Garden of University of Oulu (65°N, 25°24'E) or the Ranua Zoological Garden approx. 150 km NE of Oulu. Transmitters with a temperature-dependent pulse rate were implanted subcutaneously or into the abdominal cavity under anesthesia. Our data indicate that the body temperature of the bear decreases during the winter sleep to 4–5°C below the normal level (37.0–37.5°C). The lowest values, 33.1–33.3°C, were measured several times in midwinter. Hematocrit, hemoglobin and erythrocyte counts seem to be higher, and the leucocyte count lower during the denning period than in the awake bear. Plasma N-wastes were lower during the winter sleep than before or after it. The analysed blood parameters showed that plasma catecholamines and thyroid hormones decreased in the fall.     

Capture and medetomidine-ketamine anesthesia of free-ranging wolverines (Gulo gulo)

Capture and anesthesia with medetomidine-ketamine were evaluated in free-ranging wolverines (Gulo gulo) immobilized for marking with radiocollars or intraperitoneal radiotransmitters in Norrbotten, Sweden, during early June 2004 and 2005. Twelve juvenile wolverines were captured by hand and injected with 0.14 +/- 0.03 mg/kg (mean +/- SD) medetomidine and 7.5 +/- 2.0 mg/kg ketamine. Twelve adult wolverines were darted from a helicopter or the ground, or captured by hand. Adults received 0.37 +/- 0.06 mg/kg medetomidine and 9.4 +/- 1.4 mg/kg ketamine. Arterial blood samples were collected between 15 min and 30 min and between 45 min and 60 min after drug administration and immediately analyzed for selected hematologic and plasma variables. Hyperthermia was recorded initially in one juvenile wolverine and 11 adults. Rectal temperature, heart rate, and lactate decreased significantly during anesthesia, whereas hemoglobin oxygen saturation, pH, partial pressure of arterial carbon dioxide, and base excess increased. Adult wolverines darted from a helicopter had a significantly higher rectal temperature, higher glucose and hematocrit values, and a lower heart rate than juveniles captured by hand. Impaired arterial oxygenation was evident in all wolverines. This study provides baseline data on physiologic variables in adult and juvenile wolverines captured with different methods and anesthetized with medetomidine-ketamine.     

Non-invasive genetic study of the endangered Cantabrian brown bear (Ursus arctos)

The Brown Bear (Ursus arctos) population present in the Cantabrian Mountains has suffered a dramatic decline in recent centuries and is now threatened with extinction. This situation has led to the development and implementation of a species recovery plan. To accomplish this plan, we need to improve our knowledge about the ecology, demography and genetics of this population. This paper presents the genetic analysis of the Cantabrian brown bear population using non-invasive samples (faeces and hairs) collected between 2004 and 2006. It was necessary to optimize a set of 18 microsatellite loci and a sex marker (several new multiplex reactions were developed) to obtain a suitable probability of identity among genotypes to work with this small, deeply structured population. Genotyping of 48 individuals was carried out using a two-step PCR protocol to increase the quality of the multilocus genotypes. Validation of genotypes was performed using a multi-tube approach combined with different software programmes to measure their error rate and reliability. Diversity in the Cantabrian population was low (H _e = 0.51) and the population was markedly subdivided into two subpopulations (western and eastern) without current gene flow between them. The level of divergence between the two subpopulations (F _st = 0.41) and the extremely low diversity in the eastern group (H _e = 0.25) indicate that this has had an extremely low effective population size and had been isolated from the main group during the last century. Connectivity between the two subpopulations will be of prime importance for the long-term survival of this species in the Cantabrian Mountains.     

Molecular identification of Taenia spp. in wolves (Canis lupus), brown bears (Ursus arctos) and cervids from North Europe and Alaska

Taenia tapeworms of Finnish and Swedish wolves (Canis lupus) and Finnish brown bears (Ursus arctos), and muscle cysticerci of Svalbard reindeer (Rangifer tarandus platyrhynchus), Alaskan Grant's caribou (Rangifer tarandus granti) and Alaskan moose (Alces americanus) were identified on the basis of the nucleotide sequence of a 396 bp region of the mitochondrial cytochrome c oxidase subunit 1 gene. Two species were found from wolves: Taenia hydatigena and Taenia krabbei. The cysticerci of reindeer, caribou and one moose also represented T. krabbei. Most of the cysticercal specimens from Alaskan moose, however, belonged to an unknown T. krabbei-like species, which had been reported previously from Eurasian elks (Alces alces) from Finland. Strobilate stages from two bears belonged to this species as well. The present results suggest that this novel Taenia sp. has a Holarctic distribution and uses Alces spp. as intermediate and ursids as final hosts.     

Split parturition observed in a captive North American brown bear (Ursus arctos)

Reproductive physiology in North American ursids is characterized by mating from spring to early summer, delayed implantation, and birth during hibernation. During spring 2008, a captive adult female brown bear was mated with two adult males. Pregnancy was determined by elevated progesterone concentrations during late fall before hibernation. Two male cubs were born on December 31, 2008, and a third female cub was born 17 days later on January 16. All were successfully raised and all were confirmed to have identical paternity. When normalized to age, cub growth rates did not differ. To our knowledge, this is the first documented case of markedly different birth dates in a single litter of brown bear cubs.     

Geographic and genetic boundaries of brown bear (Ursus arctos) population in the Caucasus

The taxonomic status of brown bears in the Caucasus remains unclear. Several morphs or subspecies have been identified from the morphological (craniological) data, but the status of each of these subspecies has never been verified by molecular genetic methods. We analysed mitochondrial DNA sequences (control region) to reveal phylogenetic relationships and infer divergence time between brown bear subpopulations in the Caucasus. We estimated migration and gene flow from both mitochondrial DNA and microsatellite allele frequencies, and identified possible barriers to gene flow among the subpopulations. Our suggestion is that all Caucasian bears belong to the nominal subspecies of Ursus arctos. Our results revealed two genetically and geographically distinct maternal haplogroups: one from the Lesser Caucasus and the other one from the Greater Caucasus. The genetic divergence between these haplogroups dates as far back as the beginning of human colonization of the Caucasus. Our analysis of the least‐cost distances between the subpopulations suggests humans as a major barrier to gene flow. The low genetic differentiation inferred from microsatellite allele frequencies indicates that gene flow between the two populations in the Caucasus is maintained through the movements of male brown bears. The Likhi Ridge that connects the Greater and Lesser Caucasus mountains is the most likely corridor for this migration.     

Improved noninvasive genotyping method: application to brown bear (Ursus arctos) faeces

We redesigned new microsatellite primers and one sex‐specific primer for amplification of faecal DNA from brown bears (Ursus arctos). We also combined a semi‐nested polymerase chain reaction (PCR) with a newly developed multiplex preamplification method in order to increase the quality of the amplified DNA fragments. In comparison with a conventional PCR approach, the genotyping error rate was substantially reduced and the amplification rate was increased. This new approach could be transposed to other species where conventional PCR methods experience low success due to limited DNA concentration and/or quality.     

Range and local population densities of brown bear Ursus arctos in Slovenia

Solid understanding of species’ range and local population densities is important for successful wildlife management and research. Specific behavioral and ecological characteristics make brown bear Ursus arctos a difficult species to study. We present a map of range and local population densities of brown bears in Slovenia, made with the use of a new approach similar to voting classifications based on a combination of four datasets: Global Positioning System telemetry data, records of bear removals, systematic and opportunistic direct observations and signs of bear presence, and noninvasive genetic samples. Results indicate that the majority of bears in Slovenia live in Dinaric Mountains in the southern part of the country where local bear population densities exceed 40 bears/100 km². This is one of the highest population densities reported so far for this species worldwide. Population densities decrease towards the north (Alpine region) and are very low along the border with Italy and Austria where almost no females are present. This explains slow past and present expansion of this transboundary bear population into the Alps and should be considered in future bear re-colonization management strategies. Results also showed that data from observations and removals overestimate bear population densities at low values, while mortality and genetic data overestimate population densities in areas with more people. Nevertheless, all data types appeared useful for describing the general bear distribution patterns. Similar approach could be applied to studies of other charismatic or game species, for which several types of data are often available.     

Enzyme‐ and immunohistochemical aspects of skeletal muscle fibers in brown bear (Ursus arctos)

To further elucidate the pattern of MHC isoform expression in skeletal muscles of large mammals, in this study the skeletal muscles of brown bear, one of the largest mammalian predators with an extraordinary locomotor capacity, were analyzed. Fiber types in longissimus dorsi, triceps brachii caput longum, and rectus femoris muscles were determined according to the myofibrillar ATPase (mATPase) histochemistry and MHC isoform expression, revealed by a set of antibodies specific to MHC isoforms. The oxidative (SDH) and glycolytic enzyme (α‐GPDH) capacity of fibers was demonstrated as well. By mATPase histochemistry five fiber types, i.e., I, IIC, IIA, IIAX, IIX were distinguished. Analyzing the MHC isoform expression, we assume that MHC‐I, ‐IIa, and ‐IIx are expressed in the muscles of adolescent bears. MHC‐I isoform was expressed in Type‐I fibers and coexpressed with presumably ‐IIa isoform, in Type‐IIC fibers. Surprisingly, two antibodies specific to rat MHC‐IIa stained those fast fibers, that were histochemically and immunohistochemically classified as Type IIX. This assumption was additionally confirmed by complete absence of fiber staining with antibody specific to rat MHC‐IIb and all fast fiber staining with antibody that according to our experience recognizes MHC‐IIa and ‐IIx of rat. Furthermore, quite high‐oxidative capacity of all fast fiber types and their weak glycolytic capacity also imply for MHC‐IIa and ‐IIx isoform expression in fast fibers of bear. However, in adult, full‐grown animal, only MHC‐I and MHC‐IIa isoforms were expressed. The expression of only two fast isoforms in bear, like in many other large mammals (humans, cat, dog, goat, cattle, and horse) obviously meets the weight‐bearing and locomotor demands of these mammals. J. Morphol., 2009. © 2008 Wiley‐Liss, Inc.     

Capture, anesthesia, and disturbance of free-ranging brown bears (Ursus arctos) during hibernation

We conducted thirteen immobilizations of previously collared hibernating two- to four-year-old brown bears (Ursus arctos) weighing 21-66 kg in central Sweden in winter 2010 and 2011 for comparative physiology research. Here we report, for the first time, an effective protocol for the capture and anesthesia of free-ranging brown bears during hibernation and an assessment of the disturbance the captures caused. Bears were darted in anthill, soil, or uprooted tree dens on eleven occasions, but two bears in rock dens fled and were darted outside the den. We used medetomidine at 0.02-0.06 mg/kg and zolazepam-tiletamine at 0.9-2.8 mg/kg for anesthesia. In addition, ketamine at 1.5 mg/kg was hand-injected intramuscularly in four bears and in six it was included in the dart at 1.1-3.0 mg/kg. Once anesthetized, bears were removed from the dens. In nine bears, arterial blood samples were analyzed immediately with a portable blood gas analyzer. We corrected hypoxemia in seven bears (PaO(2) 57-74 mmHg) with supplemental oxygen. We placed the bears back into the dens and antagonized the effect of medetomidine with atipamezole. Capturing bears in the den significantly increased the risk of den abandonment. One of twelve collared bears that were captured remained at the original den until spring, and eleven, left their dens (mean ± standard deviation) 3.2±3.6 (range 0.5-10.5) days after capture. They used 1.9±0.9 intermediate resting sites, during 6.2±7.8 days before entering a new permanent den. The eleven new permanent dens were located 730±589 m from the original dens. We documented that it was feasible and safe to capture hibernating brown bears, although they behaved differently than black bears. When doing so, researchers should use 25% of the doses used for helicopter darting during the active period and should consider increased energetic costs associated with den abandonment.     

An evaluation of long-term preservation methods for brown bear (Ursus arctos) faecal DNA samples

Relatively few large-scale faecal DNA studieshave been initiated due to difficulties inamplifying low quality and quantity DNAtemplate. To improve brown bear faecal DNA PCRamplification success rates and to determinepost collection sample longevity, fivepreservation methods were evaluated: 90%ethanol, DETs buffer, silica-dried, oven-driedstored at room temperature, and oven-driedstored at –20 °C. Preservationeffectiveness was evaluated for 50 faecalsamples by PCR amplification of a mitochondrialDNA (mtDNA) locus (146 bp) and a nuclear DNA(nDNA) locus (200 bp) at time points of oneweek, one month, three months and six months. Preservation method and storage timesignificantly impacted mtDNA and nDNAamplification success rates. For mtDNA, allpreservation methods had 75% success atone week, but storage time had a significantimpact on the effectiveness of the silicapreservation method. Ethanol preserved sampleshad the highest success rates for both mtDNA(86.5%) and nDNA (84%). Nuclear DNAamplification success rates ranged from 26–88%, and storage time had a significant impacton all methods but ethanol. Preservationmethod and storage time should be importantconsiderations for researchers planningprojects utilizing faecal DNA. We recommendpreservation of faecal samples in 90% ethanolwhen feasible, although when collecting inremote field conditions or for both DNA andhormone assays a dry collection method may beadvantageous.     

On the association of giant short-faced bear (Arctodus simus) and brown bear (Ursus arctos) in late Pleistocene North America

Climate change and human impacts are often implicated in Quaternary megafaunal extinctions. The discovery of associated remains of extinct giant short-faced bears (Arctodus simus) and invading brown bears (Ursus arctos) raises the possibility of competition as another potential factor. We describe fossil remains of both genera from Pellucidar Cave, Vancouver Island, Canada. Analyses of ancient mitochondrial DNA support the identifications of post-cranial brown bear specimens and assign these bears to Clade 4. Our results are consistent with the migration of brown bears from Eastern Beringia to the contiguous United States before the Last Glacial Maximum (LGM) and to Vancouver Island as environmental conditions became favorable after the LGM. Radiocarbon age estimates on these specimens indicate the presence of giant short-faced bears approximately 13.5 thousand calibrated years before present (cal. ka BP; uncalibrated 11,775 ± 30, 11,720 ± 50, and 11,615 ± 30 BP) and of brown bears immediately preceding (～14.5 cal. ka BP; 12,440 ± 35, 12,425 ± 30 BP) and following this time (～13 cal. ka BP; uncal. 11,100 ± 30 BP), suggesting niche partitioning to reduce competition among these species. We suggest that shifts in food availability or quality due to post-glacial vegetation and faunal changes were probably of primary importance in the arrival and the disappearance of giant short-faced bears on Vancouver Island. This study focuses on a key time period and geographic location that is useful in understanding Pleistocene extinctions in North America.     

Food habits and foraging of the brown bear Ursus arctos in central south Norway

Analysis of 134 excrement samples from the brown bear Ursus arctos L in boreal forests m central south Norway found volumes to be largest for Vaccinium spp, herbage Empetrum spp, and Formicidae The most important plant material in volume uptake were herbage, leaves, and mosses, closely followed by berries and seeds All together, plant material amounted to c 85% by volume, Formicidae to c 8%, and domestic sheep to c 7% These values were radically changed by applying correction factors for different nutritional value of food items The importance of large mammals then increased substantially, while the importance of herbage was reduced There was a drastic shift in food composition through the seasons Formicidae and flowers of deciduous trees were prevalent in spring, herbage in early summer, Vaccinium spp and sheep in late summer, and Vaccinium spp and Empetrum spp in autumn     

Nuclear DNA microsatellite analysis of genetic diversity and gene flow in the Scandinavian brown bear (Ursus arctos)

In the 1930s, the Scandinavian brown bear was close to extinction due to vigorous extermination programmes in Norway and Sweden. Increased protection of the brown bear in Scandinavia has resulted in the recovery of four subpopulations, which currently contain close to 1000 individuals. Effective conservation and management of the Scandinavian brown bear requires knowledge of the current levels of genetic diversity and gene flow among the four subpopulations. Earlier studies of mitochondrial DNA (mtDNA) diversity revealed extremely low levels of genetic variation, and population structure that grouped the three northern subpopulations in one genetic clade and the southernmost subpopulation in a second highly divergent clade. In this study, we extended the analysis of genetic diversity and gene flow in the Scandinavian brown bear using data from 19 nuclear DNA microsatellite loci. Results from the nuclear loci were strikingly different than the mtDNA results. Genetic diversity levels in the four subpopulations were equivalent to diversity levels in nonbottlenecked populations from North America, and significantly higher than levels in other bottlenecked and isolated brown bear populations. Gene flow levels between subpopulations ranged from low to moderate and were correlated with geographical distance. The substantial difference in results obtained using mtDNA and nuclear DNA markers stresses the importance of collecting data from both types of genetic markers before interpreting data and making recommendations for the conservation and management of natural populations. Based on the results from the mtDNA and nuclear DNA data sets, we propose one evolutionarily significant unit and four management units for the brown bear in Scandinavia.