The development of wildlife genetics combined with non-invasive sampling might be both an economic benefit for the society and a benefit for the survival of the threatened species. The aims of this ...study are to develop a quality assured approach for DNA profiling of brown bears (
Ursus arctos) in Northern Europe using material from non-invasive sampling and to generate a population database that can be used for conservation management as well as a reference database for forensic purposes. Non-invasive sampling was performed by the collection of scats in the field and by using sets of hair traps in a grid pattern in specified geographical areas. Genotypes from 12 STR loci were determined for 232 Norwegian bears. Initial analysis of the entire sample indicated a high level of substructure. Thus, the sample was divided into four geographically different populations consisting of 206 individuals for further validation of the markers. Ten STRs (G1D, G10L, Mu05, Mu09, Mu10, Mu15, Mu23, Mu50, Mu51, and Mu59) conformed to Hardy–Weinberg equilibrium (HWE) expectations with only minor deviations, while the remaining two STR loci (Mu26 and G10B) were excluded from our set of putative forensic profiling system markers after revealing significant deviations from HWE in all four sub-populations. The average estimate of population substructure for Norwegian bears using 10 STRs (
F
ST) was determined to be 0.1, while the estimate for inbreeding (
F
IS) was −0.02. Accounting for the
F
ST-value, the average probability of identity (PI
ave) was 5.67
×
10
−10 and the average probability of sibling identity (PI
sib) was 1.68
×
10
−4. In Norway, this brown bear DNA profiling system has been applied to forensic casework.
In brown bears (Ursus arctos), nursing of young >1 year of age has a positive effect on their growth rate but is energetically costly for mothers and reduces the number of litters a female can ...produce during her lifetime. We followed radiomarked families to study their behavior during the period of family breakup. Yearlings separated from their mothers during the mating season and most family breakups were associated with the presence of an adult male, suggesting that termination of maternal care was not initiated by offspring.
GPS collars have greatly increased the number of locations obtained for individual animals during telemetry studies, but missed location attempts (missed fixes) may create bias in habitat analyses ...unless appropriately modeled. We placed GPS collars on captive grizzly bears (Ursus arctos) and observed their behavior while the collars attempted to obtain locations. Bear behavior influenced indices of GPS signal attenuation, the angle of the GPS antenna to the horizon, and collar height above the ground, but because bears sometimes rotate their collars, antenna angle varied within a behavior, particularly when collars fit snugly. We used a model selection approach to evaluate the influence of the angle of the GPS antenna to the horizon, collar height above the ground, and bear behavior on fix success. The model with both antenna angle and collar height was most parsimonious. We recommend fitting GPS collars such that the GPS antenna is opposite the battery pack (i.e., oriented up) for greatest fix success. Because collars sometimes rotate, sensors recording the antenna's angle to the horizon and bear height would help researchers model missed fixes related to signal attenuation caused by behavior. Although captive bear behavior may differ from wild bears, we provide a first look at the relative influences of antenna angle, antenna height, and bear behavior. When antenna angle and height information is not available, using activity sensors and bear movement rates to identify resting behavior should be considered to reduce bias in habitat analyses of GPS collar data.
Many temperate zone animals adapt to seasonal changes by altering their physiology. This is mediated in large part by endocrine signals that encode day length and regulate energy balance and ...metabolism. The objectives of this study were to determine if the daily patterns of two important hormones, melatonin and cortisol, varied with day length in captive brown bears (Ursus arctos) under anesthetized and nonanesthetized conditions during the active (March–October) and hibernation periods. Melatonin concentrations varied with time of day and season in nonanesthetized female bears despite exceedingly low nocturnal concentrations (1–4 pg/mL) in the active season. In contrast, melatonin concentrations during hibernation were 7.5‐fold greater than those during the summer in anesthetized male bears. Functional assessment of the pineal gland revealed a slight but significant reduction in melatonin following nocturnal light application during hibernation, but no response to beta‐adrenergic stimulation was detected in either season. Examination of pineal size in two bear species bears combined with a phylogenetically corrected analysis of pineal glands in 47 other species revealed a strong relationship to brain size. However, pineal gland size of both bear species deviated significantly from the expected pattern. Robust daily plasma cortisol rhythms were observed during the active season but not during hibernation. Cortisol was potently suppressed following injection with a synthetic glucocorticoid. The results suggest that melatonin and cortisol both retain their ability to reflect seasonal changes in day length in brown bears. The exceptionally small pineal gland in bears may be the result of direct or indirect selection.
e00048
Plasma melatonin in the brown bear varies with daylength but is present at exceedingly low concentrations. The pineal gland, a major source of melatonin, in the bear is significantly smaller, relative to brain size, than other mammals based on phylogenetic analysis. Cortisol concentrations also varied with daylength.
It is often difficult to determine optimal sampling design for non-invasive genetic sampling, especially when dealing with rare or elusive species depleted of genetic diversity. To address this ...problem, we ran a hair-snag pilot study on the remnant Apennine brown bear population. We used occupancy models to estimate the performance of an improved field protocol, a meta-analysis approach to indirectly model capture probability, and simulations to evaluate the effect of genotyping errors on the accuracy of capture-recapture population estimates. In spring 2007 we collected 70 bear hair samples in 15 5 × 5 km cells, using 5 10-day trapping sessions. Bear detectability was higher in 2007 than in a previous attempt on the same population in 2004, reflecting improved field protocols and sampling design. However, individual capture probability was 0.136 (95% CI = 0.120–0.152), still below the minimum requirements of capture-mark-recapture closed population models. We genotyped hair samples (
n
= 63) at 9 microsatellite loci, obtaining 94% Polymerase Chain Reaction success, and 13 bear genotypes. Estimated P
IDsib
was 0.00594, and per-genotype error rate was 0.13, corresponding to a 99% probability of correct individual identification. Simulation studies showed that the effect of non-corrected or filtered genetic errors on the accuracy of population estimates was negligible only when individual capture probability was >0.2. Our results underline how the interaction among field protocols, sampling strategies and genotyping errors may affect the accuracy of DNA-based estimates of small and genetically depleted populations, and warned us about the feasibility of a survey using only traditional hair-snag sampling. In this and similar cases, indications from pilot studies can provide cost-effective means to evaluate the efficiency of designed sampling and modelling procedures.
Although brown bears (
Ursus arctos
) are known to be major predators of ungulates in North America and Northern Europe, there is little documentation regarding bear predation on wild ungulates in ...Southern Europe. We describe search, detection, killing and prey consumption behaviour by brown bears during seven attacks on <1-month roe deer, red deer and chamois fawns in spring in the Cantabrian Mountains, north-western Spain. As soon as the bears detected a fawn by their smell or their mother's presence, they switched from routine foraging on plants and insects to an intensive search for the fawns, mainly using smell to comb a 0.5–1 ha area for 15–45 min. They killed the fawns either while the latter were resting or after a brief chase. The bears usually took their prey to dense vegetation, consuming it immediately. In four cases, 5-month-old cubs accompanying the female did not participate in the hunt. We also document the apparently non-predatory killing of a 40-kg wild boar by a female bear with cubs surprised by a sudden encounter. They did not eat the boar after the attack.
The objective of this study was to determine how the extender and dilution ratio used during centrifugation affect bear spermatozoa quality before and after freezing-thawing. Semen was collected from ...15 brown bears by electroejaculation. In experiment 1, semen was divided into five aliquots and diluted using one of the following extenders: Tris-citric-glucose (TCG), Tris-citric-glucose-3% BSA, Tris-citric-glucose-1% egg yolk or CaninePro. In experiment 2, semen was divided into five aliquots and diluted 1:1, 1:4, 1:8 or 1:16 (semen:extender) with Tris-citric-glucose. In both experiments, one aliquot was left undiluted and it was used as a control. All the aliquots were centrifuged at 600×g for 6 min and frozen. Samples were analysed by post-thawing for motility (CASA) and, by flow cytometry, for viability (YO-PRO-1), acrosomal status (PNA-FITC/PI) and mitochondrial status (JC-1). CaninePro rendered the highest motility with respect to the undiluted control (total motility, 53.1% vs. 38.5%, P < 0.001), and CaninePro and TCG significantly increased the percentage of viable and acrosome-intact spermatozoa (43.2 and 43.4, respectively, vs. 39.4, P < 0.05). In experiment 2, dilution 1:4 yielded the highest value of total motility (78.8 vs. 67.2, P < 0.05) and proportion of spermatozoa with intact membrane and acrosome (64.5 vs. 54.4, P < 0.01). In general, diluting 1:4 or 1:8 brown bear semen prior to centrifugation improved the motility and acrosome status of the thawed spermatozoa.
Sperm cryopreservation protocols for brown bear (Ursus arctos) require the centrifugation of semen samples to increase sperm concentration and to clean urine in contaminated samples. We evaluated the ...effect of centrifugation regimes (time and relative centrifugal force—RCF) on the quantity of sperm recovered and the quality of post-thawed sperm. Thirteen brown bears were electroejaculated. The ejaculates were diluted 1:1 in Tris–citric acid–glucose (TCG) extender and centrifuged with different RCF/time combinations: 600×g, 1,200×g and 2,400×g, for 3, 6 or 12 min. After centrifugation, spermatozoa were diluted in TES–Tris–fructose extender with egg yolk and glycerol (final glycerol concentration of 8%) and frozen in 0.25-mL straws. In the post-thawed semen, motility was assessed by CASA, and acrosomal status (PNA-FITC), viability (SYBR-14 with propidium iodide) and chromatin status (SCSA) were determined by flow cytometry. The longest centrifugation time (12 min) significantly decreased some motility parameters. Sperm recovery significantly decreased in brown bear at 600×g. Our results suggest that brown bear spermatozoa are more sensitive to long centrifugation times than to high RCF. Centrifugation regimes showed no effects on the post-thawing chromatin status. We recommend preparing the brown bear semen for freezing by centrifugation 1,200×g or 2,400×g for 6 min, after electroejaculation and dilution 1:1 in TCG extender, since these procedures increase the spermatozoa recovery without harmful effects on the post-thawed quality of brown bear spermatozoa.
Humeral chondrosarcoma was found in an 18-year-old male Hokkaido brown bear (Ursus arctos yesoensis). Necropsy revealed a large firm mass under the left superficial pectoral muscle at the axillary ...region. The mass involved the left shoulder joint and peripheral muscles, and connected to the head of the humerus with osteolysis. Histopathologically, the mass was composed of irregularly shaped myxomatous to cartilaginous tumor lobules. The tumor cell showed moderate nuclear atypia with a relatively high mitotic index, especially in the edges of the myxomatous lobules. The tumor cells were positively immunostained with vimentin and S-100 protein. Based on these findings, the tumors were diagnosed as chondrosarcoma. Metastases were found in the left axillary lymph node, lungs, liver and kidney.
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