scholarly journals Development of a noninvasive photograph-based method for the evaluation of body condition in free-ranging brown bears

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e9982
Author(s):  
Yuri Shirane ◽  
Fumihiko Mori ◽  
Masami Yamanaka ◽  
Masanao Nakanishi ◽  
Tsuyoshi Ishinazaka ◽  
...  
Keyword(s):  
Body Condition ◽  
Seasonal Changes ◽  
Ursus Arctos ◽  
Accurate Method ◽  
Condition Index ◽  
The Body ◽  
Length Ratio ◽  
Brown Bears ◽  
Practical Applications ◽  
Free Ranging

Body condition is an important determinant of health, and its evaluation has practical applications for the conservation and management of mammals. We developed a noninvasive method that uses photographs to assess the body condition of free-ranging brown bears (Ursus arctos) in the Shiretoko Peninsula, Hokkaido, Japan. First, we weighed and measured 476 bears captured during 1998–2017 and calculated their body condition index (BCI) based on residuals from the regression of body mass against body length. BCI showed seasonal changes and was lower in spring and summer than in autumn. The torso height:body length ratio was strongly correlated with BCI, which suggests that it can be used as an indicator of body condition. Second, we examined the precision of photograph-based measurements using an identifiable bear in the Rusha area, a special wildlife protection area on the peninsula. A total of 220 lateral photographs of this bear were taken September 24–26, 2017, and classified according to bear posture. The torso height:body/torso length ratio was calculated with four measurement methods and compared among bear postures in the photographs. The results showed torso height:horizontal torso length (TH:HTL) to be the indicator that could be applied to photographs of the most diverse postures, and its coefficient of variation for measurements was <5%. In addition, when analyzing photographs of this bear taken from June to October during 2016–2018, TH:HTL was significantly higher in autumn than in spring/summer, which indicates that this ratio reflects seasonal changes in body condition in wild bears. Third, we calculated BCI from actual measurements of seven females captured in the Rusha area and TH:HTL from photographs of the same individuals. We found a significant positive relationship between TH:HTL and BCI, which suggests that the body condition of brown bears can be estimated with high accuracy based on photographs. Our simple and accurate method is useful for monitoring bear body condition repeatedly over the years and contributes to further investigation of the relationships among body condition, food habits, and reproductive success.

Sexing free-ranging brown bears Ursus arctos using hairs found in the field

1993 ◽  
Vol 2 (6) ◽  
pp. 399-403 ◽  
Author(s):  
P. TABERLET ◽  
H. MATTOCK ◽  
C. DUBOIS-PAGANON ◽  
J. BOUVET
Keyword(s):  
Ursus Arctos ◽  
Brown Bears ◽  
Free Ranging

scholarly journals Rodent helminths in fragmented Atlantic Forest areas in the western region of the state of Paraná

2021 ◽  
Vol 30 (3) ◽  
Author(s):  
Danise Benatti ◽  
Luis Felipe Andrietti ◽  
José Flávio Cândido Júnior ◽  
Alexandre Vogliotti ◽  
Marcela Figueirêdo Duarte Moraes ◽  
...  
Keyword(s):  
Atlantic Forest ◽  
Body Condition ◽  
Condition Index ◽  
Ecological Indicators ◽  
The Body ◽  
Western Region ◽  
Body Condition Index ◽  
Intensity Of Infection ◽  
New Host ◽  
The Western Region

Abstract Rodents are small mammals that can be parasitized by various helminths. This study aimed to identify and describe the ecological indicators of infection in rodents captured in fragments of the Atlantic Forest in the western region of Paraná State, Brazil. Sixty-eight specimens of five rodent species were collected, necropsied, and inspected in search of helminths. The parasites were stored in 70% ethanol, morphologically identified, and counted for calculation of infection indicators. Fourteen species of helminths and one species of Crustacea were recorded: ten in Akodon montensis, four in Mus musculus, two in Thaptomys nigrita, two in Oligoryzomys nigripes, and one in Euryoryzomys russatus. The registered species of parasites were: Rodentolepis akodontis, Angiostrongylus sp., Protospirura numidica criceticola, Trichuris navonae, Syphacia alata, Syphacia criceti, Syphacia evaginata, Trichofreitasia lenti, Stilestrongylus aculeata, Stilestrongylus eta, Stilestrongylus gracielae, Stilestrongylus franciscanus, Stilestrongylus moreli, Stilestrongylus sp., and Pentastomida gen. sp. A positive correlation between the intensity of infection of T. navonae and T. lenti was observed with the body condition index of the host A. montensis. For all species, this study represents a new register of locality, and for eight of them a new host.

scholarly journals Specific shifts in the endocannabinoid system in hibernating brown bears

2020 ◽  
Author(s):  
Christian Boyer ◽  
Laura Cussonneau ◽  
Charlotte Brun ◽  
Christiane Deval ◽  
Jean-Paul Pais de Barros ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Ursus Arctos ◽  
Mild Hypothermia ◽  
Endocannabinoid System ◽  
Fold Increase ◽  
Physiological Adaptation ◽  
Acid Oxidation ◽  
Brown Bears ◽  
Peripheral Tissues ◽  
Free Ranging

Abstract In small hibernators, global downregulation of the endocannabinoid system (ECS), which is involved in modulating neuronal signaling, feeding behavior, energy metabolism, and circannual rhythms, has been reported to possibly drive physiological adaptation to the hibernating state. We hypothesized that specific changes should occur in hibernating brown bears ( Ursus arctos ) due to specific features, including hibernation during half the year at only mild hypothermia while remaining physically inactive without drinking or eating, and the absence of arousal episodes although bears remain sensitive to external disturbances. We explored circulating lipids and the ECS in plasma and metabolically active tissues (muscle and adipose tissue), in free-ranging subadult Scandinavian brown bears when both active and hibernating. In winter bear serum, in addition to a 2-fold increase in total fatty acid concentration, we found significant changes in relative proportions of circulating fatty acids, such as a 2-fold increase in docosahexaenoic acid and a decrease in arachidonic acid. In adipose and muscle tissues of hibernating bears, we found lower concentrations of both two major ligands for endocannabinoid receptors, 2-arachidonoylglycerol (2-AG) and anandamide (AEA). Gene expression was reduced for enzymes that synthesize endocannabinoid compounds, whereas an increase was observed for catabolic enzymes. Reduction in ECS tone may promote mobilization of fat stores and favor carbohydrate metabolism in skeletal muscle of hibernating bears. Additionally, high circulating of the endocannabinoid-like compound N-oleoylethanolamide (OEA) in winter could favor lipolysis and fatty acid oxidation in peripheral tissues. We also speculated on a role of OEA in the maintenance of torpor (reduction in locomotion), while promoting the capacity of bears to sense stimuli from the environment.

scholarly journals Genetic variation and natural selection on blue tit body condition in different environments

1999 ◽  
Vol 73 (2) ◽  
pp. 165-176 ◽  
Author(s):  
J. MERILÄ ◽  
R. PRZYBYLO ◽  
B. C. SHELDON
Keyword(s):  
Natural Selection ◽  
Body Condition ◽  
Genetic Variance ◽  
Condition Index ◽  
The Body ◽  
Phenotypic Variance ◽  
Body Condition Index ◽  
Blue Tit ◽  
Feeding Regime ◽  
The Poor

An increasing amount of evidence indicates that different forms of environmental stress influence the expression of genetic variance in quantitative traits and, consequently, their evolvability. We investigated the causal components of phenotypic variance and natural selection on the body condition index (a trait often related to fitness in wild bird populations) of blue tit (Parus caeruleus) nestlings under contrasting environmental conditions. In three different study years, nestlings grown under a poor feeding regime attained lower body condition than their full-sibs grown under a good feeding regime. Genetic influences on condition were large and significant in both feeding regimes, and in all three study years. However, although estimates of additive genetic variance were consistently higher in the poor than in the good environment, heritability estimates for body condition index were very similar in both environments due to higher levels of environmental variance in the poor environment. Evidence for weak genotype×environment interactions was obtained, but these contributed little to variance in nestling condition. Directional natural selection on fledging condition of nestlings was detected, and there were no indications of year or environmental effects on the form and intensity of selection observed, in a sample of 3659 nestlings over four years. However, selection on fledging condition was very weak (standardized selection gradient, β=0·027±0·016 SE), suggesting that, in the current population, the large additive genetic component to fledging condition is not particularly surprising. The results of these analyses are contrasted with those obtained for other populations and species with similar life-histories.

scholarly journals Mortality Causes in Free-Ranging Eurasian Brown Bears (Ursus arctos arctos) in Spain 1998–2018

Animals ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1538
Author(s):  
Ana Balseiro ◽  
Luis J. Royo ◽  
Elena Gayo ◽  
Ramón Balsera ◽  
Olga Alarcia ◽  
...  
Keyword(s):  
Infectious Diseases ◽  
Ursus Arctos ◽  
Mushroom Poisoning ◽  
Mountain Range ◽  
Human Intervention ◽  
Brown Bears ◽  
Cantabrian Mountain ◽  
Traumatic Lesions ◽  
Free Ranging ◽  
Infectious Etiology

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.

Selective predation by brown bears (Ursus arctos) foraging on spawning sockeye salmon (Oncorhynchus nerka)

2000 ◽  
Vol 78 (6) ◽  
pp. 974-981 ◽  
Author(s):  
Gregory T Ruggerone ◽  
Renn Hanson ◽  
Donald E Rogers
Keyword(s):  
Sockeye Salmon ◽  
Ursus Arctos ◽  
Oncorhynchus Nerka ◽  
The Body ◽  
Upstream Migration ◽  
Selective Predation ◽  
Bristol Bay ◽  
Brown Bears ◽  
Risk Of Predation ◽  
Salmon Population

Selective predation by and predation rates of brown bears (Ursus arctos) foraging on spawning sockeye salmon (Oncorhynchus nerka) in a small shallow creek in the Wood River lake system near Bristol Bay, Alaska, were quantified during 1986 and 1990–1992. Bears killed a high proportion of spawning salmon when few salmon entered the creek (92% of 505 fish) and a much smaller proportion when the spawning population reached a historical high (16% of 15 631 fish). Selective predation on salmon that differed in length, sex, and spawning condition was measured by tagging salmon at the mouth of the creek immediately prior to upstream migration and then recovering dead tagged fish during daily surveys of the entire creek. The relative frequencies of large, medium-sized, and small salmon killed by bears indicated that the risk of predation was more than 150% greater for large than for small salmon. A higher proportion of the male salmon population was killed and a greater proportion of male bodies were consumed than female salmon. Selectivity for male salmon increased as the spawning season progressed, possibly because male salmon weakened earlier and lived longer in a weakened state than female salmon. Male salmon were attacked mostly along the dorsal hump area, whereas female salmon tended to be attacked along the abdomen, where eggs could be exposed. Bears selectively killed female salmon prior to spawning during 1 of the 3 years, but only 6.1–7.8% of the female spawning populations were killed prior to spawning. These data support the hypothesis that selective predation by bears may influence the body morphology of spawning salmon.

scholarly journals Haematological and biochemical reference intervals for free-ranging brown bears (Ursus arctos) in Sweden

2014 ◽  
Vol 10 (1) ◽  
Author(s):  
Anne Randi Græsli ◽  
Åsa Fahlman ◽  
Alina L Evans ◽  
Mads Frost Bertelsen ◽  
Jon Martin Arnemo ◽  
...  
Keyword(s):  
Ursus Arctos ◽  
Reference Intervals ◽  
Brown Bears ◽  
Free Ranging

scholarly journals Room without a view – den construction in relation to body size in brown bears

2019 ◽  
Author(s):  
Shotaro Shiratsuru ◽  
Andrea Friebe ◽  
Jon E. Swenson ◽  
Andreas Zedrosser
Keyword(s):  
Body Size ◽  
Energy Conservation ◽  
Physical Properties ◽  
Heat Loss ◽  
Body Condition ◽  
Ursus Arctos ◽  
Abiotic Factors ◽  
Adaptive Strategy ◽  
Brown Bears ◽  
The Impact

AbstractHibernation is an adaptive strategy to survive harsh winter conditions and food shortage. The use of well-insulated winter dens helps animals minimize energy loss during hibernation. Brown bears (Ursus arctos) commonly use excavated dens for hibernation. Physical properties of excavated dens, such as the amount of space between a bear and the inner wall, wall/roof thickness, and bedding materials, are expected to impact heat retention and energy conservation of bears. The objective of this study was to examine the impact of physical properties of excavated dens on energy conservation in hibernating bears. Our hypothesis was that bears excavate dens in a way to minimize heat loss and optimize energy conservation during hibernation. We predicted that physical properties of excavated dens would significantly affect the bears’ post-hibernation body condition. To test our hypothesis and prediction, we analyzed data collected from brown bears in Sweden with linear mixed effects models, examining (i) what factors affect den-excavation behavior and (ii) if physical properties of excavated dens affect post-hibernation body condition. We found that bears excavated a den cavity in relation to their body size, that older bears tended to excavate better-fitting den cavities compared to young bears, and that the physical properties of excavated dens did not significantly affect a bears’ post-hibernation body condition. Older bears excavated better-fitting den cavities, suggesting a potentially experience-based shift with age in den-excavation behavior and an optimum cavity size relative to a bear’s body size. The strong year effect shown by the most parsimonious model for post-hibernation body condition suggests that variations in physical properties of excavated dens are possibly negligible, compared to the large annual variations in biotic and abiotic factors affecting pre-hibernation body condition and heat loss during hibernation.

scholarly journals Mortality in free-ranging Eurasian brown bears (Ursus arctos arctos) in Spain (1998-2018)

2020 ◽  
Author(s):  
Ana Balseiro ◽  
Luis José Royo ◽  
Elena Gayo ◽  
Ramón Balsera ◽  
Olga Alarcia ◽  
...  
Keyword(s):  
Infectious Diseases ◽  
Cause Of Death ◽  
Causes Of Death ◽  
Ursus Arctos ◽  
Mushroom Poisoning ◽  
Human Intervention ◽  
Pathological Findings ◽  
Brown Bears ◽  
Traumatic Lesions ◽  
Free Ranging

Abstract Background This work summarizes the confirmed causes of death of twenty-five free-ranging Eurasian 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. Results Causes of death were classified based on (i) pathological findings and (ii) caused by “human intervention” or “non human intervention”. In four cases (16%) it was not possible to determine the cause of death due to the bad preservation of found remains or insufficient tissue availability. Based on pathological findings seven out of the 21 (33.3%) brown bears in which the cause of death could be determined died due to infectious diseases (clostridiosis n =4 or infectious canine hepatitis n =3), two (9.5%) due to exertional (degenerative) myopathy (one of those bears also showed clostridiosis) and one due to strychnine poisoning (4.8%), neoplasia (4.8%) or mushroom poisoning (4.8%). The remaining animals died due to traumatic lesions (including fights or infanticide), shooting or wire snare. Mortality data was also classified by deaths caused by “human intervention” or “non human intervention”. The death of one bear showing exertional myopathy after handling was not ascribed to any of the former classifications. Six out of the 20 (30%) brown bears died as a consequence of “human intervention” due to illegal hunting (wire snare hunting n =3 or shooting n =2) and, strychnine poisoning ( n =1). In contrast, fourteen (14/20, 70%) brown bears died by “non-human intervention”; nine of them (9/20, 45%) due to traumatic lesions (fights n =4, traumas n =3 or infanticide n =2), three (3/20, 15%) due to infectious canine hepatitis caused by canine adenovirus type 1 (CAdV-1) infection, one (1/20, 5%) due to cholangiocarcinoma and another one (5%) due to mushroom poisoning. Conclusions This study shows that the main causes of death in Eurasian brown bears are those caused by infectious diseases. In contrast to previous data on free-ranging bears for the first time infectious diseases appear as an important cause of death. These data are valuable and may help in the conservation and management of this recovering population.

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