Seasonal serum glucose, progesterone, and Cortisol levels of black bears (Ursus americanus)

1990 ◽  
Vol 68 (1) ◽  
pp. 183-187 ◽  
Author(s):  
Henry J. Harlow ◽  
Thomas D. I. Beck ◽  
Lisa M. Walters ◽  
Shelley S. Greenhouse
Keyword(s):  
Ursus Americanus ◽  
Black Bear ◽  
Serum Cortisol ◽  
Serum Glucose ◽  
Black Bears ◽  
Stress Exposure ◽  
Summer Period ◽  
Serum Progesterone ◽  
Fat Reserves ◽  
Different Seasons

Sixty-two black bears were captured at different seasons during the years 1983–1987. Bears were anesthetized in their dens during the winter and parts of the fall and spring, while bears captured during the summer were snared prior to anesthesia. Radioimmunoassays for both Cortisol and progesterone were validated on black bear serum. An improved, rapid progesterone radioimmunoassay for black bear serum is reported. Serum glucose demonstrated a tendency for reduction during spring. Serum progesterone levels did not demonstrate seasonal differences and were significantly higher in females only during the summer ovulatory/postestrus period. Serum Cortisol was significantly elevated during the winter denning period as compared with the summer period. We conclude that differences in serum progesterone, Cortisol, and glucose may not be indicators of stress exposure, but of seasonal reproductive states and metabolic utilization of fat reserves.

scholarly journals Behavior in Free-Living American Black Bear Dens: Parturition, Maternal Care, and Cub Behavior

Animals ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 1123
Author(s):  
Lynn L. Rogers ◽  
Linda McColley ◽  
Janet Dalton ◽  
Jim Stroner ◽  
Douglas Hajicek ◽  
...  
Keyword(s):  
Ursus Americanus ◽  
Post Partum ◽  
Black Bear ◽  
Geographic Region ◽  
Black Bears ◽  
Free Living ◽  
Future Studies ◽  
American Black Bear ◽  
Eye Opening ◽  
American Black

Denning behavior has long remained the least observed aspect of bear behavior. During 2010–2013, we used webcams, microphones, the internet, and 14,602 h of archived video to document the denning behaviors of two adult wild black bears (Ursus americanus) as they gave birth and cared for four litters through six winters in northeastern Minnesota. Observations included types of dens, labor, pre-parturient genital swelling, birthing positions, post-partum vocalizations, mothers removing amniotic tissues and warming newborn cubs in sub-freezing temperatures, frequency of nursing, cubs establishing nipple order, yearlings suckling, the ingestion of snow and icicles, the ingestion of foot pads, urination and defecation in latrine areas, toilet-licking, eye opening, reciprocal tongue-licking, play, rapid eye movement (REM) sleep and possible dreaming, and reactions to wildlife intruders. The use of this new method for observing natural bear dens allowed the identification of many behaviors undescribed for any species of wild bear in dens. We also discuss the need for future studies and how the depth and duration of black bear hibernation varies with body condition and geographic region.

scholarly journals Heart rate during hyperphagia differs between two bear species

2019 ◽  
Vol 15 (1) ◽  
pp. 20180681 ◽  
Author(s):  
Boris Fuchs ◽  
Koji Yamazaki ◽  
Alina L. Evans ◽  
Toshio Tsubota ◽  
Shinsuke Koike ◽  
...  
Keyword(s):  
Heart Rate ◽  
Ursus Arctos ◽  
Brown Bear ◽  
Black Bear ◽  
Black Bears ◽  
Brown Bears ◽  
Fat Reserves ◽  
Generalized Additive Mixed Models ◽  
Additive Mixed Models ◽  
Increased Activity

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.

A study of predominant aerobic microflora of black bears (Ursus americanus) and grizzly bears (Ursus arctos) in northwestern Alberta

1987 ◽  
Vol 33 (11) ◽  
pp. 949-954 ◽  
Author(s):  
L. J. Goatcher ◽  
M. W. Barrett ◽  
R. N. Coleman ◽  
A. W. L. Hawley ◽  
A. A. Qureshi
Keyword(s):  
Soil Bacteria ◽  
Ursus Arctos ◽  
Random Distribution ◽  
Ursus Americanus ◽  
Black Bear ◽  
Black Bears ◽  
Grizzly Bears ◽  
Grizzly Bear ◽  
Streptococcus Species ◽  
Generic Composition

Swab specimens were obtained from nasal, rectal, and preputial or vaginal areas of 37 grizzly and 17 black bears, captured during May to June of 1981 to 1983, to determine the types and frequency of predominant aerobic microflora. Bacterial genera most frequently isolated from bears were Escherichia, Citrobacter, Hafnia, Proteus, Staphylococcus, and Streptococcus species, comprising about 65% of the isolates. Erwinia, Xanthomonas, Agrobacterium, Rhizobium, and Gluconobacter/Acetobacter were also isolated but at lower frequencies (< 5%). Comparison of bacterial generic composition using similarity quotient values showed no appreciable differences between grizzly and black bear flora. Also, no outstanding differences in bacterial generic composition were observed among grizzly bear samples; however, differences were noted among black bear samples. Fungal genera most commonly encountered included Cryptococcus, Rhodotorula, Cladosporium, Penicillium, Sporobolomyces, and Candida. In general, the microflora of both bear types were marked by generic diversity and random distribution. The majority of microorganisms isolated from the plant samples in the study area were also found in bear samples. This observation and the presence of certain water and soil bacteria in samples from bears suggest that the predominant microflora of both grizzly and black bears were transient and probably influenced by their foraging habits and surrounding environments.

The field energetics of winter-dormant black bear (Ursus americanus) in northeastern Minnesota

1988 ◽  
Vol 66 (10) ◽  
pp. 2095-2103 ◽  
Author(s):  
Robert K. Maxwell ◽  
Jeffrey Thorkelson ◽  
Lynn L. Rogers ◽  
Robert B. Brander
Keyword(s):  
Mass Loss ◽  
Ursus Americanus ◽  
Heat Budget ◽  
Energy Requirement ◽  
Black Bear ◽  
Oblate Spheroid ◽  
Black Bears ◽  
Protein Catabolism ◽  
Winter Climate ◽  
Internal Sources

Black bears (Ursus americanus) can spend half of their lives in a severe winter climate using only internal sources of energy and exchanging energy only as heat with their external environment. This paper presents the energy requirement to maintain a bear, and the magnitude of the heat transfer pathways to the bear's surroundings. Flux rate densities of the heat budget were measured for two denning black bears. It was found that the surface area of an oblate spheroid simulating the shape of the curled-up bears balanced the budgets. From these data a simulated bear–den system was constructed for a 75-kg animal: a fur-covered spheroid that was electrically heated and maintained at 36 °C. The energy requirement and heat transport were measured through the skin and in the den over winter, as was the oxygen consumption of a live bear in a similar den nearby. Over a 145-day denning period, mass loss due to fat catabolism would have ranged between 24 and 28% for the simulated bear with the entrance sealed or open, respectively. Using the amount of oxygen consumed and holding body water constant, the mass loss of the live bear over the same period would have been 19% if just fat had been catabolized. However, additional protein catabolism near the end of the denning period caused the loss to increase to 31%, primarily through urination. Once net protein catabolism began, dehydration and not starvation became life threatening.

Food habits and nutrition of black bears during a gypsy moth infestation

1995 ◽  
Vol 73 (9) ◽  
pp. 1771-1775 ◽  
Author(s):  
John W. Kasbohm ◽  
James G. Kraus ◽  
Michael R. Vaughan
Keyword(s):  
Gypsy Moth ◽  
Food Habits ◽  
National Park ◽  
Crude Protein ◽  
Ursus Americanus ◽  
Substantial Reduction ◽  
Black Bear ◽  
Black Bears ◽  
Phytolacca Americana ◽  
Shenandoah National Park

During 1988–1991 we determined food habits and indices of diet quality for a black bear (Ursus americanus) population in Shenandoah National Park, Virginia, experiencing a severe gypsy moth (Lymantria dispar) defoliation event, and compared the results with data collected prior to defoliation (1982–1984). Gypsy moth infestation resulted in extensive summer overstory canopy loss and a complete acorn failure in affected areas. As in predefoliation years, analysis of scats collected during defoliation indicated that bears ate primarily herbaceous vegetation in spring, followed by squawroot (Canopholis americana) and fruits of black and sweet cherry (Prunus serotina and P. avium) in summer. However, in early and late fall bears switched from consuming predominantly acorns before defoliation to pokeweed (Phytolacca americana) berries and grapes (Vitis spp.), respectively, during defoliation. Despite acorn loss, no decline in dietary nutritional quality was observed in comparisons of the percentages of crude protein, crude fat, and crude fiber in seasonal diets before and during defoliation. When it is available, bears can successfully exploit soft mast as a fall food source and do not necessarily experience a substantial reduction in food quality if acorn crops fail.

Spring diet of American black bears (Ursus americanus) in a moose (Alces alces) – woodland caribou (Rangifer tarandus caribou) system in northern Ontario, Canada

2021 ◽  
pp. 721-728
Author(s):  
A.A.D. McLaren ◽  
S.E. Jamieson ◽  
M. Bond ◽  
A.R. Rodgers ◽  
B.R. Patterson
Keyword(s):  
Rangifer Tarandus ◽  
Ursus Americanus ◽  
Alces Alces ◽  
Black Bear ◽  
Black Bears ◽  
Rangifer Tarandus Caribou ◽  
Woodland Caribou ◽  
Northern Ontario ◽  
American Black ◽  
American Black Bears

American black bears (Ursus americanus Pallas, 1780) are opportunistic foragers, and across most of their range in North America, their diet is predominantly vegetation with limited consumption of vertebrates and invertebrates. However, they are also predators of ungulates, especially neonates, with regional variation in the amount of predation pressure they exert. We used scat analysis to examine the diet of black bears during the calving season in a moose (Alces alces (Linnaeus, 1758)) – woodland caribou (Rangifer tarandus caribou (Gmelin, 1788)) system in the Boreal forest of northern Ontario, Canada. Bears consumed herbaceous plants (46.5%), fruits and (or) seeds (20.0%), moose (3.3% adults; 4.3% calves), American beaver (Castor canadensis Kuhl, 1820; 8.5%), and insects (mostly ants; 4.2%). Bears had the highest consumption of moose and beaver in early spring, before switching to a more vegetation-dominated diet. We did not detect evidence of caribou consumption. Based on our results, black bear consumption of moose, particularly neonates, may warrant further investigation.

scholarly journals Temporal variation in food habits of the American Black Bear (Ursus americanus) in the boreal forest of northern Ontario

2013 ◽  
Vol 127 (2) ◽  
pp. 118 ◽  
Author(s):  
Derrick A. Romain ◽  
Martyn E. Obbard ◽  
James L. Atkinson
Keyword(s):  
Temporal Variation ◽  
Food Habits ◽  
Ursus Americanus ◽  
Late Summer ◽  
Black Bear ◽  
Black Bears ◽  
Northern Ontario ◽  
American Black Bear ◽  
American Black ◽  
American Black Bears

We used scat analysis to investigate temporal variation in the food habits of American Black Bears (Ursus americanus) in the boreal forest of northern Ontario. Specifically, we examined whether there was a seasonal shift in foraging over three years (1990–1992) and which foods, if any, varied in occurrence among years. American Black Bears ate foods ranging from green vegetation in the spring to ants in mid-summer and berries and nuts in late summer and fall. Late summer berry forage, especially blueberries (Vaccinium spp.), varied greatly among years. American Black Bears in northern Ontario consumed a variety of foods opportunistically. Understanding how American Black Bears in northern Ontario exploit food resources and how these food items vary among years can provide insights into demographic processes and help wildlife managers better anticipate changes in the structure of the harvest of American Black Bears and in human–bear conflict levels. In northern Ontario, forest management practices that increase the availability of early successional species would be beneficial to American Black Bear populations.

Serum progesterone, oestradiol, luteinizing hormone and prolactin profiles in the female black bear (Ursus americanus)

1998 ◽  
Vol 53 (1-4) ◽  
pp. 107-118 ◽  
Author(s):  
T Tsubota ◽  
L Howell-Skalla ◽  
W.R Boone ◽  
D.L Garshelis ◽  
J.M Bahr
Keyword(s):  
Luteinizing Hormone ◽  
Ursus Americanus ◽  
Black Bear ◽  
Serum Progesterone

Dynamics of woodland caribou populations at the southern limit of their range in Saskatchewan

1998 ◽  
Vol 76 (2) ◽  
pp. 251-259 ◽  
Author(s):  
W James Rettie ◽  
François Messier
Keyword(s):  
Rangifer Tarandus ◽  
Ursus Americanus ◽  
Road Construction ◽  
Black Bear ◽  
Woodland Caribou ◽  
Serum Progesterone ◽  
Southern Limit ◽  
Disjunct Populations ◽  
Calf Survival ◽  
Proximate Causes

Woodland caribou (Rangifer tarandus caribou) in central Saskatchewan are aggregated into several spatially disjunct populations. Historical data indicate that some local populations were eliminated and that the regional metapopulation declined during the 1970s. Proximate causes of decline may have included hunting, severe winter weather, and the end of predator control, though the ultimate causes may relate to road construction and logging activity, which expanded after 1966. There has been no sport hunting since 1987, yet the caribou populations in the region appear to be declining. Based on serum progesterone levels, first conception by females occurred at 16 months and the overall pregnancy rate was 94%, and in addition the minimum parturition rate was 86%, all of which indicate adequate nutrition. The annual survival rate of adults was 84%, which is comparatively low, though similar to results from other studies on woodland caribou. We observed a low rate of calf recruitment (28 calves : 100 cows), which we suspect was due to predation. Wolves (Canis lupus) have long been thought to limit woodland caribou populations while subsisting on other ungulate prey, but we speculate that black bear (Ursus americanus) predation may be an important cause of poor calf survival.

Crenosoma spp. (Nematoda: Metastrongyloidea) from black bears, Ursus americanus, of central Ontario

1978 ◽  
Vol 56 (9) ◽  
pp. 1993-1997 ◽  
Author(s):  
Edward M. Addison
Keyword(s):  
Ursus Americanus ◽  
Black Bear ◽  
Black Bears ◽  
Crenosoma Vulpis ◽  
First Time ◽  
The Relationship

Crenosoma vulpis (Dujardin 1844) Railliet 1915, Crenosoma petrowi Morozov 1939, and Crenosoma potos Buckley 1930 are redescribed from the lungs of black bear, Ursus americanus, of central Ontario. A telamon is described in each species for the first time. The relationship between C. petrowi and Crenosoma schulzi Gagarin 1958 is discussed.

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