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

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.

2013 ◽  
Vol 127 (2) ◽  
pp. 118 ◽  
Author(s):  
Derrick A. Romain ◽  
Martyn E. Obbard ◽  
James L. Atkinson

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.


Animals ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 1123
Author(s):  
Lynn L. Rogers ◽  
Linda McColley ◽  
Janet Dalton ◽  
Jim Stroner ◽  
Douglas Hajicek ◽  
...  

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.


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

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.


1988 ◽  
Vol 66 (10) ◽  
pp. 2095-2103 ◽  
Author(s):  
Robert K. Maxwell ◽  
Jeffrey Thorkelson ◽  
Lynn L. Rogers ◽  
Robert B. Brander

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.


1992 ◽  
Vol 37 (4) ◽  
pp. 433 ◽  
Author(s):  
Susan F. McClinton ◽  
Philip L. McClinton ◽  
Jim V. Richerson

2021 ◽  
pp. 721-728
Author(s):  
A.A.D. McLaren ◽  
S.E. Jamieson ◽  
M. Bond ◽  
A.R. Rodgers ◽  
B.R. Patterson

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.


1983 ◽  
Vol 5 ◽  
pp. 1 ◽  
Author(s):  
David M. Graber ◽  
Marshall White

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