The significance of supplemental food to polar bears during the ice-free period of Hudson Bay

1985 ◽  
Vol 63 (10) ◽  
pp. 2291-2297 ◽  
Author(s):  
N. J. Lunn ◽  
Ian Stirling
Keyword(s):  
Food Sources ◽  
Hudson Bay ◽  
Polar Bears ◽  
Adult Males ◽  
Blood Samples ◽  
Supplemental Food ◽  
Pregnant Females ◽  
Major Factors ◽  
Age And Sex ◽  
Family Groups

Polar bears were studied near Churchill, Manitoba, to evaluate the possible importance of supplemental food. Once ashore, bears became segregated by age and sex; family groups and pregnant females moved inland into a denning area, while single bears, especially adult males, remained along the coast. Bears were inactive and fed little. Analysis of blood samples taken from bears in the denning area suggested that they also were not feeding. By remaining inactive, they are able to minimize energetic demands and the chance of hyperthermia. After 2 months ashore, some bears, mainly family groups and subadults, fed in the Churchill dump. The data indicated that individual needs and learning were major factors determining which bears used the dump. Adult males did not feed there even though they may have been there previously as cubs or subadults. Bears which fed in the dump were significantly heavier than those which did not. There was no evidence that bears using the dump gained either reproductive or survival advantages. We conclude that polar bears will use supplemental food sources which are available or if they have previously learned their location; however, it is not necessary for their survival.

Distribution of polar bears (Ursus maritimus) during the ice-free period in western Hudson Bay

1990 ◽  
Vol 68 (7) ◽  
pp. 1395-1403 ◽  
Author(s):  
Andrew E. Derocher ◽  
Ian Stirling
Keyword(s):  
Energy Conservation ◽  
Sea Ice ◽  
Ursus Maritimus ◽  
North Coast ◽  
Hudson Bay ◽  
Polar Bears ◽  
Adult Males ◽  
The North ◽  
Western Hudson Bay ◽  
Age And Sex

The distribution and movements of polar bears (Ursus maritimus) during the ice-free period in western Hudson Bay were studied using mark and recapture and radiotelemetry locating of animals of known age and sex collected between 1966 and 1987. Polar bears segregated themselves by age, sex, and reproductive status. Adult males occupied coastal areas. Family groups and pregnant females occupied areas farther inland. Subadult females and males occupied similar habitats which overlapped with those of adult males. Avoidance of conspecifics, energy conservation, philopatry, denning habitat, and habitat selection appeared to influence observed patterns. A southward shift in the population was evident early in the ice-free period and was followed by a return movement northward during October and November. This may be due to ice-formation patterns which permit earlier access to the sea ice along the north coast and hunting habitat to the northeast. All bears moved less than bears on the sea ice, and movements were consistent with a strategy of energy conservation. Most bears appear to have travelled directly from the sea ice to the study area and remained until the sea ice reformed. Little exchange with adjacent populations and a high degree of philopatry were evident for all age and sex groups; this may be a function of the distribution of denning habitat, the winter distribution of sea ice habitat and seals, and the noncompetitive conditions that prevail during the ice-free period which make dispersal of limited benefit.

Spatial relationships and behavior of polar bears (Ursus maritimus Phipps) concentrated on land during the ice-free season of Hudson Bay

1981 ◽  
Vol 59 (9) ◽  
pp. 1763-1774 ◽  
Author(s):  
Paul B. Latour
Keyword(s):  
Social Behavior ◽  
Sea Ice ◽  
Social Systems ◽  
Ursus Maritimus ◽  
Hudson Bay ◽  
Polar Bears ◽  
Adult Males ◽  
Single Population ◽  
A Site ◽  
And Behavior

I observed polar bears (Ursus maritimus Phipps) at Cape Churchill, Manitoba, a site where polar bears congregate during the autumn when Hudson Bay is ice free. Adult males, subadult males, and subadult females were spatially segregated to a degree that depended primarily on density. The higher the density, the greater the degree of segregation. Adult males showed the closest intraclass association. Subadult females spent more time in activity than did either adult or subadult males; this may be due to subadult females being approached more by other subadults. Much of an individual's social behavior occurred with members of its own age–sex class, perhaps as a result of spatial segregation. In the noncompetitive situation of this study, polar bears aggregated and were more social than when hunting on the sea ice. This study provides further evidence for the flexibility of carnivore social systems, not only between populations of the same species, but also within a single population.

Observations of aggregating behaviour in adult male polar bears (Ursus maritimus)

1990 ◽  
Vol 68 (7) ◽  
pp. 1390-1394 ◽  
Author(s):  
Andrew E. Derocher ◽  
Ian Stirling
Keyword(s):  
Adult Male ◽  
Ursus Maritimus ◽  
Hudson Bay ◽  
Polar Bears ◽  
Adult Males ◽  
Mean Size ◽  
The Mean ◽  
Competition For Food ◽  
Competition For Resources ◽  
Solitary Species

Polar bears (Ursus maritimus) are usually considered a solitary species, but between 50 and 60% of the adult male polar bears captured on land during the ice-free period in western Hudson Bay were sighted in aggregations with a mean size of 4 and a range of 2–14 individuals. The mean weight of aggregating adult males was significantly greater (approximately 60 kg) than the mean weight of nonaggregating adult males, but there were no significant differences in the mean age. Aggregations occurred throughout the ice-free period (August–October) and were most common at prominent points along the coast or nearby islands. Some locations were used over several years. The lack of competition for food and the absence of breeding activity during the ice-free period produce conditions that may facilitate aggregating. Familiarity with conspecifics may yield benefits by reducing the severity and frequency of competition for resources on the sea ice.

Speed of Action in Cockroach Bait, 1993

1994 ◽  
Vol 19 (1) ◽  
pp. 361-361
Author(s):  
Walid Kaakeh ◽  
B. L. Reid ◽  
G. W. Bennett
Keyword(s):  
Random Order ◽  
Probit Analysis ◽  
Food Sources ◽  
Ratio Test ◽  
Adult Males ◽  
Supplemental Food ◽  
Randomized Design ◽  
Acclimation Period ◽  
Completely Randomized Design ◽  
Relative Palatability

Abstract Speed of action was determined for a bait containing 0.5% chlorpyrifos against both a susceptible (JWax-S) and insecticide-resistant (Muncie’86) strain of German cockroaches. Thirty insects were used in the test, 10 each of the following age/sex classifications: 1) adult males; 2) virgin females; and 3) 4th instar nymphs; all insects were newly eclosed (<48 h of eclosion). Cockroaches were housed in 30 × 24 × 10 cm plastic boxes supplied with harborage (positioned in center of arena), 2 water vials (positioned along walls of arena), and 4 food dispensers (2 × 2-cm weigh boats positioned in the corners). Arenas were made escape-proof by use of ventilated, friction-fitted lids and an impassable barrier of petrolatum and mineral oil (1:2) on the arena walls. Two bait placement schemes were used: 1) no-choice, where the bait (3.5 g) was divided between opposing corners of the arena; and 2) choice, wherein supplemental food sources (3.5 g of Wayne® rodent blox and grape jelly) were placed in the alternate corners of the arena. Each treatment was replicated 3X using a completely randomized design. Insects were released into the arenas and, after a 24-h acclimation period, toxic bait and food sources were introduced to the arenas in a random order. Mortality was analyzed with ANOVA models to characterize the significance of the differing baiting schemes (choice vs. no-choice) and insect strains (susceptible vs. resistant). Speed of kill (LT50 and LT,5) was determined by probit analysis of cumulative mortality and a ratio test estimated the relative palatability (PR) of the bait for each strain, as inferred from differential LT50 and LT95 between choice and no-choice bioassays.

Pregnancy rates and serum progesterone levels of polar bears in western Hudson Bay

1992 ◽  
Vol 70 (3) ◽  
pp. 561-566 ◽  
Author(s):  
Andrew E. Derocher ◽  
Ian Stirling ◽  
Dennis Andriashek
Keyword(s):  
Minimum Weight ◽  
Pregnancy Rates ◽  
Hudson Bay ◽  
Polar Bears ◽  
Age Classes ◽  
Serum Progesterone ◽  
Pregnant Females ◽  
Fat Stores ◽  
First Time ◽  
Old Females

Blood samples were collected from 354 female polar bears (Ursus maritimus) on 476 occasions between 1982 and 1990. Serum progesterone concentrations were determined to evaluate reproductive status. Progesterone levels greater than 2.5 ng/mL were considered indicative of pregnancy in autumn. Of 85 females classified as pregnant that were seen the following year, 67% were with cubs and 33% were without cubs. Possible explanations for the large proportion of females with apparent reproductive failure include neonatal mortality, failure to implant, or abortion. The minimum weight of a confirmed pregnant female in autumn was 189 kg, but approximately 10% of the suspected pregnant females were below this and may have had insufficient fat stores to fast through the winter and produce cubs. Based on progesterone levels, implantation appeared to occur between mid-September and mid-October, likely followed by parturition from mid-November to mid-December. The annual pregnancy rate of solitary females, as determined by progesterone concentrations, varied between 82.4 and 100%, but the differences were not significant. Females bred for the first time between 3 and 5 years of age, at an average of 4.1 years. The age-specific pregnancy rates of 3- to 4-year-old females and females 21 years and older were lower than those of other age-classes. However, some older females appear to retain reproductive competency throughout their life.

scholarly journals Speed of Action in Siege and Maxforce Gel Baits, 1995

1996 ◽  
Vol 21 (1) ◽  
pp. 391-392
Author(s):  
Walid Kaakeh ◽  
G. W. Bennett
Keyword(s):  
Regression Analysis ◽  
Random Order ◽  
Food Sources ◽  
Adult Males ◽  
Supplemental Food ◽  
Randomized Design ◽  
Acclimation Period ◽  
Ca 50 ◽  
Completely Randomized Design ◽  
X 24

Abstract Speed of action was determined for Siege and Maxforce baits (2.0 and 2.15% hydramethylnon, respectively) against the JWax susceptible strain of the German cockroach. Forty insects were used in the test, 10 each of the following age/sex classifications: 1) adult males; 2) newly mated females; 3) 4th instar nymphs; and 4) 2nd instar nymphs; all insects were newly eclosed (<48 h of eclosion). Cockroaches were housed in 30 X 24 X 10 cm plastic boxes supplied with two water vials (positioned along walls of arena) and two food dispensers (2X2 cm weigh boats positioned in the corners). Arenas were made escape-proof by use of ventilated, friction-fitted lids and an impassable barrier of petrolatum and mineral oil (1:3) on the arena walls. Baits were applied in ca. 50 mg portions within a specially constructed crack and crevice device. These were fashioned from a 1“ by 1” piece of particle board and a 1“ by 1” piece of unpainted plywood, these being separated at a distance of 0.25” by a pine strip glued along one edge. Baits were applied as single 50 mg spherical beads. Siege was applied from the Xactadose Precision Baiting System; Maxforce was applied from the manufacturer’s syringe. Once the baits had been applied in the crack and crevice device, they were stored in lab-cabinets. Here the baits were aged for 0, 3, 7, 10, 14, 28, 56, and 90 d before bioassay. Two bait placement schemes were used: 1) no-choice, where the bait in the device was placed in the opposing corners of the arena; and 2) choice, where supplemental food sources (2.5 g of Wayne™ rodent blox and grape jelly) were placed in the alternate corners of the arena. Cockroaches were released into the arenas and after a 24-h acclimation period, toxic baits and food sources were introduced to the arenas in a random order. Each combination of bait, competition, and aging was replicated three times in a completely randomized design. The speed of kill (LT50, LT95) for each combination of bait, competition, and aging was determined by regression analysis of cumulative, probit mortality against the log 10 of time (d). Further, palatability ratios (PR50, PR95) were determined by comparing the statistics in the regression analysis of the cumulative mortality in the choice bioassay to those in the no-choice bioassay for each combination of bait and aging.

scholarly journals Modeled replacement of traditional soybean and canola oil with high-oleic varieties increases monounsaturated fatty acid and reduces both saturated fatty acid and polyunsaturated fatty acid intake in the US adult population

2018 ◽  
Vol 108 (3) ◽  
pp. 594-602 ◽  
Author(s):  
Susan K Raatz ◽  
Zach Conrad ◽  
Lisa Jahns ◽  
Martha A Belury ◽  
Matthew J Picklo
Keyword(s):  
At Risk ◽  
Fatty Acids ◽  
Fatty Acid ◽  
Canola Oil ◽  
Food Sources ◽  
Fatty Acid Intake ◽  
High Oleic ◽  
Acid Intake ◽  
The Us ◽  
Age And Sex

ABSTRACT BACKGROUND High-oleic (HO) seed oils are being introduced as replacements for trans fatty acid (TFA)–containing fats and oils. Negative health effects associated with TFAs led to their removal from the US Generally Recognized As Safe list. HO oils formulated for use in food production may result in changes in fatty acid intake at population levels. Objectives The purposes of this study were to 1) identify major food sources of soybean oil (SO) and canola oil (CO), 2) estimate effects of replacing SO and CO with HO varieties on fatty acid intake overall and by age and sex strata, and 3) compare predicted intakes with the Dietary Reference Intakes and Adequate Intakes (AIs) for the essential fatty acids (EFAs) α-linolenic acid (ALA) and linoleic acid (LA). Design Food and nutrient intakes from NHANES waves 2007–2008, 2009–2010, 2011–2012, and 2013–2014 in 21,029 individuals aged ≥20 y were used to model dietary changes. We estimated the intake of fatty acid with the replacement of HO-SO and HO-CO for commodity SO and CO at 10%, 25%, and 50% and evaluated the potential for meeting the AI at these levels. RESULTS Each modeling scenario decreased saturated fatty acids (SFAs), although intakes remained greater than recommended for all age and sex groups. Models of all levels increased the intake of total monounsaturated fatty acids (MUFAs), especially oleic acid, and decreased the intake of total polyunsaturated fatty acids (PUFAs), particularly LA and ALA. Replacement of traditional with HO oils at 25–50% places specific adult age and sex groups at risk of not meeting the AI for LA and ALA. Conclusions The replacement of traditional oils with HO varieties will increase MUFA intake and reduce both SFA and PUFA intakes, including EFAs, and may place specific age and sex groups at risk of inadequate LA and ALA intake.

scholarly journals Estimation of Starch and Sugar Intake in a Japanese Population Based on a Newly Developed Food Composition Database

Nutrients ◽  
2018 ◽  
Vol 10 (10) ◽  
pp. 1474 ◽  
Author(s):  
Aya Fujiwara ◽  
Kentaro Murakami ◽  
Keiko Asakura ◽  
Ken Uechi ◽  
Minami Sugimoto ◽  
...  
Keyword(s):  
Preschool Children ◽  
Dairy Products ◽  
Age Groups ◽  
Food Composition ◽  
Total Sugar ◽  
Food Sources ◽  
Sugar Intake ◽  
Dietary Record ◽  
The Mean ◽  
Age And Sex

Due to a lack of a food composition database on starch and sugars, we developed a comprehensive database on starch and seven types of sugars in commonly consumed foods (n = 2222) in Japan. Dietary record data of 368 toddlers (aged 18–35 months), 376 preschool children (aged 3–6 years), 915 schoolchildren (aged 8–14 years) and 392 adults (aged 20–69 years) were used. The mean starch intake ranged from 55.6 g/day (female toddlers) to 206.0 g/day (male schoolchildren). Irrespective of age and sex, >50% of starch was provided by rice and grains. The mean total sugar intake ranged from 46.1 g/day (female toddlers) to 68.7 g/day (male schoolchildren). In all age and sex groups, the major contributors of total sugar included sucrose (mean: 18.2–34.0 g/day), glucose (7.8–13.1 g/day), lactose (5.3–13.1 g/day) and fructose (7.6–11.1 g/day). The top food sources were dairy products (toddlers) and confectionaries (other age groups) for total sugar, confectionaries for sucrose, fruits (toddlers) and vegetables (other age groups) for glucose, dairy products for lactose and fruits (toddlers and preschool children) and vegetables (schoolchildren and adults) for fructose. In conclusion, this study clarified the starch and sugar intake in Japan and provides a foundation for future research.

Concentrations of legacy and new contaminants are related to metabolite profiles in Hudson Bay polar bears

2019 ◽  
Vol 168 ◽  
pp. 364-374 ◽  
Author(s):  
A.D. Morris ◽  
R.J. Letcher ◽  
M. Dyck ◽  
B. Chandramouli ◽  
J. Cosgrove
Keyword(s):  
Hudson Bay ◽  
Polar Bears ◽  
Metabolite Profiles

scholarly journals Offspring and adult chemosensory recognition by an amphisbaenian reptile may allow maintaining familiar links in the fossorial environment

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e10780
Author(s):  
José Martín ◽  
Ernesto Raya-García ◽  
Jesús Ortega ◽  
Pilar López
Keyword(s):  
Parental Care ◽  
Chemical Cues ◽  
Kin Recognition ◽  
Social Groups ◽  
Tongue Flick ◽  
Adult Males ◽  
Stable Family ◽  
Males And Females ◽  
Family Groups

Kin recognition is a phenomenon with an important function in maintaining cohesive social groups in animals. Several studies have examined parent–offspring recognition in species with direct parental care. Few studies have, however, explored parent–offspring recognition in animals that, at best, only show apparent indirect parental care, such as some reptiles. In this study, we investigated reciprocal parent–offspring recognition in the fossorial amphisbaenian Trogonophis wiegmanni, a viviparous species that shows potential stable ‘family groups’ in the form of parent-offspring long-term associations. We examined whether adult males and females could discriminate via chemical cues between familiar juveniles which associate with them within their family groups, and are potentially their offspring, to that of unfamiliar juveniles, and whether juveniles could discriminate between familiar adult males and females of their family group (probably their parents) and unfamiliar unrelated adults. We measured tongue flick behavior to study chemosensory responses to the scent of conspecifics. We found that adult female amphisbaenians, but not males, could discriminate between scents of familiar and unfamiliar juveniles. Juvenile amphisbaenians did not discriminate between familiar and unfamiliar adult females, but recognize familiar from unfamiliar males. We discuss our results of parent–offspring recognition according to its potential social function in an ecological fossorial context where visibility is limited and chemosensory kin recognition may contribute to the establishment of stable family groups.

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