Introduction
Polar bears are a range of bears from the family Ursidae and genus Ursus that natively lie within the boundaries of the Arctic Circle which well includes the landmasses and surrounding seas around the Arctic Ocean . Considering the native geographical location where the polar bears reside, it can be safely assumed that these creatures live in a predominantly cold weather environment . In terms of general physical features, a male adult polar bear should weight somewhere around 770 to 1,500 lbs. ; a female adult on the other hand should be somewhere around half of this size . Polar bears are a sister specie of the brown grizzly bear which should explain why the two creatures exhibit some extent of physical and even behavioral similarities . The former however, belongs to a significantly narrower ecological niche with physical characteristics designed and adapted for extremely cold temperatures and for hunting preys that also reside and thrive in the same environment such as seals, dolphins, and penguins .
The objective of this paper is to discuss an academic issue relating to polar bears by means of conducting a comprehensive review of related literatures found on credible and established premium academic databases.
Hibernation and Seasonal Fasting in Bears: The Energetic Costs and Consequences for Polar Bears
Food sources for mammals (one of the few best examples of which would be the polar bears) in the Arctic and nearby feasibly livable locations are not constant. Mammals in these places can only have access to their food sources during times when the land masses are accessible to hunting. Polar bears largely depend on ice or iced landmass at least for access to hinting. Without these ice and landmasses, the creatures would have to fare and swim through ice-cold water and compete with their preys’ fast underwater movements which would prove to be impractical considering the limited recommended amount of energy that polar bears should have for every hunting session and the theoretical success rate of such approach in hunting. Unfortunately, because of harmful and often unseen effects of global warming, these creatures’ access to ice and landmasses (which they need for hunting) has been on a continuously decreasing state. After continuous hunting sessions and with sufficient energy and fat reserves in their body, polar bears would usually hibernate. Of course, the maximum length of hibernation would depend on the amount of energy and fats they were able to store. This factor would of course depend on the quality and success of their hunts which in turn can be directly affected by their access to their hunting grounds. The objective of Robbins et al.’s study was to determine the effects of global warming on the energetic costs of polar bears. What he and his research team have found out was a decrease in the average maximum hibernating time among lactating and pregnant polar bears. This finding totally makes sense considering the linearity of the relationship that exists between global warming and the polar bears’ access to their main hunting grounds—the ice and arctic landmasses.
Future Sea Ice Conditions in Western Hudson Bay and Consequences for Polar Bears in the 21st Century
It has been mentioned before that the polar bears’ main hunting grounds are the ice and the landmasses near ice surfaces. In general, this is true but in other specific parts of the arctic such as the Hudson Bay—one of the most famous and large-scale habitats of polar bears, a more specific polar bear behavior can be observed. In Hudson Bay, particularly the western part of it, every summer, the size of the ice surfaces naturally diminishes. This phenomenon resultantly drives the polar bears—who are more used and adapted to living in ice and iced landmasses, ashore. Numerous other studies have directly correlated the survival of the polar bears with the ice buildup and breakup cycle or phenomenon in Western Hudson Bay. Such studies have arrived to the conclusion that if the ice buildup and break up threshold in Western Hudson Bay would continue to increase and be disturbed, the polar bear population in the area may be negatively affected. One of the said culprits behind the fluctuating thresholds in the ice buildup and breakup cycle in the area is global warming. Results of Castro de la Guardia’s study suggest that “the habitat of polar bears in Western Hudson Bay will experience further deteriorations in the 21st century as ice predictions in the reviewed polar bear populations show that the polar bear population may struggle to persist after 2050.” The research team also looked into some possible solutions as to how the predicted polar bear population struggle by 2050 could be prevented and one suggestion was the reduction of GHG emissions which could allow the creatures to continuously breed and exist in Western Hudson Bay way past the 21st century.
Individual and Environmental Factors Associated with Stereotypic Behavior and Fecal Glucocorticoid Metabolite Levels in Zoo Housed Polar Bears
Even though the answer to the question whether there is any real difference in the behaviors and physical and chemical features between free-roaming and zoo housed polar bears is already somewhat obvious, most animal scientists and zoologist continue to speculate. The objective of this study was actually related to that issue. In this study, Shepherdson et al. attempted to observe and point out behavioral and other differences that might exist between free-roaming and zoo-housed polar bears. What they found out was sensible. According to their findings, the free-roaming and zoo-housed polar bear groups observed in their studies exhibited significant differences in areas of temperament, interests, stereotypic pacing, and stress, and other negative behaviors which mainly existed among the subject zoo-housed polar bears in the study. As a recommendation, the authors stated that “exhibit designers should consider providing polar bears with a view out of their exhibit and larger land areas associated with their natural habitats; and should proactively identify the individuals who are most likely to develop pacing behaviors and provide appropriately enhanced care before any negative behaviors become regular and established” .
A Circumpolar Monitoring Framework for Polar Bears
This study focused on the monitoring of polar bears, particular the ones who occupy remote regions characterized by harsher than normal weathers and limited access to energy sources and hunting grounds. Some factors that were closely looked into in this study were the different stressors to the different populations of polar bears. The extent of positivity or negativity of such stressors on the polar bear populations was also observed. Results of this research showed that there may have been some discrepancies with the way how traditional and previously published studies have identified the polar bear population stressors and their positive and negative effects on the creatures’ lifestyle and even survival rate. The research group recommended that a dynamic and a more easily adopted information management framework be created and established in order to make policy responses to changing worldwide polar bear status and trends easier, and more efficient.
Bibliography
Calvert, W., & Stirling, I. (2009). Interactions Between Polar Bears and Overwintering Walruses in the Central Canadian High Arctic. Journal of Zoology, 351-356.
In this study, the authors, Calvert, and Stirling (2009) attempted to discuss the different possible effects and implications of overwintering on the overall lifestyle of walruses and polar bears in the a specific geographical location particularly the Canadian High Arctic. The authors, based on the results of their study, suggest that overwintering leads to harmful effects on the behavior, lifestyle, and even the hunting habits of polar bears and walruses.
Castro de la Guardia, L., Derocher, A., Myers, P., Terwisscha van Scheltinga, A., & Lunn, N. (2013). Future Sea Ice Conditions in Western Hudson Bay and Consequences for Polar Bears in the 21st Century. Journal of Global Change Biology, 2675-2687.
Castro de la Guardia et al.'s (2013) objective was to study the different factors that come into play on the future sea ice conditions in Western Hudson Bay, a place believed to be among the largest and most populated polar bear habitats in the planet. Results of their study suggest that polar bears may experience difficulties surviving in Western Hudson Bay by 2050s, if the rate of the world's global warming would continue.
Derocher, A., & Wilg, O. (2002). Postnatal Growth in Body Length and Mass of Polar Bears at Svalbard. Journal of Zoology, 343-349.
In this research, the authors Derocher and Wilg (2002) attempted to determine the standard length and mass of polar bars in a specific location particularly at Svalbard. At the end of the study, the two authors were able to set generalized standards--based on the relatively medium-sized polar bear population they studied in their research, on the size of both male and female polar bears.
Heyland, J., & Hay, K. (2006). An Attack by a Polar Bear on a Juvenile Beluga. Journal of the Arctic, 56-57.
The objective of this study by Heyland and Hay (2006) was to document and rationalize the events that happened during an attack by a polar bear on a juvenile beluga. At the end of the paper, the authors were able to conclude that the most likely reason why a polar bear attacked the Juvenile Beluga victim was the lack of choice of preys secondary to the destruction of their habitats.
Kolenosky, G. (2007). All About Polar Bears in Wild furbearer Management and Conservation in North America. Ontario Fur Trappers Association Ontario Canada, 44.
The objective of this study by Kolenosky (2007) was to investigate on the different efforts that the local and state government exert to protect the polar bear populations and whether they can prove to be effective strategies or otherwise. Results of the study suggest that the wild furbearer management and conservation in North America is a model government program that other government and non-government organizations should follow.
Macdonald, D., & Barrett, P. (2003). Mammals of Europe. Princeton University Press, 14.
Macdonald and Barrett (2003)'s objective was to document the different physical and behavioral characteristics of the different mammalian species in Europe. Polar bears were among the highlights of their work.
Paetkau, S., Amstrup, C., Born, E., Calvert, W., Derocher, A., Garner, G., et al. (2009). Genetic Structure of the World's Polar Bear Populations. Journal of Molecular Ecology, 1571-1584.
Paetkau et al. (2009) attempted to study the genetic structure of the world's polar bear populations and spot out relationships that may exist on the differences on their genetic structures and on the differences between each polar bear population's behaviors, physical attributes, etc.
Robbins, C., Lopez, C., Rode, K., Toien, O., & Nelson, L. (2012). Hibernation and Seasonal Fasting in Bears: The Energetic Costs and Consequences for Polar Bears. Journal of Mammalogy, 1493-1503.
Robbins et al. (2012) structured their research in a way that they would be able to examine the different aspects and effects of overwintering on hibernation and seasonal fasting in bears. The results of their study suggest that certain polar bear populations can only last so long hibernating and fasting, particularly the lactating and pregnant polar bear populations.
Shepherdson, D., Lewis, K., Carlstead, K., Bauman, J., & Perrin, N. (2013). Individual and Environmental Factors Associated with Stereotypic Behavior and Fecal Glucocorticoid Metabolite Levels in Zoo Housed Polar Bears. Applied Animal Behavior Science, 268-277.
The objective of Shepherdson et al. (2013) in their study was to differentiate the behaviors, physical attributes, and other related factors between a population of free-roaming and zoo-housed polar bears. Results of their research suggest that zoo housed polar bears typically exhibit more aggressive and atypical behaviors compared to free-roaming ones.
Stirling, I. (2007). The Importance of Polynas, Ice edges, and leads to Marine Mammals and Birds. Journal of Marine Systems, 9-21.
Stirling (2007) investigated on the importance of polynas, ice edges, and leads to marine mammals and birds, which well includes polar bears that live in the arctic continent. Results of their research suggest that the availability and accessibility of Polynas and Ice edges affect the hunting lifestyle and even the diet and nutrition of polar bears.
Thiemann, G., Iverson, S., Stirling, I., & Obbard, M. (2011). Individual Patterns of Prey Selection and Dietary Specialization in an Arctic Marine Carnivore. Journal of Zoology, 1469-1478.
Thiemann et al. (2011) investigated on the individual patterns of prey selection and dietary specialization among polar bears and other arctic carnivores. Results of their study suggest that polar bears would normally stick to their normal and typical prey selections unless there are no other choice but to attack all edible preys.
Vongraven, D., Aars, J., Amstrup, S., Atkinson, S., Belikov, S., Borns, e., et al. (2012). A Circumpolar Monitoring Framework for Polar Bears. Journal of Ursus Monograph Series, 1-66.
Vongraven et al. (2012) attempted to create and suggest a circumpolar monitoring framework for polar bears in an effort to maximize their access to the lifestyle information of polar bears. The authors recommend the creation of a geographically-based monitoring framework for polar bears because of their perceived promising results.
Wood, G. (2003). The Guinness Book of Animal Records. The Guinneess Book of Animal Records, 240.
Wood (2003) authored the appraisal of the Guinness Book of Animal Records which featured several useful information about polar bears, and other types of animals.
