Introduction
The black and brown bears are similar to many mammals; they all undergo hibernation, especially during winter seasons, to protect themselves against periods of shortages of food. Unlike most mammals, bears undergo mild hypothermic hibernation (or dormancy), this will enable them with their metabolism only by 20-50%, and they arouse easily if awake. To prepare for the long periods of the deprivation, the bears tend to become, hyperphagic especially in the periods of autumn to build their reserves for fats soluble. Their intake in calories tends to increase to 15-20,000kcal/day significantly. This intake is more than twice from their consumption from the summer season. Bears also tend to become hyperinsulinemic; this means they manage o develop insulin resistance characteristics. After all this, the bears tend to retreat into their dens during the winter periods. They remain there for 5 to months. During the hibernation period, they become inactive physically. Bears during this period tend to sleep with slightly depressed body temperatures (30-35 degrees Celsius).
To maintain their body temperatures, bears undergo a period of muscle shivering; they do not appear to use any fat that is brown mediated that causes no shivering thermogenesis (Nelson, 2015). Therefore, as part of their metabolic rate reduction, this bears also tend to become Brady cardiac, with a heart rate of 8-10b.pm. This is unlike their current price, which is 40 b.p.m. there is also a decrease in their standard of basal by 40% with their oxygen consumption being 50% of normal. During their hibernation, bears do not move, eat, drink, urinate or defecate. Through the fact that they were able to store, these bears can survive. The stored fats in their bodies are metabolized to become water to help the bears stay hydrated (Nelson, 2015).
As it comes to the end of the summer season, bears tend to be more active; they begin hunting for food; they eat and drink non-stop (Evans, 2016). Generally, it is essential to understand that the tissue that fuels hibernation is fat, and it also orchestrates the sparing of other tissues. Therefore through a fasting bear during the active season, does not allow the making of the same genes in the off and on the switch. Most researchers have speculated the bear as they prepare for hibernation, they tend to eat more of indigestible plants to activate and purge their digestive tracts into forming a rectal plug to prevent excessive eating (Evans, 2016). The bear eats as much as 90 pounds of food each day as they prepare to hibernate, the brown bears also tend to dig up dens for the hibernation period; these dens are mostly dug up along the suitable hillside. At times supplemental foods are provided to these bears during periods of fall, they tend to abandon the supplements so that they hibernate in the time since they are genetically programmed to do so.
References
Berg von Linde, M., Arevström, L., & Fröbert, O. (2015). Insights from the den: how hibernating bears may help us understand and treat human disease. Clinical and translational science, 8(5), 601-605.
Evans, A. L., Singh, N. J., Friebe, A., Arnemo, J. M., Laske, T. G., Fröbert, O., … & Blanc, S. (2016). Drivers of hibernation in the brown bear. Frontiers in zoology, 13(1), 7.
Nelson, O. L., & Robbins, C. T. (2015). Cardiovascular function in large to small hibernators: bears to ground squirrels. Journal of Comparative Physiology B, 185(3), 265-279.