Bears, hibernation

C06-0136. The heat required to sustain animais that hibernate comes from the biochemicai combustion of fatty acids, one of which is arachidonic acid. For this acid, (a) determine its structurai formuia (b) write its baianced combustion reaction (c) use average bond energies to estimate the energy released in the combustion reaction and (d) caicuiate the mass of arachidonic acid needed to warm a 500-kg bear from 5 to 25 °C. (Assume that the average heat capacity of bear flesh is 4.18 J/g K.)... 

An interesting possibihty, never investigated, is that the bear possesses the ability to synthesise both dispensable and non-dispensable amino acids de novo, from the ammonia released by the microorganisms. As far as is known, no mammal possesses the enzymes necessary to synthesise the indispensable amino acids. It would be interesting if another adaptation to such a long hibernation is development of enzymes necessary to synthesise indispensable amino acids. This possibility is supported by the... 

In this chapter we will consider the cosmochemistry of ice-bearing planetesimals. We will focus first on comets, because more is known about their chemistry than of the compositions of objects still in the Kuiper belt and Oort cloud. We will then explore asteroids whose ices melted long ago, and we will briefly consider some larger icy bodies, now represented by satellites of the giant planets. The importance of ice-bearing planetesimals to cosmochemistry stems from their primitive compositions, which have remained largely unchanged because of hibernation in a frozen state. 

In some animals, triacylglycerols stored under the skin serve not only as energy stores but as insulation against low temperatures. Seals, walruses, penguins, and other warm-blooded polar animals are amply padded with triacylglycerols. In hibernating animals (bears, for... 

A grizzly bear prepares its hibernation nest, near the McNeil Fiver in Canada. 

In mammalian hibernators, the reduced amount of urea that is formed also is cycled through to the gut, where it is hydrolyzed by intestinal bacteria and the released ammonia is re-utilized. In bears, which Nelson et al. (1998) argue have developed hibernation to its epitome among mammals, these metabolic processes are fine tuned to perfection the animal becomes a self-sustained closed metabolic support system with no carbon or water intake, no urine or digestive waste, and only a modest drop in body temperature (down to about 32°C). 

Barnes, B.M., O.Toien, J. Blake, D. Grahn, H.C. Heller, and D.M. Edgar (1999). Hibernation in black bears temperature cycles and sleep. FASEB J. 13 A740. 

Many mammals in the animal kingdom rely on fat that is stored in their bodies. By surviving on fat reserves that are stored during the autumn, bears can hibernate throughout the winter without eating. 

Many aspects of the panda s skeletal structure and behavior support the idea that it is not a bear. An especially important piece of evidence is the presence of a special sixth digit, which acts in the manner of an opposable thumb. This digit is actually an extension of a bone in the wrist, and it allows giant pandas to grasp bamboo shoots and efficiently strip off their leaves. The red panda also has such a thumb, although it is less well-developed. Other aspects of panda biology which bears do not possess include well-developed molar teeth and non-hibernation in winter. 

How are bears able to stay warm enough to keep from freezing during their winter hibernation How do marathon nmners get the energy to finish a race without stopping to eat In both cases, fats stored in the body are oxidized. Oxygen molecules from the air are reduced as they gain electrons to form water. In a series of redox reactions called respiration. 

Berries seeds By planting species that bear berries and fruits, and leaving seedbearing stems standing at the end of the growing season, you will help birds and small mammals survive the winter months when their natural food sources are greatly reduced. Standing stems also provide hibernation sites for insects. 

Lipid metabolism allows polar bears to thrive In arctic climates and to endure months of hibernation. 

Prior to hibernation, a polar bear eats food with a high content of fats and oils. 

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