Why do bears hybernate?
924163
Bears have a diet that is mostly based on berries, fish and the occasional animal that might wander around.  Berries are missing in winter, and fishing is hard to do owing to the ice that covers lakes (and fish are not as active anyway), and looking for the odd animal it could catch would be time and energy consuming; perhaps not a good move from an energy point of view (the bear would spend more energy to hunt that it owuld get from eating the animal it could catch; bears are solitary animals as do not have the hunting success a pack of wolves might have).\n\nSo, it makes good sense for them to "close" shop for the winter, and live off the fat they accumulated in the summer and fall.
773670
So their body can react properly to keep them warm.\n\nSo they can avoid predators\n\nSo they can find prey\n\nThere's 3
394462
polar bears are threatened by the spread of hormone-disrupting chemicals and global warming. This affects the polar ice edge ecosystem, the habitat of walrus, seals and penguins, as well as bears. \n\nMORE INFO ON THE LINK BELOW :)
223973
They are less active in winter but they don't migrate. It was just looking for a place to rest for a minute that offered a little shelter from the weather.
852100
In arcatic region of Canada polar bear sleep most
1177195
Bears because they will attack you back
605091
Frogs hibernate in burrows or under leaves or bury themselves in mud. Their organs contain a high concentration of glucose which prevents the frogs from freezing.
165508
Both the huskie and polar bear have fur that is made to keep them warm in cold weather. Both can become uncomfortable and possibly overheat if the weather is not cool enough. They are made to be in the cold and removing them from that situation is rather cruel to the animal. The huskie has adapted to humans, becoming a pet and work animal while the bear is more an equal if not slightly higher. \nI am basing this on a Nature special about polar bears on PBS.
623624
When fall turns to winter and the temperature dips, the food sources for the wild animals becomes very scarce.  Some animals wait out the harsh conditions of winter, constantly searching for food and shelter.  Other animals, like the bear, spend the winter in hibernation. \n     Hibernation is a dormant sleep-like state.  By going into hibernation the bears bypass winter when their food supply, nuts and berries, disappears.  Animals like the bear would find it extremely difficult to find enough food during winter, and therefore go into hibernation. \n\n     During hibernation the bear cuddles up in a cave or in a hollowed out tree, safe from the dangers of winter.  In order to survive this long period of inactivity the bear must build up its body weight by accumulating fat.  In the months before  hibernation bears can gain up to forty pounds of fat per week.   A bear’s body goes through several changes once it enters hibernation.  Its heartbeat drops from fifty-five beats per minute to ten beats per minute, and the bear’s body temperature will drop from five to nine degrees below normal.  While in hibernation the bear uses  the stored energy it accumulated as fat to survive.  So a bear can lose from fifteen to forty percent of its body weight during the winter just by sleeping! \n\n     Bears will generally enter hibernation in early October and emerge sometime in April or May, when their food is plentiful again.  The hibernation cycle is just another unique adaptation of nature that allows many animals like the bear to survive during the severe conditions of winter time. \n\nhope this helps.
1065431
because their menstration cycles attracts bears and then we would have to fight ragheads and bears at the sametime
292689
On extremely cold days many birds will roost to conserve heat. If they take to the air they expose their underwings and bodies, and the short insulating feathers under the flight feathers are exposed to the cold air, so they no longer provide adequate insulation.
795780
some of them might hibernate. hibernation allows some small mammals to reduce their metabolism during times of scarce resources, such as winter. they accumulate body fat for a while, then it's like their system «shuts down»: their body temperature decreases, their pulse too, and they might breathe as few as 1 to 10 times a minute!\nhibernation is a real advantage because, when it's cold, it would take a lot more energy to keep normal body heat, consuming more nutrients, when, in fact, it's the time of year when it's more difficult to feed!
504847
It gets colder. So clearly not isothermal (which means it stays the same temperature). It's adiabatic because no energy is released or absorbed.
882444
They can hunker down in deep grasses. The snow and grass act as insulation keeping them warm.\n\nWhat's cooler (pun intended) than this is to look at tree squirrels, who have nests high in trees open to the blowing wind. Even they stay warm while being that exposed. The nests help trap body heat while breaking the wind.\n\nNature has some remarkable methods to keep animals warm.
1041975
I concur with answerer 2 and have been reading a lot in the news on the internet and seeing alot on television about it including the information she cited about the polar bears. You see, due to global warming the pack ice in the arctic forms much later than usual. This means seals do not haul themselves out onto the ice as soon as they used to, which in turn means polar bears can't kill and eat them when they are hungry. Also, the pack ice retreats much sooner than normal, and again this means a polar bear cannot fatten up for the summer.\n\nPolar bears are attempting to swim much longer distances than they are capable of in order to find food. They drown. A marine biologist interviewed on the TV said in decades of scientific research this is the very first time he'd ever heard of a polar bear actually drowning.\n\nYou see global warming affects arctic environments much more acutely than temperate ones. Even a few degrees of change in the average temperature can spell disaster for the wildlife there.
915703
They dont!! Sorry to say it but that's why you see some animals dead :(.\nHoweverm they do know winter's comming up...it  kinna get cooler
1132322
This joke/riddle is so old. The bear is white cause you are at the North pole.