Bears are adapted to changing seasons. In the summer they eat a lot of food so in the winter they have a lot of fat to live off of.
In the winter the Bears settle down in there dens to hibernate because they can't really go hunting because they eat fish and lakes and rivers are frozen.
So in the winter they stay in there dens mostly sleeping a lot. When they wake up they usually have food that they packed in the summer.
So in the winter they keep food in a corner so they can eat that the whole winter and they have to take care of here babies too and feed them too.
At one point in there hibernation they wake up and they good hunting because they ran out of food or to have more food so they make a whole in the ice with there sharp claws and goes in and grabs the fishes.
When the summer comes they go hunting al day and they eat a lot and store food so when its winter again there prepared and these are how bears hibernate.