A mother who has not eaten since leaving the ice, now nearly six months ago, is able to nourish her cubs in utero and yet still keep her metabolism quiet enough to conserve energy for at least three more months of fasting to come. Because, in addition to her own considerable insulation — two inches of thick downy underfur combined with a full mantle of long hollow guard hairs — every bear has her coating of fat just below the skin. The well-insulated snow cave that is the den can be warmed to just below freezing with nothing more than the presence of a warm bear.
Kanlaon 