The Polar and Tropical Worlds: A Description of Man and Nature by Georg Hartwig

Details from cover

From the book...

"The she-bear is taught by a wonderful instinct to shelter her young under the snow. Towards the month of December she retreats to the side of a rock, where, by dint of scraping and allowing the snow to fall upon her, she forms a cell in which to reside the winter. There is no fear that she should be stifled for want of air, for the warmth of her breath always keeps a small passage open, and the snow, instead of forming a thick uniform sheet, is broken by a little hole, round which is collected a mass of glittering hoar-frost, caused by the congelation of the breath. Within this nursery she produces her young, and remains with them beneath the snow until the month of March, when she emerges into the open air with her baby bears."