The blastula then implants in the uterine wall and continues to develop. Delayed implantation assures that the cub is born during the best time of the year for survival and allows the female to get into good physical condition and use her energy for nursing her newborn cubs. The actual embryonic development is estimated to be four months. 1.Once mated, females begin depositing fat in preparation for cubbing. 2.Some females may seek out maternity dens as early as late August, but most enter dens in mid to late October.
Dens protect newborn cubs from winter's temperature extremes.
3.Females usually dig dens in snowdrifts on southerly facing slopes. Some dig earthen dens that later become covered by snow. Most dens consist of a single chamber slightly elevated from a short entrance tunnel. 7.Because of body heat and snow insulation, the den stays warmer than the outside air temperature. C. Birth seasons.