YELLOWSTONE NATIONAL PARK — According to a Monday, Dec. 30, Facebook post by Yellowstone National Park (YNP), baby bears are beginning to grow inside their mothers after delayed implantation due to hibernation.
YNP writes that when a female bear mates in the summer, the embryo doesn’t start growing until she is in hibernation. This delay allows the body to wait until the mother is in good enough condition inside her den to give birth to a healthy cub.
The delayed implantation occurs in December, as the embryos in pregnant female bears implant in the uterus and begin developing. In 60 to 70 days, the cubs will be born while the mother still hibernates.
YNP writes on its website that female bears will typically emerge with their cubs around the fourth week of April.
