The cubs have absolutely incredible energy levels!
I can see what a big difference it makes to have a sibling. Several sows in our neck of the woods have only one cub this year. I bet that being a bear mom is a lot harder with a solo cub!
The cubs did not only play during the day. They played all night too! They'd take short naps when my cams would pick up no activity but then start again within an hour or so. Here they were at 11:30 at night!
The chocolate male cub was working on pulling himself up onto a branch while his sister watched.
Poor mom got no sleep. She stayed in the den with her eyes open all the time that the cubs played at night.
I am including a video to show the cubs playing. It also shows mom taking a walk and coming back with a single pine branch. It seemed bizarre to see her carefully pull the branch into the den with her. I've always thought that the floor of the den looks like a very hard surface to spend an entire winter lying on. There's not much forest duff to drag into the den to make a soft bed. But I hardly think that one pine branch would help much!
You can watch the video here or at Youtube. Enjoy!