Sun bears are tropical so they are thiner because of allens rule, so their proortions are more humanlike. When bears stand uprigth they stand on their heels unlike most large mamals. Thats why their posture looks earily human. And thats why sir berington remained undiscovered for so long. As a contrast take daji, since she was a fox spirit she walked on the balls of her feet. Leading to the misconception that her feet were small, and ultimatley to the practice of footbinding.