Is it normal for a golden bear to bleed in his mouth when he gives birth to a cub?

Normal. Oral bleeding is normal when golden bear gives birth to cubs, which is caused by improper handling of mother silk during production. If there is not much bleeding and there is no continuous bleeding, don't worry. Try to put them in a quiet and air-friendly environment. Because gold wire will be very weak after production, and gold wire itself doesn't like noisy environment.