Can female polar bear protect cubs from male polar bear?

Male bears kill cubs not out of hunger, but because infanticide will result in a female going into estrous earlier than if she had to raise the cubs. If the male is hungry, he may consume the carcass, but hunger is usually not the motivation. However, female bears instinctively know that their cubs are in danger. So she will defend her cubs if she is nearby. Sometimes she will be separated from her cubs. That is when the cubs are in the greatest danger. Many of the attacks by bears on humans happen when humans surprised a mother bear with cubs, and the female will then attack because she has no chance to get away with her cubs from the encounter. A female bear will generally make a detour with her cubs if she sees a male ahead, but she will risk her life to defend her cubs if she cannot avoid the male. Even though they are smaller, the females are more ferocious than males when defending cubs. Therefore a male will usually avoid a fight with her rather than risk injury, which could hamper his ability to hunt seals.