Motherhood brings a lot of questions and insecurities. After all, it is an immense responsibility caring for a life. Despite all the self-doubt, our inner animal instinct to love and protect our cubs kicks in very quickly. The animal kingdom is filled with mothers doing everything for their offsprings to survive and thrive in the wild. From koala bears carrying their joeys in their pouch for the first six months of their lives to the mama polar bear who fasts up to eight months while nursing her cubs. Here are some heartwarming photos of some very cool and hardworking mommies.