What do tigers come to represent in the novel, The Girl Who Drank the Moon?

Sister Ignatia is described as being very much like a tiger, and the tiger descriptions in this story come to symbolize ruthlessness. Tigers are predators. They hunt for food and they are considered to the strongest animals in their ecosystems. They are fierce and strong and relentless about their territory. In their natural environment, tigers will do anything to survive and they acquire survival skills which will help them remain in power.