定义：In the really harsh natural environment, some animals will use dormancy to protect themselves from the nature. In a word, they will avoid exposure to certain elements in the environment and use slow metabolism to preserve energy.
听力：Professor used an example of the lungfish to demonstrate the term, lungfish lives in the shallow lakes that faces the possible consequences of drying up. If the lake dries up, then the lungfish is cooked, so they
will explore certain method to prevent that from happening. So basically what the lungfish do is to dig a hole through the mud at the bottom of the lake, its body will be curled up and berried in the mud, so the covered
mud could be a proactive coat for the lungfish that keeps them away from the heat and also keep the moisture inside the body. The lungfish will keep the body still and breathe really slow, the heart beat is slowing down
as well. Usually the lungfish relies on eating crabs and small fish to survive but since it lives in the shelter, it doesn’t need to eat anything at all. They can survive in this shelter for months, or even years until the lake