Hope, the new polar bear, is obviously accustomed to the cold. On Monday, Hudson, Brookfield Zoo’s male polar bear, could be heard calling to Hope. The goal is for these two to mate, when they are ready. “There’s a very thoughtful introduction process between the male and female polar bears. When the timing is right we can open up the door and they can have a date,” said Tim Sullivan, curator of animal husbandry. He has worked at the zoo for 41 years.