Whales live in the ocean. They do not have homes. Their home is the ocean. If the ocean becomes too polluted for the whales to live in (the Gulf of Mexico for example), they will just have to swim somewhere else to live.
Because they are both blue. Maybe so they can blend in and because blue oceans are big Because they are whales and are meant to live in the ocean, just like humpback whales or any other whale lives in the ocean.