How are you like your animal counterpart? You have a cell phone -- humpback whales have fins. You text your besties -- these guys use their "thumbs" too. To avoid losing track of each other, the mama and its calf keep in contact by slapping the surface of the water. Together, they travel 4,000 miles from the tropics to the waters off Antarctica in search of food. But global warming affects where these amazing creatures chow down. Learn more about them by seeing Earth, in theatres April 22.