For over two decades, marine biologists have been listening to the songs from a whale that resides in the North Pacific. However, they have never heard a fellow mammal responding. That's because, unlike most whales that croon at a frequency of 15-20 hertz, this one sings at high pitched 52 hertz. As a result, this poor animal has never had a friend and, therefore, become known as the "world's loneliest whale!"