Graceful, powerful, and awesome in size, whales are breathtaking animals. About 50 humans could fit on a blue whale's tongue. These mammals roam the open seas searching for enough food to sustain their gigantic bodies. Whales have been a source of food and fuel for thousands of years, but we rely upon them so much that their survival has become a concern. Even with strict anti-whaling laws on many waters, some species of whales are in serious danger...