This was actually a gift for a good friend of mine who is an expert on whales. These mammals are among the largest animals existing, the blue whale, in fact, is the largest animal on earth. As I have been told, the flukes of each whale are quite unique, thus being a very important characteristic of each individual. Especially in Norway, it is possible to observe them in their natural environment on whalesafaris.

For more general information, see the Wikipedia-entry on whales.