National Geographic : 1979 Jan
Humpback whales pass Bermuda each spring on their way north from southern calving grounds near Puerto Rico. During this period the humpbacks fill the ocean with complex and beautiful sounds. Many hours of these sounds were recorded and later analyzed with the help of a friend, Scott McVay, at Princeton University. The analysis showed that humpback sounds are in fact long songs. I use the term song not in a sense of beauty, although humpback sounds are indeed beautiful. By song I mean a regular sequence of repeated sounds such as the calls made by birds, frogs, and crickets. Humpbacks Change Their Tune Most birdsongs are high pitched and last only a few seconds, while humpback songs vary widely in pitch and last between six and thirty minutes. Yet if you record a whale song and then speed it up about 14 times the normal rate, it sounds amazingly like the song of a bird. In the second selection on side one of the detachable sound sheet included with this article (pages 24A and 24B),* you will hear that striking similarity. When you go out to listen to a humpback sing, you may hear a whale soloist, or you may hear seeming duets, trios, or even choruses of dozens of interweaving voices. Each of those whales is singing the same song, yet none is actually in unison with the others-each is marching to its own drum mer, so to speak. The fact that whales in Bermuda waters are singing the same song at any given mo ment is not surprising when you think of how similar two robins or two cardinals sound. But if you collect humpback songs for many years and compare each yearly recording with the songs of earlier years, something astonishing comes to light that sets these whales apart from all other ani mals: Humpback whales are constantly changing their songs. In other words, the whales don't just sing mechanically; rather, they compose as they go along, incorporating new elements into their old songs. We are aware of no other animal besides man in which this strange and complicated behavior occurs, and we have no idea of the reason behind it. If you listen to songs from two different years you will be astonished to hear how different they are. For example the songs we taped in 1964 and 1969-both of which can be heard on the enclosed sound sheet-are as different as Beethoven from the Beatles. By combining our own tapes with those of friends like Bermudian Frank Watlington, we now have a sample spanning twenty years in Bermuda. Katy and I have analyzed this data in detail. We find that the song has been con stantly changing with time. All the whales are singing the same song one year, but the next year they will all be singing a new song. The yearly differences are not ran dom, however. The songs of two consecu tive years are more alike than two that are separated by several years. Thus, the song appears to be evolving, but regardless of how complex the changes are, each whale apparently keeps pace with the others, so that every year the new song is the only one that a listener hears. Musical Talent May Be Inherited We have also recorded and analyzed four years of humpback songs from Hawaii, a major wintering area for humpbacks. Al though songs of the same year in Hawaii and Bermuda are different, it is intriguing that they obey the same laws of change, and have the same structure. Each song, for example, is composed of about six themes-passages with several identical or slowly changing phrases in them. Each phrase contains from two to five sounds. In any one song the themes always follow the same order, though one or more themes may be absent. The remaining ones are always given in pre dictable sequence. The whale populations of Hawaii and Bermuda are almost certainly not in con tact. Thus, the fact that the laws for compos ing the songs are the same in both places strongly suggests that the whales inherit a set of laws and then improvise within them. Whether these laws are transmitted from one generation to the next genetically or by learning remains to be seen. When Katy first *Longer samples of humpback whale songs can be heard on two albums produced by Capitol Records, Inc.: "Songs of the Humpback Whale" (SW-620), and "Deep Voices" (ST-11598). Artists' royalties go to the New York Zoological Society's Whale Fund.