It’s not just whales that migrate thousands of miles across the seas. The songs they sing can cover long distances too. Several recent studies reveal more insight into the hauntingly beautiful and complex musical arrangements of male humpback whales, including just how far the repeating “themes” of their songs can travel.
Researchers have long known that humpbacks weave together repeating phrases, called themes, in their songs. Typically, a population shares these themes, though individuals may arrange them in different ways. Scientists then learned just over two decades ago that humpbacks on Australia’s west coast were sharing themes with others on the east coast. Further research revealed that songs from the east coast whales made it as far as French Polynesia, more than 3,700 miles away.
Then last year, marine biologists discovered those songs migrated nearly 5,000 miles further east over a three-year period, making it across the Pacific Ocean to the coast of South America. Early evidence suggests the songs could possibly travel even further, from the Ecuadorean coast to Brazil’s waters and then across the Atlantic to the South African coast, but a complete circumnavigation of the globe has not yet been confirmed.
The themes can undergo small changes as they pass from one population to the next, similar to the whispers from one ear to the next in a human game of “Telephone.” Researchers don’t entirely understand why one population might borrow another’s track or how the songs are shared. But they have learned in another study that humpbacks sing louder when the wind is loud—though not when noisy boats are around, even if the overall volume of the wind and boat noise are similar. Together, these findings reveal just how much more there is to learn about humpback’s mysterious songs.