There are eleven populations of humpbacks around the world, each covering their own ocean-sized territory. These populations each boast not only their own dialect of song, but also their own anthem of sorts — each whale singing the same sequence of the same sounds. But week-to-week, month-to-month, and year-to-year this song evolves, as the whales collectively create new phrases and patterns, totally in sync.
Excerpt from an article on Medium.com, Whale Song Explained, by David Rothenberg