Although the researchers say these songs don't meet the linguistic rigor necessary for a true language, this is the first evidence that animals other than humans use a hierarchical structure of communication. Whales have also been found to sing in dialects.
During mating season, which lasts six months, all humpback males sing the same song to woo the ladies. Over time, the group's song becomes progressively more complex, although researchers don't know quite why.
Presumably, as one whale finds mating success by tinkering with the song style, the rest of the guys imitate it to better their chances, said study co-author Ryuji Suzuki, a Howard Hughes Medical Institute predoctoral fellow.