A new study examining thousands of recordings of sperm whale vocalizations in the Mediterranean Sea finds that whales in different regions show distinct click-pattern “dialects.” Sperm whales communicate using sequences of short clicks known as codas, and the rhythmic pattern of these clicks can vary among social groups. Researchers report that matriarchal groups in the eastern and western Mediterranean produce different vocal patterns, suggesting that geographically separated groups are developing their own dialects. One account describes evidence consistent with the population forming two groups with different dialects, rather than a single uniform pattern across the sea. The study also characterizes the dialects as being used to help maintain social structure within matriarchal groupings. Overall, the findings draw an analogy to human languages by showing that communication systems can change between groups over time, potentially reflecting limited mixing and local development. The study is published in the Proceedings of the Royal Society B, and the researchers use the audio recordings to compare vocalizations across regions.