Andrews shows how sperm whale vocal dialects evolve as they adopt new calls while still remembering the old. An international team of researchers studied vocal dialects in the endangered population of sperm whales in the Mediterranean Sea. They found that whales in the eastern Mediterranean had developed a new form of the vocal dialect used by animals in the western basin. The whales produced a distinct, faster form of the '3+1' coda type, but also produced the slower western form on some days, showing they were familiar with both dialects.