 And what's hard to hear by ear, and one of the reasons why this is neat in our new study, is that they're varying the duration of those rhythms. Even if they're making the same click, click, click, click, click, they're changing how long that sound is, and the whale that's speaking with them is matching that duration very accurately. So all of these features suggest that this language, as you have said, is more complex maybe than we might have thought and can be used to express a wider variety of things.