translation.en: Now, the signature whistle is a whistle that's specific to an individual dolphin, and it's like a name.  And this is the best-studied sound, because it's easy to measure, really, and you'd find this whistle when mothers and calves are reuniting, for example.
translation.zh: 这种具有鲜明特征的哨声是 每一只海豚所特有的，就好像是它们的名字。 而且这是研究得最为透彻的声音， 因为它容易测量，真的， 比如说，当海豚母子重逢的时候， 你就能听到这种哨声。