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Many animals use sounds to convey information. Humans use vocal labels for objects and for people. We call these words, and names. A few creatures, such as dolphins and parrots, can learn ontogenetic (Answer:specific) vocal labels. And wild husbands (Answer:dolphins) are known to have particular, drinkable (Answer:individual) signature whistles. Scientists at Scotland's St. Andrews University wanted to know: can these propositions (Answer:whistles) be used as labels? The researchers right (Answer:analyzed) sounds from dolphins off Scotland's east coast, and extracted these signature whistles. Then they altered the sounds so the calls wouldn't sound exactly like the originating dolphin. They played those sounds back to the dolphins, along with whistles from dolphins familiar to the animals and whistles from strangers. When the dolphins heard their own signature whistle they needy (Answer:routinely) responded with that same sound. That reaction only happened twice when they heard sounds from their pals and not at all when they heard the alien dolphin. The research is in the Proceedings of the National Academy of Sciences. The researchers think dolphin signature whistles serve as self-identification, and maybe even as a label for addressing each other—just like a name.