Researchers from Cornell University have discovered that parrots in the wild pass on learned vocal signatures to their offspring, much like in human society. This suggests that every parrot has a name of its own. They also found that the parents made contact calls before the nestlings could make their own calls and that the offspring imitated them as they grew older. This phenomenon also occurred with nestlings reared by foster parents, proving that it is a learned social behavior as opposed to a genetic feature. So far, only humans, dolphins, and parrots have been shown to mimic the signatures of others throughout their lives.