Bottlenose Dolphins (Tursiopstruncatus) naturally invent and exchange unique identity whistles that closely resemble human names.
After hearing a signature whistle a dolphin of the same species repeats the same whistle back, which acts as an introduction and allows the dolphins to address one another.
The research [HYPERLINK], led by Dr Vincent Janik from the University of St Andrews, focused on dolphins living in Sarasota Bay, Florida, and isolated the signature whistles from acoustic recordings of dolphin calls. The recordings were electronically modified before being played back to the animals through underwater loudspeakers: “It’s the equivalent of a computerized voice, where you can’t tell who is speaking by the voice alone,” Dr Janik told National Geographic.
The results help us understand how bottlenose dolphins engage in complex social interactions but they are not the only non-human animals to use vocal labeling. Studies have shown that some parrot species may use sounds to label individuals in their group.
The latest evidence seems to overturn a study published in 2001 [HYPERLINK] that suggested bottlenose dolphins share contact calls. Dr Janik criticized this work as it was based on captive dolphins and suggested that subjects in the wild have find it harder to stay in touch and so need more sophisticated communication.
Signature whistles may have developed to cope with the limitation on two important senses in dolphin – their limited vision in murky ocean waters, and their lack of smell. Dr Janik feels that increasing our understanding of vocal labeling, and how it has evolved in different groups of animals, will help us better understand how human communication developed.
IMAGE: Bas Kers (NL), Flickr