Dolphins can identify with and respond to each other using a unique whistle, according to research published in the Proceedings of the National Academy of Sciences (PNAS) .
The research, published in part on the PNAS website, demonstrates that “Bottlenose dolphins can use learned vocal labels to address each other.” Vocal labelling occurs when an animal uses a specific and consistent acoustic signal to interact with an object or class of objects.
This forms part of the foundation of human language, but is not common among animals.
However, a team of researchers from the University of St Andrews, Scotland, have found that dolphins respond when they hear their own call played back to them. In the PNAS report, it is stated that bottlenose dolphins are particularly interesting “because they are capable of vocal production learning and can learn to use arbitrary signals to report the presence or absence of objects.”
Dr Vincent Janik, who works at the university’s Sea Mammal Research Unit, attributes dolphins’ need for an effective communication system to their habitat:
“(Dolphins) live in this three-dimensional environment, offshore, without any kind of landmarks and they need to stay together as a group.”
“These animals live in an environment where they need a very efficient system to stay in touch,” he added.
Research had already been done into the similarity between dolphins’ use of distinct whistles and humans’ use of names. However, this is the first study into dolphins responding to their own “names”. Janik believes that a greater understanding of the evolution of this skill in animals could provide further insight into the development of communication among humans.
A part of the research involved recording a school of bottlenose dolphins and capturing each animal’s individual sound. These signature calls were then played back to the dolphins using underwater speakers.
Janik and his team have discovered that dolphins act in a similar way to humans, and answer when they hear their own name: a skill that must prove helpful when the group is trying to stay together in their vast environment:
“Most of the time they can’t see each other, they can’t use smell underwater, which is a very important sense in mammals for recognition, and they also don’t tend to hang out in one spot, so they don’t have nests or burrows that they return to,” Janik observed.
Although researchers at St Andrews believe that this is the first time communication such as this has been seen in an animal, similar analysis involving vocal labelling among parrots has also been carried out.