[LINK] Two links on dolphins and their apparent use of names

[rfmcdonald]

(Is it me, or is it starting to look like dolphins, at least, should be counted as people?

First comes the news from Discovery's Jennifer Viegas.

Earlier research found that bottlenose dolphins name themselves, with dolphins having a “signature whistle” that encodes other information. It would be somewhat like a human shouting, “Hey everybody! I’m an adult healthy male named George, and I mean you no harm!”

The new finding is that bottlenose dolphins also say the names of certain other dolphins.

“Animals produced copies when they were separated from a close associate and this supports our belief that dolphins copy another animal’s signature whistle when they want to reunite with that specific individual,” lead author Stephanie King of the University of St. Andrews Sea Mammal Research Unit told Discovery News.

King and her colleagues collected acoustic data from wild bottlenose dolphins around Sarasota Bay, Fla., from 1984 to 2009. The researchers also intensely studied four captive adult male dolphins housed at The Seas Aquarium, also in Florida.

The captive males are adults that keepers named Calvin, Khyber, Malabar and Ranier.

These bottlenose dolphins, however, as well as all of the wild ones, developed their own signature whistles that serve as names in interactions with other dolphins.

Wired's Brandon Keim has a more extended analysis of the research.

To investigate these possibilities, King and Janik’s team analyzed recordings made over several decades by the Sarasota Dolphin Research Program, a Florida-based monitoring project in which pairs of dolphins are captured and held in separate nets for a few hours as researchers photograph and study them.

During the captures, the dolphins can’t see each other, but can hear each other and continue to communicate. In their analysis, King and Janik showed that some of the communications are copies of captured compatriots’ signature whistles — and, crucially, that the dolphins most likely to make these were mothers and calves or closely allied males.

They seemed to be using the whistles to keep in touch with the dolphins they knew best, just as two friends might if suddenly and unexpectedly separated while walking down a street. Moreover, copying wasn’t exact, but involved modulations at the beginning and end of each call, perhaps allowing dolphins to communicate additional information, such as the copier’s own identity.

That possibility hints at what linguists call referential communication with learned signals, or the use of learned rather than instinctively understood sounds to mentally represent other objects and individuals. As of now, only humans are known to do this naturally.

“We learn language and refer to objects. This has been shown with captive dolphins and captive gray parrots, but hasn’t been seen in the natural communication system of any species,” said King. “We’re not saying that this is what they’re doing, but we’re definitely suggesting that we should look into it.”

Robert Barton, a cognitive scientist at England’s Durham University who has previously chafed at the notion that dolphin vocal signatures could be considered names, cautioned against reading too much into their communications. He noted that dolphins captured in the Sarasota project do copy each other’s signatures, but only infrequently.

King and Janik see this as supporting an identity-rich meaning for the copied whistles, which seem to be used specifically in communication with select individuals. From Barton’s perspective, other interpretations are equally possible, including a very limited importance for copying.