No mystery

Dolphins create a signature whistle for themselves that researchers believe is comparable to a human name, suggests a new study...
Dolphins in Australia do seem to produce more simple whistles, while Florida dolphin whistles appear to be more modulated," she said. "Right now, we don’t know why that happens."

- From the Discovery Channel.

No idea? I've got a pretty good idea, mayyyte. It's because Australian dolphins are simple blokes and blokesses who minimise the number of syllables so as to stop unruly sea-flies can't get into their mouths. Yepo. That's it.