How do dolphins say "Hi"

Dolphins use signature whistles to greet their own kind akin to humans saying "Hi" to others. These whistles are evidently observed for decades to dolphins in captivity. But do they use the same whistles when one meets another in the ocean?

New research revealed that dolphins don't just make use of their whistle to greet another pod of dolphins in the ocean but also their way of making a friendly contact of saying, can we be friends? Researcher Janik of the University of St. Andrews in Scotland, together with his friends conducted their research at St. Andrews Bay using special array of microphones to follow bottlenose dolphin pods. When a pod of dolphins joined another pod, researchers found out that it is preceded by a whistle and will be seconded by another dolphin. If they just passed by each pod and didn't join, these "Hello" whistles are absent.

Dolphin calls are very important as they are one of the few animals that can make new sounds. Some primates can verify who-is-who by the sound of their voices, but they don't have signature calls unlike dolphins. These signature calls are dolphins' version of a personalized calling card. Cool, yeah?