Dolphins call each other by name: This is according to a new study by scientist. Researchers revealed that the marine mammals use a unique whistle to identity each other.

These dolphins call each other by name using these whistles because when a dolphin hears a whistle sound directed at them, they respond. A team from the University of St Andrews in Scotland found that when the dolphins hear their own specific call played back to them, they would respond.

"We played signature whistles of animals in the group, we also played other whistles in their repertoire and then signature whistles of different populations - animals they had never seen in their lives," Dr. Janik of the university's Sea Mammal Research Unit told BBC about the dolphins that call each other by name.

"[Dolphins] live in this three-dimensional environment, off-shore 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."

It has been previous reported that dolphins would adopt these sounds and those in their group would learn the sounds and use them as well. This study in particular is the first of the dolphins using specific whistles for specific dolphins, thus becoming their names.

After the signature whistles, they played the callbacks using underwater speakers.

"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," Dr. Janik told BBC.

Dr. Janik said this could be a find in how the evolution of communication with humans came about.