Dolphins are not only social animals but also humans' friends. They are as intelligent as human children, but no one knew they could be so alike. According to a new research, they can even talk like humans.

A new study by the researchers of Aarhus University, Denmark, says that dolphins produce sounds in the same way as humans, they do not whistle, but talk to each other using a similar process of communication as humans.

The researcher from the Department of Biological Sciences studied the video clips, recorded in 1977, of a 12-year-old male bottlenose dolphin to find out how dolphins communicate.

The study found that humans and several other mammals, including dolphins produce sounds by tissue vibration analogous to the operation of vocal folds.

According to a Discovery News report, dolphins make sound by making connective tissue in the nose vibrate at the frequency it wishes to produce, adjusting the muscular tension and air flow over the tissue.

“It is the same way that we humans make sound with our vocal cords to speak,” said Peter Madsen, the lead author of the research.

We found that the dolphins don’t change pitch when producing sound in heliox, which means that its pitch is not defined by the size of its nasal air cavities, and hence that it is not whistling, Madsen said.

The study published in Royal Society Biology Letters says that apart from the whistle-like sound, dolphins also produce chirps and click trains, suggesting they engage in very complex and sophisticated social interactions.

Madsen explains that why dolphins produce sound at a higher pitch when they dive deeper: “It is because their air cavities get compressed due to the increasing ambient pressure.”

Madsen says all the toothed whales face the same problem during deep dives, as they have a similar nasal anatomy.

There is strong evidence that dolphins are able to see with sound, much like humans do, using ultrasound to see an unborn child in the mother's womb, as reported by Discovery News.

Very interestingly Madsen says, “The land-based ancestors of dolphins likely produced sounds as humans do, lost that skill when they went into water, and then evolved it again, but by using a completely different anatomy in their noses.”

The research reveals that if a person whistles after sucking in helium, the pitch of the tune will then be 1.74 times higher than if they whistle after breathing in just air.

For all the readers who wonder about what dolphins communicate and why they need to “talk,” Madsen explains — like every other animal, dolphins share information about their identity and stay connected when they dive or while travelling in shallow water.

He humorously puts it, “I believe that people around the world would love the opportunity to speak with a dolphin. And I feel certain that dolphins would love the chance to speak with us, if for no other reason than self-preservation.

It would be interesting to see the human-dolphin interaction, if in future humans evolve enough to understand dolphins' language.