Early scientists have made us believe that dolphins are the most intelligent creatures next to humans but a new study shows that these sea creatures are not even better than other animals.

Justin Gregg, a zoologist and author of the book titled Are Dolphins Really Smart?, released this month suggests that humans have been deceived by the dolphins 'permanent smile' which early scientists perceived to be a near-human quality.

"Dolphins are fascinating in their own right, but in terms of intelligence they are nowhere near as special as they have been portrayed," Gregg wrote.

Gregg believes that the dolphin's ability to mingle and socialize with large groups, empathize, and communicate with other dolphins are not special traits. Such abilities could also be observed on other creatures such as chickens, pigs, and bears.

U.S neurologist John Lilly was the first to say that dolphins are intelligent during the 1950s citing these animal has a large brain and complex vocalization. Gregg believes that Lilly came up with the idea to protect these animals from being murdered because sophisticated animals would usually receive better rights and protection.

"Lilly transformed what was regarded as an odd air-breathing fish into an animal so sophisticated it deserves the same constitutional protection as humans," Gregg told the Australian.

"Dolphin communication does not seem to be that special. They do have a unique signature whistle, and it's possible they could use this to communicate, but they don't seem to have alarm calls or food calls - in that respect they are less sophisticated than chickens."

Aside from disproving the intelligence level of the dolphins, Gregg also wants to disprove our belief that these creatures are "peace-loving."

He cited different instances such as a record from the Sea Mammal Research Unit at St Andrews University in Scotland wherein dolphins were seen killing porpoises near the harbor. Another is a report from Western Australia's Shark Bay wherein a group of male dolphins were seen isolating females and forcing them to mate.

Dolphins have also often been portrayed as peace-loving creatures living in harmonious societies. New research paints a different picture.

Scientists at the Sea Mammal Research Unit at St Andrews University in Scotland have recorded how bottlenose dolphins often kill the smaller harbour porpoises they encounter, although never to eat. The leader of one particularly aggressive pod has even been dubbed Jack the Flipper.

In Western Australia's Shark Bay, gangs of male dolphins have been observed working together to isolate females and forcibly mate with them.