Prehistoric fossil ear: Long before humans walked the Earth, dolphins already had super-hearing abilities, reveal Melbourne scientists

Melbourne scientists have made an interesting discovery. They have found out that the blipping, chirping and chattering noises made by dolphins to communicate with one another are at least 26 million years old. Their super-hearing abilities are prehistoric. They make these sounds to communicate, locate fast-swimming preys and navigate oceans.

The discovery was made possible by a prehistoric toothed whale's inner ear. Scans of the fossil ear showed remarkable similarities with modern dolphins. The discovery has been reported in the Royal Society journal Biology Letters and it sheds light on how these marine animals evolved. This also explains why our modern day dolphins are some of the world’s most social animals and intelligent creatures.

“Toothed whales are the only marine mammals to have developed the ability to sense their watery world by hearing and analysing such high-frequency sounds. This, in turn, allowed them to spread around the globe and become the most diverse of all marine mammals, with at least 73 known species,” said Travis Park, doctoral student at Museum Victoria and Monash University and lead researcher.

Dolphins belong to a family of toothed whales. Toothed whales include pilot whales and orcas. They hunt together using reflected sounds to find objects. They surround and trap schools of fish using a method called echolocation.

The fossil ear bone that the scientists used was from the Smithsonian Institution's National Museum of Natural History. The researchers produced high-resolution 3D images of the 26 million year old fossil ear using highly-advanced scanning technologies in Melbourne. The results were extraordinary. The researchers were stunned to find incredible similarities between the prehistoric toothed whale and modern echolocating dolphins.

Scientists for long have assumed toothed whales’ capability of producing high-frequency sounds. However, for the first time, researchers have been able to show that they were also capable of hearing such sounds.

Interestingly, much before humans walked on Earth, dolphins had already evolved their own complex communication and sensory system. This is a unique thing in the animal kingdom.