SharpBrains

A dolphin made a lot of blog-buzz this Monday, being the 14th pink bottlenose dolphin described in history. Bottlenoses are quite special; did you know that they are one of a few species in addition to humans that is observed to use tools? Their relative brain size isn't that different from humans either.

The Bottlenose dolphins are actually the most common and well known of all dolphins. Not too long ago, scientists used to believe that "tool use" was one of the characteristics that set humans apart from all other animals. Later, scientists discovered the use of tools by great apes. More recently, bottlenose dolphins in Australia's Shark bay are observed to carry sea sponges on their beaks for protection when searching for food in the sandy sea bottom.

What is really fascinating is that the dolphins probably learned the trick from their moms rather than inheriting a sponge-shuttling gene. Dr. Michael Krutzen at the University of Zürich which first discovered the phenomena, writes in his Proceedings of the National Academy of Sciences publication that dolphins' sponge use is a case of cultural transmission-the passing along of a learned behaviour.

So what can we learn about human cognition by studying dolphins? Much research has been done on Cetacean intelligence – the cognition and brain functions of whales and dolphins. In addition to tool use, they can recognize themselves in mirrors and understand symbol-based communication systems and abstract concepts.

The extent of their advanced functions seems to be correlated to their large brain size. Experts have long known that dolphins have exceptionally large brains relative to their body size. As a matter of fact, dolphin brains are one of Nature's largest in terms of the Encephalization Quotient (EQ). EQ is the ratio of brain to body mass. Humans are the brainiest (largest EQ) of all creatures.

What the dolphin has taught us is that the EQ difference between humans (EQ 6.5-7.5) and dolphins (EQ 4-5) is not enough to describe the human brain’s more sophisticated capacity for abstract thinking and problem-solving. There must be more than just a difference in brain size.

Researchers have found that the different types of brain cells (not just the neurons), their internal relationships and to what extent the various brain regions are evolved must be taken into account. For example, humans distinguish themselves by the more evolved neocortex and through a different cellular distribution and arrangement than dolphins.

So size matters, but it is just a small piece of the puzzle. Researchers continue the search for the connection between brain and mind. As we keep demystifying the brain, it’s again time to think about what makes us humans. The dolphin story has showed that watching our animal friends can help us learn more.

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