Many birds and mammals can communicate with each other using sounds and 'body-language' to enable them to get along.

 

Birds can make a call which means 'danger' or 'I'm looking for a mate'. They can't say 'Pass me that nut' or 'I think it might rain.' In other words they can't string ideas together using grammar and syntax.

 

We know that dolphins use signature whistles similar to human names, but can they share ideas as humans do?

 

The short answer is that we still don't know. Dolphins use visual signals like many other animals. For example to show frustration, threat, or anger, dolphins may vigorously bob their head, swim in an an S-shape or slap the surface of the water with their fins.

 

Like humans, dolphins are highly social animals and need to communicate anything from how they feel to where to find dinner. Like humans, dolphins only spend a small part of the day feeding, and much of their time socialising. Like humans, dolphins have big brains compared to their body size.

 

On the other hand, we probably shouldn't expect dolphins to speak as if they were just humans with flippers. Dolphins have abilities that we don't; for example the ability to use sonar. It would be silly for dolphins to think we're useless just because don't have the same ability.

 

In 1965 a scientist called John Lilly carried out an experiment in which a young assistant called Margaret Howe lived for 10 weeks in a flooded house with a bottlenosed dolphin called Peter to see if she could teach him to use human speech. Peter was very keen to imitate Margaret and the words that she was saying, but could not be said to have learned English. 

 

In 1984 Louis Herman trained two bottlenose dolphins in Hawai called Ake and Phoenix to understand gesture symbols and whistle symbols to understand simple sentences. 

 

Ake and Pheonix learned the difference between Surfboard-Swimmer-Fetch to bring the swimmer to the surfboard and  and Swimmer-Surfboard-Fetch to bring the surfboard to the swimmer.

 

The dolphins made sense of new sets of instructions even when they were confusing. Ake and Phoenix both learned about 30 words and responded correctly to instructions about 80% of the time.

 

Later scientists have focused on trying to understand the sounds that dolphins make to each other, but that has proved more difficult. There is a lot about dolphins that humans have yet to figure out, and whether they use 'language' to speak to each other is one of them.

 

If you think about it, if you meet someone who speaks another language to you, you can still communicate with them pretty well by using gesture and facial expressions. It could be that dolphins are like a Frenchman and a Russian getting on with each other even though they don't have 'language' in common.

 

On the other hand it may be that we just haven't figured out dolphin language yet because it's so different to our own.

 

See also the Dolphin Communication Project.