Toadfish and midshipman fish use a variety of different sounds to attract mates and scare off rivals.

Now US researchers have found that the area of a fish's brain that drives vocalization is extremely primitive.

Writing in the journal Science, they say it suggests that the ability to communicate through sound emerged very early in the evolution of vertebrates.

Professor Bass told BBC News: "We identified where this pattern generator developed in the brains of these fishes, and then we looked at where it was in frogs, birds and primates."

The team discovered that the neural networks for vocalization were all situated in the same region.