Study: fish grunts, hums foundation of human speech

BEIJING, July 21 (Xinhuanet5) -- Chirping fish, barking dogs and all the other sounds that issue from an animal's mouth are the products of the neural circuitry likely laid down hundreds of millions of years ago with the hums and grunts of fish, according to a new study.

"Fish have all the same parts of the brain that you do," explained study leader Andrew Bass of Cornell University.

His team traced the development of the connection from the midshipman fish's vocal muscles to a cluster of neurons located in a compartment between the back of its brain and the front of its spinal cord. The same part of the brain in more complex vertebrates, such as humans, has a similar function, indicating that it was highly selected for during the course of evolution.

The fish that Bass studied are interesting in their own right.

After building a nest for his potential partner, the male midshipman fish calls to nearby females by contracting his swim bladder, the air-filled sac fish use to maintain buoyancy. The sound is a hum, something like a long-winded foghorn. Female midshipman only approach a male's nest if he makes this call.

During midsipman mating season, houseboat owners in San Francisco Bay have complained that their homes vibrate from the humming, which sound like a high-speed motor running underwater.

By better understanding how these fish hear, the study offers new avenues to explore the causes of human deafness, the researchers say.

(Agencies)