Grunt, growl and channel your inner fish

	Late stage midshipman larvae (about 30 days old and 20 mm length) attached to a rocky substrate. Click here for more information.

Scowls perpetually, communicates with grunts and growls, spends lots of effort attracting mates and defending territory -- no, it's not a human teenager, it's the toadfish, researchers report in the July 17 issue of Science. These noisy creatures, and their close relatives the midshipman fish, share the ability to vocalize with many other animals, from birds, to frogs, to humans. A new study of these fish suggests that the brain machinery that drives vocalization is extremely primitive, having evolved more than 400 million years ago, with the evolution of bony fish. Toadfish use their swim bladder and attached muscles, which are among the fastest known for vertebrates, to make a variety of sounds to attract mates and defend territories. These fish have a brain circuit of rhythmically firing neurons that determines the contraction rate of the vocal muscles and, in turn, the pitch and duration of their calls. The researchers mapped this neuronal network in larval fish and found that it develops across a specific region that includes the base of the hindbrain and the upper spinal cord. This pattern of neuronal development is similar to those of other vocalizing vertebrates, suggesting that the brain circuitry driving vocalization may have its origins far back in the evolution of bony vertebrates. Other aspects of the vocal systems, namely the particular muscles and vocal organs (fish swim bladder, bird syrinx, mammalian/human larynx), seem to have evolved independently in different lineages. A related Perspective discusses these findings.

ARTICLE #23: "Evolutionary Origins for Social Vocalization in a Vertebrate Hindbrain-Spinal Compartment," by A.H. Bass at Cornell University in Ithaca, NY; E.H. Gilland at Howard University College of Medicine in Washington, DC; R. Baker at New York University Medical Center in New York, NY; A.H. Bass; E.H. Gilland; R. Baker at Marine Biological Laboratory in Woods Hole, MA; A.H. Bass at University of California in Bodega Bay, CA.