Squeaker Catfish, Young and Old, Squeak and Listen

Squeaker catfish of all ages communicate with each other by, you guessed it, squeaking, according to a new study in the journal BMC Biology. Previously it was thought that young fish had under-developed hearing organs and could not perceive sounds made by older fish.

(Synodontis schoutedeni, a squeaker catfish)

The findings add to the growing body of evidence that fish have complex communication systems and aren't always the strong, silent types.

For the study, researchers studied the catfish Synodontis schoutedeni. This species rubs the spines of its pectoral fins into grooves on its shoulder, thus creating the squeak sound.

By placing the fish in a combined fish tank and sound-proof chamber, the scientists were not only able to measure the produced sounds, but also how well each fish heard them. Young and old squeaker catfish were tested.

"This study is the first to demonstrate that absolute hearing sensitivity changes as catfish grow up," said the University of Vienna's Walter Lechner.

Measuring the hearing and sound production of a squeaker catfish

He added, "This contrasts with prior studies on the closely related goldfish and zebrafish, in which no such change could be observed. Furthermore, S. schoutedeni can detect sounds at all stages of development, again contrasting with previous findings."

Lechner and his team believe that catfish use the squeaking sounds mostly to show their stuff during competitions and to warn each other about predators. 

As the catfish grow, they squeak longer and louder.

"We found that as fish get larger, the sounds they make increase in level and duration," explained Lechner. "Hearing sensitivities increase with growth, but even the youngest fish are capable of communicating over short distances."

In other news, please don't forget to check out Animal Planet's Jane Goodall page. There you'll find cool chimp videos and a chance to nominate your own "Green Hero," a person who has made your community a better, more environmentally friendly, place to live.