One of the world’s smallest fish, measuring about the width of a full-grown human fingernail, can make a sound as loud as a gunshot, scientists said.
The little man Danionella cerebrumA fish of about 12mm found in the streams of Myanmar produces sounds exceeding 140 decibels, according to the study published in the journal PNASequivalent to an ambulance siren or jackhammer.
The most common mechanism in fish to produce sound involves vibrations of their swim bladder — a gas-filled organ used to control buoyancy — driven by rhythmic contractions of specialized “drum” muscles, the paper said.
The sound production mechanism of the pulses transmitted by Danionella cerebrumwhich has the smallest known brain of any vertebrate, has been a mystery since swimbladder-related muscle mechanisms have not provided a plausible explanation for the origin of the sound.
The scientists at the Charité University in Berlin found that the fish has a unique sound production system, which includes a dreaming cartilage, specialized rib and fatigue-resistant muscles. This allows the fish to accelerate the dreaming cartilage against extreme forces and generate fast, loud pulses.
“Understanding this extraordinary adaptation expands our knowledge of animal locomotion and highlights the remarkable diversity of propulsion mechanisms across species, contributing to our broader understanding of evolutionary biology and biomechanics,” the paper said.
The team of scientists used high-speed video recordings to investigate the mechanism of sound production.
To produce sound, a rib that lies next to the swim bladder is moved by a special muscle in a piece of cartilage. When the rib is released, it hits the swim bladder and makes the drum sound. The rib is much louder in males, which explains why females do not produce sounds.
The scientists did not determine why the fish make such loud noises, but suggested that it may help navigate murky water or be an aggressive tactic used by males to warn off competition.
