Danionella cerebrum is a popular species for scientific study because it is transparent, meaning scientists can easily observe its brain and internal organs.
Verity Cook, the lead author of the research and a PhD student at the university, told the BBC: “People are just walking around fish tanks, and they hear these sounds, and wonder if where did they come from?
“It comes from the fish itself. And it’s unusual because they’re so small and so noisy.”
Experts believe that the sounds are generated by the fish as a means of communication and to find each other – the species is native to Myanmar, where it lives in dark, muddy waterways in a mountain range.
Or it may have something to do with mating behavior – only the males make the sound.
The small fish makes the noise by contracting its muscles and pulling on a rib which creates tension on a strip of cartilage. When that cartilage is released, it hits the swim bladder, the gas-filled organ that all fish have, which makes the drumming sound.
‘Fast, strong pulse’
Fish muscles are particularly resilient to fatigue, allowing frequent beats against the swim bladder.
“We found that it possesses a unique sound production apparatus, involving drumming cartilage, specialized rib and fatigue-resistant muscle, which allows the fish to accelerate the drumming cartilage to extreme forces and generate a fast and powerful pulse,” said scientists with their findings. , published in the scientific journal Proceedings of the National Academy of Sciences.
“Such amplitude is highly unusual for an animal of this size.”
Scientists measured the volume using underwater microphones.
There are noisier species of fish known to science, but they are all larger than the pipsqueak Danionella cerebrum.
“In terms of communication signals, I can’t find another animal this size that makes sounds this loud,” Ms Cook said.
The little fish has another claim to fame – it has the smallest known brain of any vertebrate in the world.
