At just 2 millimeters long, the lesser water boatman (Micronecta scholtzi) doesn’t look like a powerhouse. Yet this tiny insect holds the title of one of the loudest animals on Earth, relative to its size.

Males produce their song by rubbing their penis against a ridge on their abdomen, a process called stridulation. The result is an underwater chirp that can reach about 99 decibels right at the source — the level of a passing train.

To our ears above the water, the sound comes across only as a faint tick, but underwater or with a sensitive microphone, it’s surprisingly loud. 

The song is part of courtship, helping males attract mates and warn rivals. So while most animals woo with feathers or colors, this minuscule bug sings underwater love songs powerful enough to be measured alongside giants.  Click here for more strange mating rituals.