For years, scientists have been perplexed by a low-frequency humming sound made by deep-sea marine life at certain times of day. New research out of the University of California reveals that it could be the creatures’ way of communicating during feeding time — or they could be farting.
According to Discovery, the question of why deep-sea creatures emit a low-frequency humming sound at certain times of night has long confounded scientists.
New high-sensitivity audio recordings have revealed that the noise is being caused by deep-sea animals such as fish, jellies, shrimp, and squid which live in the ocean’s mesopelagic zone, a region between 660 and 3300 feet beneath the surface.
The mesopelagic zone is a dark place. It’s so low that the sun barely shines, so food isn’t necessarily plentiful. As a result, the creatures in this zone need to venture to the surface in order to eat. However, they wait until the cover of night and the safety of night before they do it.
When they do begin to head up to the surface, the low hum, which comes in at about 3 to 6 decibels louder than the ocean’s background noise, begins.
“It’s not that loud,” said San Diego biologist Simone Baumann-Pickering. “It sounds like buzzing or humming, and it goes on for an or two hours, depending on the day. ”
While it’s thought that this sound might be the animals’ way of communicating to one another during the feeding time, the answer as to why they make this sound is still up in the air. In fact, one theory is that the fish are passing gas at such a rate that adds up to make the noise.
“It’s known that some fish are considered to be farting,” Baumann-Pickering said in an interview with NPR.