Something appears to be making a mysterious "pinging" noise on the sea floor of the Canadian Arctic. Inuit hunters in a remote community in Nunavut first reported the sound—also described as a "hum" or "beep"—complaining that it was scaring away marine animals in an area usually flush with them, reports the CBC.
Local lawmakers took up the case as callers to a radio talk show reported hearing it, too. The Canadian military sought to solve the mystery on Tuesday when it sent an aircraft to investigate, per the Guardian.
But "the air crew performed various multi-sensor searches in the area, including an acoustic search for 1.5 hours, without detecting any acoustic anomalies," a rep says.
The military plans no further investigation. While "we don't have a single clue" about the source of the noise, "we're still working on it," a member of the Nunavut Legislative Assembly said this week.
He added that the noise is "emanating from the sea floor." One of the more plausible theories is that mining companies are performing sonar surveys of the sea floor.
However, a company that has performed surveys in the area says it has no equipment in the water; officials add that no permits have been issued for construction, blasting, or hydrography work.
Greenpeace, meanwhile, has denied claims that it's purposefully broadcasting the noise to keep animals away from hunters. (Maybe it's the Alaska Ice Monster?)
This article originally appeared on Newser: There's a Mysterious Sound Coming From Canada's Arctic