Scientists who conducted exploratory missions at the Mariana trench in fall of 2014 and spring of 2015 have recorded a mysterious sound that they called "Western Pacific Biotwang."

Five-Part Sound With Metallic Conclusion

The bizarre noises, which last up to 3.5 seconds, are characterized by sounds that range in frequencies with deep moans as low as 38 hertz and a metallic finale reaching as high as 8,000 hertz. The human ear can hear sounds in frequencies spanning between 20 and 20,000 Hz.

Researchers were initially baffled and confused over the cause of the five-part sound. It appears though that scientists finally have an idea where this mysterious calls come from.

Sound Likely Produced By A Species Of Baleen Whales

In a new study published in the Journal of the Acoustical Society of America, researchers suggested that the sounds are made by a baleen whale species. Baleen whales feed using the baleen plates in their mouth to filter small fish and krill from sea water.

Study researcher Sharon Nieukirk, from the Oregon State University, and colleagues think that the complex structure, metallic-sounding finale and frequencies of the call are produced by dwarf minke whales.

"It's very distinct, with all these crazy parts," Nieukirk said. "The low-frequency moaning part is typical of baleen whales, and it's that kind of twangy sound that makes it really unique. We don't find many new baleen whale calls."

Dwarf Minke Whales Produce "Star Wars" Like Sounds

Minke whales are baleen whales that produce a range of region specific calls. In the North Pacific, the marine animals produce "boings" while those in the North Atlantic produce low-frequency pulse trains. The sound made by dwarf minke whales on the Great Barrier Reef in Australia resembles that of the "Star Wars" sound effects.

Researchers said that several type of minke whales are present in the area in the Mariana Trench where the mysterious calls were heard but not much is known about these swimming mammals' behavior including their vocal behavior.

The researchers said that the Western Pacific Biotwang has many similarities to the "Star Wars" Call produced by minke whales in the northeast coast of Australia, which makes it reasonable to consider that the mysterious calls are produced by a minke whale.

"Aurally, the sound is quite unusual and most resembles the minke whale "Star Wars" call. It is likely this sound is biological and produced by a baleen whale," the researchers wrote in their study.