Two more mysterious craters have appeared in Siberia, and while there is still no consensus among geologists as to what has caused them to form, some have suggested climate change could be to blame.

“It is not like this is the work of men, but also doesn't look like natural formation,” a source told the Siberian Times.

The large holes were found in one of the most remote regions of the world by reindeer herders, according to the Siberian Times. Earlier this month, a crater measuring more than 100 feet, or about 30 meters, in diameter and more than 600 feet deep was discovered on the Yamal Peninsula on the shores of the Arctic Ocean. Yamal means “End of the World” in the language of the peninsula’s indigenous people --a testament to the region’s remoteness. Video footage of the bizarre hole, which seemed to appear out of nowhere, quickly went viral, sparking interest among Internet audiences everywhere.

Herders encountered one of the newest craters near the site of the original one. It measured about 50 feet across, roughly half the size of the first crater.

The second of the newly found craters was discovered in the neighboring Taymyr Peninsula. It was much smaller than the other one with a diameter of about 15 feet, but its depth is estimated to be as much as 300 feet. The hole lies on a reindeer pasturing route and was described as being a perfect cone. The Siberian Times published photos of the craters in northern Russia, some of which can be seen here.

Several theories about the holes’ origin have emerged, some more credible than others. One of the early assumptions regarding the original crater was that a meteorite had created the massive chasm, but that suspicion was quickly dismissed when geologists found no evidence that an impact had taken place. Other origin theories include stray missiles, a very elaborate man-made prank or even alien invaders.

But geologists say more natural processes are probably at play and could have something to do with climate change. The theory goes something like this: As global temperatures continue rise, the Siberian permafrost -- the layer of frozen rock or sediment that rests just below the top layer of soil -- starts to melt, causing a release of methane gas under the earth. When enough methane has accumulated, an eruption occurs.

Marina Leibman, a leading Russian permafrost scientist who recently studied one of the craters, corroborates the methane gas theory and details how it works. In an interview with the New York Times, she said methane gas is released because of a warming mix of ice, water and soil, causing pressure to build that explosively pushes the soil up and out to create a hole. Leibman noted that this process is nothing more than the normal course by which lakes form in that region of the world.

The original video, shot from a helicopter and showing the first mysterious crater in Siberia, can be viewed here: