They've puzzled naturalists for decades, but there may finally be an explanation for what causes the expansive, mysterious fields of Mima mounds.
The Mima mounds are circular hillocks that occur around the world (but mostly in North America), sometimes measuring as tall as seven feet high and 160 feet wide. Groups of Mima mounds can sometimes be found clumped together over areas kilometres wide, with millions of the mounds in close proximity giving an other-worldly look to areas they are found in.
But, rather than inter-galactic beings acting as the Mima mounds' architects, it appears burrowing rodents of the gopher family are the cause of the phenomenon.
Researchers at the San Jose State University used a computer simulation program to replicate how the rodents burrow, shifting small amounts of earth upwards in areas prone to watterlogging. Over hundreds of years, generations of gophers repeat the movements, leading to the formation of the mounds. As ever, it's a surprisingly obvious answer to an age-old question, now proved once and for all by science.
We reached out to the gopher community for comment, and recieved this response: