MYSTERY OF WASHINGTON STATE'S MIMA MOUNDS MAY BE SOLVED
December 09, 2013
(LITTLE ROCK, WA) -- If you travel to the Mima Mounds Natural Area Preserve in our state, near the community of Little Rock in Southwest Washington you will see the strange formations which for centuries have baffled scientists and layman alike.
Dr. Victor (Vic) Scheffer looks out across the 445-acre Mima Mounds Natural Area Preserve in Wash. State. Photo courtesy Nature Conservancy. CLICK TO ENLARGE
A typical Mima Mound. CLICK TO ENLARGE
More of the Mima Mounds in Thurston County. CLICK TO ENLARGE
Some have speculated the mounds of dirt and gravel - which are named after the Mima Prairie in Thurston County - and are circular to oval and domelike and measuring up to 2m (7ft) in height and 50m (160ft) in diameter, are the work of extra terrestrial beings who visited earth eons ago.
Some have speculated they are ancient Native American burial mounds, or they were caused by earthquakes or glaciers.
These geological anomalies rise gently from the earth and cover acres of land. In density they range from several to more than 50 mounds per hectare.
You'll also find the strange mounds in places in Idaho and Oregon and there are similar mounds to be found in states in three major regions west of the Mississippi River where they are known as "hogwallow mounds".
In some areas, these mounds can number in the millions, stretching for many miles across the land.
And now the mystery of who made the strange mounds may finally have been solved.
New research, to be presented during a lecture at 1:40 pm Monday Dec. 9 at the American Geophysical Union Fall Meeting in San Francisco suggests that tiny burrowing animals, such as gophers and prairie dogs are the builders of the mounds -- and they takes hundreds of years and generations of animals to make them.
The lead researcher Dr. Manny Gabet, of San Jose State University, told the BBC News he is now certain that gophers have created the mysterious mounds.
Using a computer program, the researchers analyzed how the rodents move soil as they burrow. They found that in areas prone to water-logging, the gophers gradually shift tiny amounts of earth upwards to try to stay dry.
And over hundreds of years, as many generations of gophers repeat this process over and over, these minute piles of soil grow into the large structures we see today.
Mima Mounds in the U.S. tend to be infested by gophers.
Dr. Gabet told the BBC he developed 'digital gophers' and had them behave like they do in real life, and to his surprise Mima Mounds started to form in this virtual landscape.
"The [computer] model results look so similar to the mounds in every way - not just the dimensions, but also the way they are packed and how many you get per area," said Gabet.
He added that the computer modeling using the digital gophers, "Replicates the real-life situation almost perfectly."
But there is a catch. Gophers are only found in America, while Mima Mounds are found in every continent except in Antarctica.
Dr. Gabet thinks other subterranean mammals, such as moles are at work in those places.
"A good place to start would be to dig into these mounds [in other countries] and see what kind of critters are living inside of them," he told the BBC.