Mima mounds at Oregon’s Zumwalt Prairie, USA

© Michael Durham/Minden Picture

Little hills on the prairie. Mysterious Mima mounds

Collections of these bubble wrap-like hills bulging out of the ground are found on every continent except Antarctica, but they are most common in landscapes throughout North America. Their origin isn’t always clear, with theories ranging from seismic activity to gophers – and even just an accumulation of sediment. The Mima mounds (also known as prairie mounds, hogwallow mounds or even pimple mounds) on our homepage today are part of Oregon’s Zumwalt Prairie, a unique landscape in the US state of Oregon in the Pacific Northwest. Encompassing some 330,000 acres, the grassland area is home to a remarkable number of hawks, eagles and other wildlife.