Mima mounds

Mima mounds are like a bunch of little hills that are found in some areas of the Earth. Imagine you're playing with some sand and you start making little piles. Now imagine those piles are in a big field and they're all different sizes, but they're not piles of sand - they're made of dirt and grass. That's what a mima mound looks like!

Scientists have been trying to figure out how these mounds formed for a really long time. Some people used to think that animals like moles or gophers made them by digging tunnels under the ground. But now it seems like the mima mounds were probably made by the soil itself!

When you dig down into the ground, you can find layers of soil that are different colors and textures. Some of the soil is harder and can hold its shape better than others. Over a long, long time, changes in temperature and moisture probably caused the soil to expand or contract, which made the mounds slowly form on their own.

It's still a mystery why mima mounds are only found in some places, and not everywhere on Earth. But if you ever see one, you'll know that it's a little hill made by the ground itself!