A 4-inch tower of mud balls with a hole in the center in a lawn is most commonly made by a burrowing crayfish. 🦞
Likely culprit: Crayfish (often called a “crawfish”)
These freshwater crustaceans dig deep burrows in wet soil or lawns with high groundwater. As they dig, they push mud up to the surface and stack it around the opening, forming what’s called a “crayfish chimney.”
What it looks like:
- A small tower or chimney of mud pellets
- Usually 2–6 inches tall
- Round hole in the middle (the entrance to the burrow)
- Often appears after rain or in moist areas of the yard
Why they build it
- The chimney helps keep water and debris from falling into the burrow.
- The burrow below can go 1–3 feet deep, sometimes reaching groundwater.
Are they harmful?
Usually not dangerous, but they can:
- Make the lawn bumpy or muddy
- Create multiple small chimneys in wet areas
What you can do
- Reduce excess moisture (improve drainage if the lawn stays wet)
- Flatten the chimney with a rake if you don’t want it there
- If many appear, it usually means the soil stays very damp
✅ Good news: they’re actually beneficial for soil aeration and are a sign the soil ecosystem is active.
If you want, you can describe the mud structure a bit more (color, exact shape, or if there are many of them), and I can confirm 100% whether it’s crayfish or something else—because a couple other creatures can make similar structures. 🧐
