Why is there a crawfish living in my basement?

[Sicks Ate]

Take a guess, yours is a good as mine!

Background: I have an old house with a ratty old basement. It used to be just dirt floor, but at some point a previous owner skimmed an inch or two of concrete on the floor.

The basement was prone to flooding during heavy rain, partially due to a non-functional floor drain. A couple years ago I got fed up with the water, so I bashed a hole in the floor and installed a sump pit and pump.

I intended to get some sackrete and patch around where I put the basin, but never got around to it. So around the outside of it is a few inches of gravel, a few inches of dirt, then the concrete 'floor' again.

Not too long after that, I noticed that something had been burrowing where the dirt met the concrete, near the edge of the basin. A hole maybe an inch or inch and a half diameter, surrounded by pebbly piles of mud. "That," thought I, "looks like a crawfish hole." But that's silly...it's my basement. WTH would one of those be in there?

Well I caught a glimpse of it one time, and sure as hell that's what it was!

Now, the geography of my house. I live on top of a hill. The nearest body of water is a horse pond a quarter mile away, across some railroad tracks and a bridge. There is nothing like an intermittent stream anywhere near.

How/why is there a crawfish living in my basement??