Wild Squash

Here's a real oddity we found while on our walk today. We were traveling over a small creek and I looked down on the bank to see what looked like gourds on a vine growing there. I looked it up and it is Cucurbita moschata, an edible squash related to the butternut squash! What in the world was it doing growing there? I could only find the one clump of vines in the area so it is a real puzzle.