My turtle dug a hole in the yard why is it doing this?

I used to own a turtle, and when it dug a hole it had actually lain eggs! I was surprised at this because I didn't know it had mated. You should check to see if this is the reason. If not, then another reason your turtle may be digging a hole is because it just needs a 'den', or that it may need to dispose of body wastes. (fecal matter, ect.)