I seem to recall that there is one species of spider that lives in a hole in the ground

really? funnelhole spiders are unique to living in the ground? i didn't know that.

but spiders live in holes in wood, (and under bits of bark) and in other creavases. they live in small dark places...
and i guess too, they are scarier to come across than a ferret.. (don't know of any poisonous species of ferret!)