Thoreau writes in his journal:
See that long meandering track where a deer mouse hopped over the soft snow last night, scarcely making any impression. What if you could witness with owls’ eyes the revelry of the wood mice some night, frisking about the wood like so many little kangaroos? Here is a palpable evidence that the woods are nightly thronged with little creatures which most have never seen,-such populousness as commonly only the imagination dreams of . . .