I remember an old house I crawled under. The access was typical of old homes-so small you have to wedge your belt buckle past the frame. It took me a couple of minutes of contorting to get in. I shone the light around and saw a black pile in the corner about 10 feet away. Black fur, White stripe just visible. I was back outside in less than 15 seconds.
The lady who owned the house said to come back in a couple of days; she'll just throw moth balls under the house and any critters will leave.