Brown Recluse Spider Fangs
This rather intimidating looking photo, taken by Kansas University researchers, is actually a picture of a Brown Recluse spider attempting to bite a regular no. 10 staple. Notice that the fangs aren't even as long as the staple is thick. The fangs are smaller than a sewing needle and the edge of a dime. They are too short to bite through regular clothes so they typically need bare skin in order to successfully bite you.
Interestingly, their experiments demonstrated that the Brown Recluse wouldn't try to bite if something touched its legs, its underside or anywhere on its body unless there was pressure. Pressure meaning they feel like they are getting squashed by something such as getting caught inside clothes, shoes, or rolling over a Brown Recluse spider who happens to be crawling on your bed at night. Almost all Brown Recluse bites are from incidental contact like this rather than aggression.
Thomas J. Martincic
Brown Recluse Response Team