Science Photo Answer #841
Nancy found this spider today, and I thought at first glance that it might be a Hobo spider. What is special about Hobo spiders?
Hobo spiders probably have some of the worst PR in the spider world. Because of its scientific name (Tegenaria agrestis), it is often called the Aggressive House Spider. Actually, agrestis means rural, not aggressive, but it still gets an undeserved reputation for being aggressive. In 1987, a researcher reported that Hobo spider venom had caused lesions and tissue damage to rabbits, producing results much like the bite of a brown recluse spider. That one study had a huge impact. A quick internet search will show thousands of sites detailing the dangers of Hobo spiders. Repeated attempts to replicate that study have failed to support the idea that these spiders are dangerous to people, including a study published in the Journal of Medical Entomology which tested the spider's venom and found that it is incapable of causing the type of lesions described in the first study. You can find the study here: http://www.bioone.org/doi/abs/10.1603/ME09224
This is an excellent example of why it is so important to fact check scientific information.