In its natural habitat the species prefers rotten tree bark as the favorite place to make the nest, but it is also found in alls sorts of house corners. The only habitat specificities that matter are retreat and low moisture levels. Brown recluse spiders are not dangerous or aggressive; the only cases of bites occur when these creatures somehow get tangled in clothes, towels or even bed sheets. The curious fact is that lots of brown recluse spider bites have been reported in parts of America where this species does not live. There are other spider varieties to blame for the matter, but none of them causes necrosis, not even the Hobo spider, that is often held responsible. The brown recluse spider bites are the only ones to cause necrosis but in very rare situations and when the immunity of the victim is very low. Even in North America there are three different types of the black widow spider and their classification is made according to the geographical area where they live: there is the northern black widow, the southern black widow and the western black widow; thus the species is widely spread from the south of Canada to Mexico. The preference for shade is the actual explanation of the impression lots of people got that the spiders may be attacking them. The human body represents a corner of shade, which will surely attract the spiders; this is the only explanation for the fact that these creatures get closer to humans in a variety of circumstances. The specificity of their vision organs is the one that ensures the survival of the species since the wolf spider depends on the eyesight to hunt. Furthermore, as they spend most of their time at ground level, these creature also have a very well-developed sense of touch. The wolf spider is not an aggressive species, though it may bite if provoked or threatened. The female funnel web spider lives very isolated, it remains in the burrow for almost its entire life; males are the ones that go out to hunt and find mates particularly in summer and autumn months. The number of reported bites is the highest during the mating season when the funnel web spider males enter in houses and garages through small gaps in the doors and window sills.