The spiders that make webs – orb weavers and cobweb spiders, for example – use their silk to ensnare prey. Should a fly or moth unwittingly wander into a web, it becomes instantly entangled. The spider, on the other hand, can rush across the web to enjoy its freshly captured meal without fear of finding herself trapped. Did you ever wonder why spiders don't get stuck in their webs?
If you've ever had the pleasure of walking into a spider web and having silk plastered on your face, you know it's kind of a sticky, clingy substance. A moth that flies full speed into such a trap doesn't stand much of a chance of freeing itself. But in both cases, the unsuspecting victims came in full contact with the spider silk. The spider, on the other hand, doesn't tumble willy-nilly into its web. Watch a spider traverse its web, and you will notice it takes careful steps, tiptoeing delicately from thread to thread. Only the tips of each leg make contact with the silk. This minimizes the chances of the spider becoming ensnared in its own trap.
Spiders are also careful groomers. If you observe a spider at length, you may see her pull each leg through her mouth, gently scraping off any silk bits and other debris that inadvertently stuck to her claws or bristles. Meticulous grooming probably ensures that her legs and body are less prone to sticking, should she suffer a misstep in the web.
Even if a disheveled, clumsy spider should trip and fall into its own web, it's not likely to get stuck. Contrary to popular belief, not all spider silk is sticky. In most orb weaver webs, for example, only the spiral threads have adhesive qualities. The spokes of the web, as well as the center of the web where the spider rests, are constructed without "glue." She can use these threads as pathways to walk around the web without sticking. In some webs, the silk is dotted with glue globules, not completely coated in adhesive. The spider can avoid the sticky spots. Some spider webs, such as those made by funnel web spiders or sheet weavers, are constructed only of dry silk.
A common misconception about spiders is that some kind of natural lubricant or oil on their legs prevents silk from adhering to them. This is entirely false. Spiders do not have oil-producing glands, nor are their legs coated in any such substance.