Why Doesn’t a Spider Get Caught in Its Own Web?
Spiders build their webs to trap flies and other insects for food. An insect is unable to escape once it has become caught in the spider’s web. The more the insect struggles, the more it becomes entangled in the sticky threads. A spider’s silk is strong enough that most insects cannot break through it.
A web-spinning spider does not become caught in its own web. When walking across the web, it grasps the silk threads with a special hooked claw on each foot. The spider also secretes a special chemical onto its legs and feet that prevents the sticky silk from sticking to its body.
Unlike unsuspecting prey, spiders don’t come into contact with their webs all at once. Instead, they move nimbly along the strands of their webs with only the hairs on the tips of their legs making contact with the sticky threads. This minimizes the chances that they’ll get caught in their own trap!
To avoid sticky situations, spiders also groom themselves very carefully. Spiders routinely clean their legs of all pieces of silk and other debris that might cause them to get stuck on their webs.
Not all webs are sticky throughout, either. Many spiders only make threads with adhesive “glue” in certain parts of their webs. Other areas, especially where the spider might rest, are built without “glue” to make it easier for the spider to move around the web.
Some people mistakenly believe that spiders have oily legs that prevent them from sticking to their webs. This is not true, because spiders don’t have oil glands. Recently, though, some scientists have discovered that the hair on a spider’s legs may be covered with a special chemical that prevents the “glue” on the web from sticking.