Spider webs are already impressive architectural feats, but new research reveals that these structures have another amazing property that's invisible to the human eye. Like a violin string, each silk thread, when plucked or moved, is capable of producing a unique acoustic signature. Those varying vibrations, researchers told National Georgraphic, alert the spider to the activities of its silken home, from a trapped insect to damage that needs to be repaired.
These acoustic properties likely evolved because of spiders' poor eyesight, NatGeo writes. They can't see an insect trapped in their web, but they can feel and hear its vibrations as it struggles to escape. Spiders also pluck at their web strings themselves, sending out probing acoustic feelers to different corners of their web, and registering that information through not one but eight legs, NatGeo describes. The spiders, the researchers report, can register movements that occur on a scale as small as 1/1000th the width of a human hair.
The silk, it seems, is specially designed for this purpose. In trials, researchers found that it has a much broader acoustic range than other fibers they tested (both ones found in nature and ones produced in the lab). As NatGeo points out, materials scientists are also excited about this finding since it might lead to improved supersensory devices.