It has always been thought that because spiders don’t have ears or eardrums, they can “hear” sounds only up to a couple inches away. A recent discovery with jumping spiders showed that these spiders actually have a much more acute sense of hearing than ever believed.
Spiders have very sensitive hairs on their legs that can feel vibrations. These hairs are so sensitive that they can feel the vibrations that sounds make. Using a new technique, researchers were able to get in the spider’s brain and see when neurons fire. The spiders were able to hear sounds up to 16 feet away.
So, could spiders be overhearing our conversations? Much is still unknown about what spiders can and can’t hear. The jumping spiders were most sensitive to sound frequencies that would enable them to hear the beating wings of certain kinds of wasps that parasitize them—the spiders would stop and remain motionless when they heard those sounds.
Spiders may never have developed an ability to hear voices, or other sounds that do not immediately threaten them. These tests were done with jumping spiders. Other kinds of spiders are now being tested, to determine what they can and can’t hear.