Arachnophobics, beware: Spiders can hear you from across the room.
While it’s already well known that spiders can “hear” sounds through their leg hairs in response to vibrations, scientists had previously thought that they could only do so within several inches of those vibrations.
It has now been determined, however, that spiders can detect vibrations through both air and solid objects up to 16 feet away.
Gil Menda of Cornell University recently conducted the study on jumping spiders where she and her colleagues placed microelectrodes into the spiders’ brains to see how they would respond to sounds at certain distances. These microelectrodes detected neurons responding to sounds like people moving chairs, talking, or clapping.
Menda told New Scientist, “We were very surprised. Our studies extended the range of auditory sensitivity to more than 3 metres – over 350 body lengths – for our spiders.” She continued, “Spiders can hear humans talking and walking, which is within the audible range.”
The team determined that the spiders responded to low-frequency sounds of 80 to 400 hertz; adult humans generally speak in frequencies between 85 and 255 hertz. These frequencies also resemble the low hums or buzzes of wingbeat frequency of predatory insects. By hearing this frequency range, spiders can protect themselves by avoiding predators.
While the tests were conducted on jumping spiders, scientists believe that it applies to other spiders as well. Menda’s colleague Paul Shamble added, “All spiders have these hairs, so it seems likely this is something that lots of spiders can do, as opposed to something exclusive to jumping spiders.”
