Researchers have recently discovered that jumping spiders can hear from afar. They can’t actually hear, because they don’t have ears, but they can sense a presence. Specialists believe that their mechanism only functioned when the insects are close to a scene, but recent research shows that their sense is much more accurate than that.
Previous studies focused mostly on the visual sense of jumping spiders, whose eight eyes provide them with an accurate view of the surroundings. However, the new study accounts for the spiders’ ability of perceiving sounds from afar. Researchers previously believed that the insects could hear sounds within a few inches around them. The new findings show that the area extends now to several feet.
The ability of hearing sounds from afar is specific for mammals displaying an eardrum, as specialists explain. This is not the case of jumping spiders, although they do possess the remarkable feature.
The interesting fact about the discovery is that researchers didn’t intend to study this aspect. They were performing tests to check the brain activity of jumping spiders and the connection to their visual ability. However, they observed brain activity for distant noises in the room.
What actually happened was that one of the researchers dragged a chair in one of the corners of the lab. The spiders detected the noise, and their brain reacted as such. The researchers were extremely surprised by the discovery.
The next steps of their improvised experiment were to obtain the same reaction from the spiders again. So the specialists started producing noises close to the insects, then take some distance, in a gradual process. This is how they discovered that jumping spiders could perceive sounds produced as far as ten feet away from them.
During their lab experiments, the scientists observed that the spiders are most alert by sounds similar to those of their natural enemies, namely wasps. They detect the sounds of beating wings by perceiving the air vibrations. Their brain activity increases on such occasions, translating as signs of fear and defense attitude.
The spiders’ visual and hearing senses combine to keep the arthropods safe from predators. The senses also help them hunt and catch their prey. They are active mostly during the day, and although they are characterized as slow creatures, they can also jump and make rapid movements.
The new study accounting for the ability of jumping spiders to hear from afar was published in Current Biology.
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