Until recently, spiders were thought devoid of hearing. The arachnids were thought to act primarily on sight and touch, their hearing sense being limited to only a few inches away from them. But even if they are not equipped with ears, like mammals, a new study shows that, in fact, spiders can hear.
While this may apply to more than one species, the spider that was first proved to possess this ability is Phiddipus audax, also known as the jumping spider. The experiment that showed the arachnid’s hearing ability started more or less as an accident.
Using metal microelectrodes inserted into the spider’s brain, researchers Paul Shamble and Gil Menda were actually trying to study the spider’s sight. When Menda accidentally made some noise with a chair, the researchers at the Cornell University quickly realized that the spider’s brain showed some neuronal activity.
Shamble decided to approach his study from a new direction. Using the same neuronal monitoring technique, they quickly came to the conclusion that jumping spiders can hear sounds coming from a maximum of 10 feet away.
“The sensory world of the tiny jumping spider was thought to be dominated by sight and tactile touch,” said Paul Shamble.
The team of researchers also added that the noise which spiders can hear best is the one made by the flapping wings of wasps, which are the spider’s natural enemy.
The research team has also recorded videos at high-speed to monitor how spiders react to sound. The jumping spider has also been shown to freeze if being startled by certain sounds, at a frequency of 90 Hz.
As previously noted, spiders lack ears, so it was also important to know exactly how the arachnids can detect sounds. Shamble noted that, when touching the spider’s hair on its legs, they recorded the same neuronal response in the arachnid’s brain. In other words, spiders can hear using their hairy legs.
So far, the jumping spider’s amazing sensory capabilities have amazed all the scientists involved in the study. They have proceeded with conducting the experiment on other species of spiders, as well. Among those found to possess similar hearing capabilities were net-casting spiders, wolf spiders and fishing spiders.
Image source: Wikipedia