Mental Floss

This Skydiving Spider Can Target You From Above

Mental Floss UK
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by James Hunt

We recently saw that certain species of spider can walk on water, but now it seems that there's yet another way arachnophobes can be surprised by the object of their nightmares: from above. Because biologists have just discovered that a species of spider common across the globe can apparently skydive.

As observed in Panama and Peru, the gliding spiders are nocturnal hunters about two inches long and can actually steer in mid-air while falling, allowing them to return to the tree from which they originally leapt. This raises many questions, not the least of which is whether the spiders can actually see the tree thanks to acute vision, or if they're navigating using some other sense.

The spider is from the genus Selenops, which is named after Selene, the Greek goddess of the moon. The suffix -ops (as in optics) refers to its moon-like eyes. The genus exists all over the world, with 115 known species that look nearly identical, but it's not yet clear whether they all have the ability to glide or that trait is specific just the South American varieties. If the trait is common, it could mean that gliding spiders exist on almost every continent.

Researchers studied 59 individual spiders, each of which showed some gliding ability. They attribute this trait to the species' "wafer thin," flexible frames, and their ability to spread their legs in order to strategically "steer" while falling. (They can even right themselves if they become inverted mid-descent.)

Robert Dudley, a professor of integrative biology at the University of California, Berkeley, points out that studying this type of behavior may allow humans to build robots that can perform similar feats in the future. And frankly, building robots that can defend us against skydiving spiders sounds like a good idea to us.