Gliding Spiders? Amazonian Arachnids Fall With Style [Videos]
"That's not flying! That's falling... with style." The memorable words of Tom Hanks as Toy Story's Sheriff Woody Pride would certainly apply here. Like Buzz Lightyear himself, the tree-hopping spiders of South American canopies have been revealed to fall with more grace than ever expected, stylishly gliding from one trunk to another to avoid predators.
That's at least according to a study recently published in the Journal of the Royal Society Interface, which details how researchers mercilessly dropped 59 large arboreal spiders from the tree-tops of forests in Panama and Peru.
What they found amazed them. Traditionally spiders will rely on their tough exoskeletons and relatively light weight to survive a fall. However for spiders in the Amazon rainforest, this won't be enough. Being stranded on the forest floor, even for a short amount of time, could spell certain death for these arachnids, with many local predators constantly on the lookout for an eight legged treat.
To avoid this fate, the spiders appear to have developed a technique that directs their decent, with the majority (93%) of the dropped spiders aiming for and eventually landing on a nearby trunk.
To find out how this works, researches then took the spiders, of the genus Selenops (Selenopidae), to a lab-side wind tunnel. Tests and observations revealed that these stylish fallers opt to fall head first, using their front legs almost like rudders to steer them to safety.
What's amazing is that this is actually the first time controlled gliding has ever been demonstrated in arachnids. Researchers have long known that many smaller web-weaving spiders will use silk lines to catch and ride the wind in an action called "ballooning" - a behavior that has even led to some spiders learning how to sail. However, free-falling with such style? That's a new trick that even Woody would admit looks pretty darn cool.
(Videos: Tanociak et al. the Royal Society Interface (2015))
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