Spiders rain from the sky.
Spiders rain from the sky.

Horror as spiders ‘rain’ from sky

IN what may be every arachnophobes worst nightmare, footage has been posted online showing the sky in Brazil filled with hundreds of spiders as they appear to rain down from above.

The video shows spiders clustered in the air at Espírito Santo do Dourado, about 250km northeast of São Paulo, with locals describing the seeing the sky "raining with spiders".

Though the arachnids may look like they are falling, they are actually moving about on top of a huge canopy-like web, with experts saying it is typical for the region when it is hot and humid to form a temporary shared web.

João Pedro Martinelli Fonseca, who filmed one of the videos at his grandparent's farm, told local newspapers that he was "stunned and scared".

Though we may see a huge canopy of spiders form in the sky here in Australia, it is likely that we have the odd spider floating around in our midst.

It turns out spiders can fly for hundreds of kilometres using a special trick called ballooning.

Spiders detect electric fields at levels found under natural atmospheric conditions, which triggers the act of ballooning. Experts have even figured out electric fields are what actually elicit the ballooning behaviour.

More simply put, ballooning involves ascending to a high point on foliage and letting out fine silk lines that catch the breeze and eventually gain enough lift to waft the spider up and away.

Researchers who have studied the unusual behaviour say when people think of airborne organisms, spiders don't usually come to mind.

"However, these wingless arthropods have been found 4km up in the sky, dispersing hundreds of kilometres," they point out.

While the long distance trips can happen, spiders usually travel anywhere between a few metres and a few kilometres.