For many, spiders are a source of dread that sends chills down their spine. If seeing one spider can make one scared, imagine what seeing millions of them would be like! Over a year ago, millions of baby spiders did migrate to a park in Australia leaving the place covered in fine silk threads, a phenomenon known as “ballooning.” It has often been mistaken by UFO enthusiasts for “angel hair,” a sticky fibrous substance reported in connection with UFO sightings or manifestations of the Virgin Mary. Ballooning is also a common method for spiders to reach areas that are otherwise difficult.

In 2016, when Leslie Anne Schmidt and her partner went to a park in Australia to catch a Pokemon, they found it covered in spiderwebs. The spiders fled flooded areas following a recent heavy downpour to escape to a higher ground. 

The park is located in Yinnar, a rural township in central Gippsland, Victoria, Australia. Heavy rains in that region have forced the spiders, especially juvenile wolf spiders and money spiders, to parachute themselves to safety using a technique known as “ballooning.” According to Leslie Anne Schmidt, she and her partner were trying to catch Meowth, a creature from the Pokemon game, when they went to the park and found it blanketed with a layer of spider silk.

Spiderlings often climb to the highest point they could reach and release fine silk threads that work like a parachute and carry them away in the air currents. They do this to flee from floodwater or to disperse to a new location after hatching. 

The ballooning behavior, also known as “kiting,” is mostly limited to juvenile spiders or species of spiders that are small in size. It is generally thought that spiders weighing over one milligram are unlikely to achieve liftoff, but adult females of some species weighing over 100 milligrams were observed using air movement in thermal columns for liftoffs on hot days without winds. The spiderlings use especially fine silk that scientists metaphorically call “gossamer” which they release from their spinnerets into the air forming a triangular-shaped parachute. Any updrafts of wind, the slightest of breezes, or even Earth’s static electric field on windless days provide these arachnids the liftoff they need.

Spiders use ballooning as a means of migration which enables them to reach isolated locations that are impossible to reach by land. They are known to travel as far as 1,600 kilometers in the air and for as many as 25 days.

Ballooning spiders have been found to have traveled anywhere from a few meters to hundreds of kilometers. Many sailors have reported spiders being caught in the ship’s sails when they are over 1,600 kilometers (990 miles) from the land. They have even been detected in atmospheric samples collected from balloons at altitudes as high as five kilometers (16,000 feet) both above Earth’s surface and mid-ocean. Ballooning is considered the most common ways in which spiders invade isolated islands and mountaintops.

The spiderlings don’t always survive their trip during ballooning and mortality is high. However, they have been known to survive without food for as long as 25 days while traveling. They can land on both land and water. They use their water-repellent legs to stay alive if they land on water, fresh or salty. Some mites and caterpillars also use silk to disperse in the air.

This wasn’t the first time the spiders have gone on a mass ballooning trip. In March 2012, millions of them migrated to Australia’s Southern Tablelands covering the countryside so completely that it looked like it snowed.

In March 2012, eastern Australia faced floods considered the worst in past 160 years after a decade-long drought and bushfires. At least 13,000 people fled their homes. Following the floods, several millions of spiders migrated to the countryside of Wagga Wagga, New South Wales, Australia. Such massive ballooning events are not unique to Australia. It has been spotted elsewhere in the Northern Hemisphere, especially the United States and Britain, where according to Bennett it is a “relatively rare and random” event. Another recorded instance was in 2010 when the trees in the village of Sindh, Pakistan, were cocooned in spider webs following unprecedented monsoons in July that flooded the country’s rivers.

[sources: DailyMail, Wikipedia, NationalGeographic]