Spider Rain Science Facts™
- First of all: What is Spider Rain?
Spider rain refers to events of mass ballooning. many spiders have the ability to move through air by using spider silk as a sort of parachute. that’s right: spiders can FLY.
when spiders do this en masse, you get millions of spiders travelling through the air on gossamer strands of silk (the phenomenon is also nicknamed “angel hair”). if you aren’t afraid of spiders, apparently this can be quite beautiful to watch. in fact, i would argue it should be called spider snow, not rain, bc many viewers report the combination of white silk threads and the gentle floating motion make it resemble snowfall. except for, you know. all the spiders. (video here)
Spider rain is not uncommon, though the size and location varies. Theoretically, it can happen anywhere that colonies of social spiders live. These colonies are scattered around the world, but they only consist of 23 species, compared to over 45,000 non-social spider species. Spider rain usually occurs in unpopulated or rural areas, but occasionally the wind can turn (literally) and spiders accidentally end up is urban areas, as happened in Australia, where spider rain is most common (*pretends to be shocked*).
In fact, not all spider rain happens on purpose! Strong winds blowing through a colony can pull webs off their anchors, leaving spider and home airborne, as happened in Brazil where: “While the humans gawked below, the flustered spiders were simply trying to pull themselves together after an unexpected journey.” Spider rain is highly dependent on local weather, which provides spiders with both the ability and sometimes the need to migrate (as happened in Pakistan after widespread flooding).
And before the Americans breathe a sign of relief–it hasn’t happened in Texas yet, but there’s a colony just east of Dallas to keep an eye on :)
- How do we stop it happening?
We don’t. It’s….not really a problem? The spiders are like, really tiny, so even the venomous ones aren’t able to bite humans–our skin is just too thick for their itty bitty fangs. It’s still occasionally a pest issue, with the main issue being that their webs can be thick enough to cut off sunlight from crops.
But spider rain is mostly harmless (unless you are a spectacularly unlucky farmer), and it doesn’t happen often enough to pose a real problem. The real risk is to the spiders–most of them aren’t expected to survive the trip. Fortunately, only a small percentage of them need to in order for the colony to survive and set up shop somewhere new.
Overall, spider rain is a good thing! The spiders keep the skies free of disease-carrying insects, and in turn provide food to birds and small animals. It’s beneficial that a staple of the food chain can disperse so widely and quickly. In fact, ballooning is one of the reasons spiders are often the first animal to reappear on land that’s been destroyed. Their appearance after a fire or flood is a sign the ecosystem is recovering. which is, sort of beautiful actually.
and here’s a photo of a spider colony