Hundreds Of Spiders Swarm The Sky In Brazil, Expert Explains Why

A chilling spectacle unfolded in Sao Thome das Letras, Brazil, as hundreds of eight-legged creatures appeared to rain down from the sky. The eerie incident, which resembled a scene from a horror movie, was captured in rare footage and recently shared on social media. The bizarre video sparked widespread curiosity and quickly went viral online, baffling viewers. 

One user shared the video and wrote, "Spiders have taken over the sky in Brazil. This apocalypse happens every year from December to March in hot and humid weather in rural areas. Huge groups of up to 500 spiders weave webs that stretch across the entire sky. There is no danger to humans."

Watch the videos here:

? Spiders have taken over the sky in Brazil. This apocalypse happens every year from December to March in hot and humid weather in rural areas.
Huge groups of up to 500 spiders weave webs that stretch across the entire sky.
No danger to humans. pic.twitter.com/xAjEtUgnnR — Gennady Simanovsky (@GennadySimanovs) February 1, 2025

Sometimes, young spiders use a trick called "ballooning"—they release silk into the air and let the wind carry them. When a lot of them do this at once, it looks like spiders are falling from the sky. #Brazil pic.twitter.com/H4G71ALS2O — Evan Kirstel #B2B #TechFluencer (@EvanKirstel) January 31, 2025

Despite its unsettling appearance, experts have revealed that the spectacle of spiders falling from the sky is a natural occurrence. Biologist Kayron Passos explained that the phenomenon was caused by a massive spider web hosting hundreds of spiders engaged in a synchronised mating ritual. As the spiders concluded their ritual, they released themselves from the web, creating the illusion of spiders raining down from the sky.

Mr Passos said, "It's a spider orgy. The females have something called spermatheca, where they store the semen of different males to fertilise the eggs. This way, the female ensures that she will have several different offspring and increase genetic variability."

Mr Passos further explained that female spiders exhibit a unique reproductive behaviour, where they continue to collect and store sperm from males even after fertilisation has occurred, allowing them to utilize the stored semen for future egg-laying.