In São Tomé das Letras, a town in the Brazilian state of Minas Gerais, residents were astonished when hundreds of spiders appeared to float in the sky like black snowflakes. The images recorded that day showed what seemed to be a surreal spider rain, leaving locals unsettled.
According to eyewitness accounts, the spiders descended in large numbers, giving the impression that they were falling from the sky. Videos of the event circulated widely on social media, prompting reactions of disbelief and curiosity. One resident described the occurrence as "spider rain," expressing fear upon witnessing the phenomenon for the first time in a relative's backyard in Tiradentes, a nearby town.
"The videos show hundreds of spiders descending from the sky, in a scene that can be likened to snowfall," reported local media. This rare natural phenomenon puzzled many internet users, who likened the spiders' movements to "dancing like raindrops on the horizon."
Experts clarified that the spiders were not actually falling from the sky but were suspended in a large, almost invisible web. Biologists explained that this is a collective mating ritual, where swarms of spiders gather on a huge web to reproduce.
"This is a spider orgy," said biologist Kayron Passos, according to Het Nieuwsblad. "The females have something called a spermatheca, where they store the sperm of different males to fertilize the eggs. In this way, the female ensures that she will have many different offspring and increases genetic diversity."
@balancogeral 'Chuva' de aranhas surpreende moradores em São Thomé das Letras, Minas Gerais. Essa espécie de aranhas é comumente encontrada no cerrado brasileiro e pode causar o fenômeno aos verões, quando o calor e a umidade são mais expressivos #BalançoGeral ♬ som original - Balanço Geral
Passos further clarified that even after fertilizing their eggs, female spiders continue to collect sperm for future use, enhancing the genetic variation of their progeny. "This behavior increases resistance, making the offspring more resilient to diseases," he explained.
"Generally, spiders do not stay together," said arachnologist Ana Lucia Tourinho, who has a PhD in Biological Sciences and works at the National Institute of Amazonian Research, as reported by SKAI. "But some species exhibit this social behavior of forming colonies."
Tourinho, who has been studying spiders for more than 27 years, elaborated on the benefits of this communal lifestyle. "The colony usually forms every year; most of them in the colony are relatives, usually generations of mothers and daughters together, but after mating, they will disperse," she concluded, according to Het Nieuwsblad.
"The strategy of staying together in a group increases the food supply for the offspring and the juveniles," she added.
Such occurrences, while rare, are not unprecedented in Brazil. In 2013, residents in Santo Antônio da Platina witnessed a similar event when spiders appeared to rain around telephone poles, making international headlines.
Biologists who examined the previous incident concluded that it showed a flock of spiders suspended in a large and almost invisible web, mating in a ritual "orgy" of reproduction.
"I was stunned and scared," said João Pedro Martinelli Fonseca, who filmed the phenomenon and told a local newspaper.
This article was written in collaboration with generative AI company Alchemiq