Imagine that one day, like any other, you step outside and start seeing frogs falling on cars, on the asphalt, and of course, on your head. Some might start shouting that all is lost and there's no escape, but in truth, rains of toads, fish, and even spiders (?!?) are not impossible. Although a solid confirmation has not been obtained, the main hypothesis suggests that these animals (especially those of aquatic origin) end up in the air because of waterspouts.
Reports of animals falling from the sky go back to antiquity. Pliny the Elder documented a "hail of frogs", and we must not forget that one of the plagues of Egypt also consisted of frogs (although technically they did not appear as rain). In the last 20 years, dozens of cases have been recorded around the world. Wales, England, India, Australia, Philippines, Uruguay, Argentina, Mexico, Brazil, Japan, Hungary, United States... it is clear that geography is not a limitation for these events, and the same applies to the type of animal. Sometimes they are frogs or fish, and sometimes... spiders. But before grabbing a flamethrower, the right thing is to try to find a scientific explanation.
In the specific case of spiders, their fall from the skies is a product of the so-called "spider flight" or "ballooning". The process consists of hanging from a high point and releasing several strands of silk into the air, which behave like "sails" once the wind blows. Due to the reduced mass of the spider-thread set, currents can move the insects for hundreds of kilometers. Now, why do they do this? Ballooning is an escape resource in the face of major catastrophes such as floods or forest fires. For example, the floods that Pakistan suffered in 2010 caused a massive displacement of spiders via ballooning. The strangest thing is that the process has a positive profile (beyond its potential to ruin crops), since spiders control the population of certain insects (for example, mosquitoes) and also serve as food for other animals. The good news? Ballooning is only compatible with very small species, or newborn spiders. No flying tarantulas. (...)
If we move on to frogs and fish, finding a conclusive reason becomes more complicated, starting with the simple fact that no one has been a direct witness of the process, but the strongest hypotheses point to the intervention of waterspouts and tornadoes in general. The vast majority of waterspouts are not that powerful (they never go beyond F0), however, waterspouts with tornado origin tell another story. Remember that some conventional tornadoes have moved pieces of metal up to 80 kilometers from their place of origin, and several of the reported events coincide with the development of large storms and winds. What cannot be explained yet is why it affects "only frogs" or "only fish", and no mixture of aquatic life is observed. Perhaps the size and weight of the animals play a more critical role than is believed, but additional information is needed.
