我将尝试一些答案,但必须承认这有点投机。我认为,像许多不寻常的/罕见的现象,有不少观测偏差和涉及的心理学。# # # #机制我记得阅读有关气象刊物,这至少在两个受欢迎的一本关于极端和奇怪的天气,一篇文章在“天气”(我认为),英国气象学会》杂志上。不幸的是我没有确切的来源和工作记忆。在我的印象中,这是公认的龙卷风和类似的现象,这是已知的解除和携带水和碎片,有时原则上捡小动物,然后会在一定距离时,龙卷风溶解。龙卷风不只是突然停止,但也会变得更弱,所以碎片和可能的动物都不会落在同一时间就像一个巨大的群体,但是一些在不同的位置。历史# # # #也有——你还发现许多历史报告。收集的许多人Forteans(回到查尔斯堡,他毕生致力于收集不同寻常的观察),但是质量不同,通常从粗心的观察者,而不是科学家。如此随意的报道不寻常的观察,经常从报纸和第二/第三手,你必须考虑到这个故事改变的告诉,不得报道完全按照它的发生而笑。所以,2或3鱼可能成为整个群,和它可能是人们看到他们下降而事实上他们只是发现了一些死鱼在干燥的地面,不能立即解决他们是从哪里来的。 That there are various effects that change peoples' perception of unsual phenomena, and how they are subsequently reported, is better established for other, more frequent sightings like ghosts or UFOs, and of course eyewitness reports of crimes, where there is huge body of psychological research. Basically, what people report (and sincerely believe to be a true observation) is often not exactly what happened, and media reports are even less reliable. So it's not so easy to establish how frequently this really happens. While (unlike ghosts) it's not scientifically impossible and a credible mechanism (tornadoes) exists, it's rare enough that we don't have really good, comprehensive observations. Now for your questions: ## Why one type of animal? ## It seems generally fish and frogs. I think there are two reasons, one meteorological and one psychological. A tornado has to pick up the animals in the first place. These would be have to be small animals. Now, the density of fish and frogs in a pond is often very high, so if a tornado moves over a pond or lake sucks up water, there is a chance that it would lift hundreds or thousands of fish or frogs, so it is much more likely, when thy fall, that they are seen or found. Small land animals, like mice, tend not to live in such dense populations, and also run away or bury themselves in the ground. So while some will certainly be sucked up in a tornadoe, it's much less likely and probably not many. The second factor is psychological. Many observations are not actually of the animal falling down, but of animals lying on the ground that shouldn't be there. So, if there's a fish or frog lying ion dry ground after a weather event, people would notice and report it. If they find a dead mouse, they wouldn't notice. Also, mice are good at falling from height, so they may survive and just run away and never be seen, whereas a fish on land, will just die and start to stink after a while (and therefore be noticed...). ## Why no videos? ## There's an observational problem here. Ideally a scientist would like to observe first the animals being sucked up, and then falling. Now, tornadoes are not that easy to observe at close range, so observing animals being sucked in is technically very difficult. Observing when the animals fall is in principle possible, but probably extremely unlikely. First of all, the event itself is unlikely (see above). Then, when it happens, more frequently it's probably just one fish suddenly coming down unexpectedly, not a longer "rain" of fish. So unless you were already filming for some other reason and catch it by chance, you wouldn't have time to get out the camera and actually film it falling.