The English language is full of proverbs, idioms, and lore about nature predicting the weather, all with varying accuracy. A bountiful berry season means a cold winter ahead. When dogs eat grass, cats sneeze, and sheep turn in the wind, rain is coming. The wider the black bands are on a woolly worm, the harsher the upcoming winter. And who can forget Punxsutawney Phil, who allegedly uses his shadow (or lack thereof) to determine how soon spring will come?
Of course, no animal actually uses his or her shadow to figure out the next two months of weather reports; they use their ears, food supply, sense of touch, and smell. Even humans can sense a summer storm approaching, but flora and fauna have increased abilities for predicting the weather because of the special sensitivities they possess. A snake might sense an earthquake several seconds before a person, for example, because of how that snake’s body absorbs movement (not to mention its trajectory to the ground). Similarly, because of an enhanced sense of smell, many animals can smell rain coming from much further away than people.
Some old-school claims do have merit (such as the aforementioned berry theory), while others are tougher to prove (like the woolly worm theory). To separate fact from fiction, Stacker looked into 10 scientifically proven ways nature and animals forecast the weather. We’ve used primary sources and scientific studies to back up the following claims, proving that animals do indeed have ways of foretelling storms, sky color is a powerful indicator of incoming weather, and flowers and trees get ready for rain. Keep reading to find out 10 fascinating ways nature and animals predict the weather.
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Infrasound is a low-frequency noise that falls below 20 cycles per second (or Hz), the average base threshold for human hearing. Meteors, explosive volcanic eruptions, heavy storms, and supersonic aircraft are all sources of infrasound, and all are audible to animals, from alligators and whales to pigeons. Migratory birds rely on infrasound to avoid storms during transit, according to findings in a 2014 study from UC Berkeley. With this in mind, Technology International in 2013 developed infrasound subwoofers for planes to drive infrasound into the air to scare birds away and prevent crashes.
In another study led by ecologist Henry Streby at UC Berkeley, researchers in 2014 found golden-winged warblers nesting in Tennessee evacuated their breeding areas and headed for the Gulf of Mexico a day or two before supercell storms arrived in the area. When the birds left the storm was between 250 and 560 miles away; as soon as the storm dissipated, the birds returned. The study inferred that the birds’ heightened ability to hear infrasound was the likeliest explanation for the phenomenon.
Until 2009, the oft-repeated claim that toads can anticipate earthquakes was without scientific study to back it up. That’s when researchers in the U.K. followed the behavior of Bufo bufo toads (prevalent throughout Europe) over 29 days from before until after an earthquake in April 2009 in L’Aquila, Italy. The monitored toads, despite being almost 46 miles from the city, showed marked behavioral changes about five days before the earthquake occurred.
The findings showed that male toads become far less active at breeding sites in the time leading up to an earthquake, with a 96% reduction in the number of males in the breeding colony five days before. Exactly how the toads know is as-yet undetermined; however, scientists reason the animals are likely sensitive to changes in the ionosphere, the electromagnetic layer of the Earth’s atmosphere.
Similar to many flowers, daisies close their petals at night and open them with the sun each day in a behavior called nyctinasty. But daisies—along with poppies, tulips, and several other flowers—take it a step further, shutting their petals up during the day when rain is on its way. This action protects the flower’s pollen and is caused by the plant’s upper and lower parts growing at different rates according to the weather.
At night or before a storm, temperatures drop, causing the underside of the flower to grow faster and forcing the petals closed. In warm weather when the sun is shining, the upper part of the flower grows more quickly and is held open. Next time you see a flower with its petals shut up tight in the middle of the day, it’s a safe bet there is rain coming.
The old sailor saying “Red sky at night, sailor’s delight; red sky in morning, sailor take warning” uses sky color to predict stormy weather on the high seas. And while it sounds more like mythology than fact, there is some science to back it up.
In the U.S., most weather systems move west to east. So in the early morning, a rising sun in the east will cast light on incoming clouds, tinting the sky red. Conversely, a setting sun in the west casts light onto any departing clouds, turning the sky red and indicating a clear day following.
All animals react to barometric pressure, including people (just ask anyone who gets achy joints or migraines ahead of intense weather). But frogs are all too happy to share their weather premonitions with the world, calling louder when storms approach. That’s because storms create massive drops in air and water pressure at shallow depths, which frogs are highly sensitive to.
Frogs’ reactions to increased humidity and pressure drops are twofold: Frogs can stay out of water longer in higher humidity, creating an increased croaking period. Frogs also lay eggs in nearby bodies of water—so more rain means more temporary ponds, puddles, and water in which to do so. More water means more potential for more offspring; so an actively croaking frog is also actively recruiting a mate to lay fertilized eggs.
Male crickets can chirp thanks to stridulation, the process of rubbing certain body parts together to produce sounds. Crickets stridulate by running one wing along the wrinkles on the bottom of the other (which the writers at Scientific American compare to running your finger across a comb).
They’re not alone—tarantulas and rock spiders also stridulate, as do several other critters. But when crickets make their sounds, you can actually tell the temperature. If you can isolate the chirp of one cricket, count the chirp in 14-second intervals and then find the average. Add 40 to that number, and you’ve got a rough estimate of outdoor temperature in Fahrenheit. The theory’s been proven so many times over, it’s even featured in the well-respected Farmer’s Almanac.
A halo forms around the sun and moon anytime light bends while traveling through high-altitude ice crystals, according to the National Snow and Ice Data Center. The sun or moon rings act as indicators of precipitation, letting anyone looking up know rain or snow is on its way.
Researchers who in 2016 affixed radio-frequency identification tags to 300 worker bees from three separate hives found that the bees spent more time working outside their respective hives 24 hours before it rained than on a day preceding clear skies. New Scientist reported the researchers concluded the bees were responding to cues from fluctuating temperature, drops in barometric pressure, and humidity.
As pine cones mature and dry out, the rigid scales of the female cones gape enough to release seeds. But seed-bearing cones also open and close with the weather. A 1997 study published in Nature found pine cone scales respond to relative humidity, as well, opening when the weather is dry and closing when humidity levels rise.
It’s easy to test: The next time you find a living pine cone, put it in a bowl of water and see what its scales do. Next time you see pinecones hanging in a tree closed up, you can be all but certain there’s rain on the horizon.
Like other plants and animals in this slide show, deciduous trees also respond to dramatic fluctuations in humidity—or, as the adage goes, "When leaves show their undersides, be very sure rain betides." When the humidity spikes before a heavy downpour, leaves attached to the soft stems of trees such as maples soften. The weakened stems make it easy for the leaves to flip upside down in the wind.