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Can Animals Really Anticipate Natural Disasters?

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In 2004, when an 810-mile swath of the Sunda megathrust fault ruptured beneath the Indian Ocean, it triggered a 9.1 magnitude undersea earthquake off the coast of Sumatra, Indonesia, the third largest tremor ever recorded. The abrupt rise of the seabed displaced a staggering volume of water, generating a wave of tsunamis from the quake’s epicenter in every direction.

Some 230,000 people across fourteen coastal countries died, but, in the aftermath, locals and rescuers in certain areas noted a conspicuous absence of animal casualties. In the following weeks and months, stories emerged of some animals acting oddly just before the tsunami hit: Eyewitnesses in Sri Lanka and Thailand told of elephants that trumpeted before seeking higher ground, dogs that refused to go outside, and flamingos that suddenly abandoned low-lying nesting areas. For centuries, anecdotal stories have circulated about animals possessing some primal sixth sense that alerts them to an imminent natural disaster, but does science back it up?

BAD VIBRATIONS

While it’s clear that animals have different or heightened sensory capabilities compared to humans, very few scientists will go on record to support the idea that animals and insects possess a biologically determined sixth sense that allows them to portend coming trouble. In the case of the elephants that reportedly made for higher ground before the tsunami hit, one theory is that they picked up on infrasound waves generated by the tremor. These waves have a fundamental frequency of 20 Hz or lower, and fall outside the limits of normal human hearing (the bottom note on a piano, A0, has a frequency of about 27.5 Hz, and is generally the lowest tone humans can differentiate).

Infrasonic sound waves can be spawned by intensely energetic occurrences like earthquakes, volcanic eruptions, avalanches, lightning, meteors, and iceberg calving. Elephants, rhinos, hippos, whales, felines, dogs, and many birds rely on infrasonic sounds for both communication and navigation. When the Sri Lankan elephants detected the initial low frequency rumblings coming from the Indian Ocean, it wasn’t as if they sensed the coming tsunami, they just instinctively moved away from the source of the sound, which, in this case, happened to be the right decision.

Many animals, insects, and birds are also particularly sensitive to Rayleigh waves, a type of surface wave that travels along solid ground. After the initial rupture, the waves would have traveled through the earth’s crust from the epicenter, causing minute vibrations. The waves are inaudible and travel at ten times the speed of sound, and could therefore have been noticed by those animals sensitive to them well before the slow-moving tsunami crashed ashore. Humans actually have mechanoreceptors in our skin called Pacinian corpuscles which act to detect changes in vibration and pressure, but, as their optimal sensitivity is 250 Hz, and Rayleigh waves generated by earthquakes are typically below 20 Hz, they do little for us in these situations. 

NATURE’S FORECASTER

Ants have a fascinating ability to seemingly anticipate both earthquakes and coming rainstorms. A recent study in Germany documented red wood ants and their propensity to build nests along active fault lines. The three year study showed that the ants, in the hours leading up to a quake, would go about their daily routine, but would stay awake and outside their mounds at night, even though this made them vulnerable to predators. The day after the quake hit, the ants would revert to their normal behavior.

Though researchers are still trying to figure out the mechanism that causes the change in behavior, it’s proposed that ants have receptors that can pick up on barely detectable changes in atmospheric gases and electromagnetic fields that are the byproduct of tremors and storms. Ants will often build up mounds around their ground holes for extra protection before heavy rains. They’ll also seek out higher nesting spots, such as the tops of tree stumps and potted plants, in an effort to avoid being washed away. For years, farmers have been tipped off to coming rain by noticing a dramatic uptick in ant activity before a downpour. 

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The Real Bay of Pigs: Big Major Cay in the Bahamas
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When most people visit the Bahamas, they’re thinking about a vacation filled with sun, sand, and swimming—not swine. But you can get all four of those things if you visit Big Major Cay.

Big Major Cay, also now known as “Pig Island” for obvious reasons, is part of the Exuma Cays in the Bahamas. Exuma includes private islands owned by Johnny Depp, Tyler Perry, Faith Hill and Tim McGraw, and David Copperfield. Despite all of the local star power, the real attraction seems to be the family of feral pigs that has established Big Major Cay as their own. It’s hard to say how many are there—some reports say it’s a family of eight, while others say the numbers are up to 40. However big the band of roaming pigs is, none of them are shy: Their chief means of survival seems to be to swim right up to boats and beg for food, which the charmed tourists are happy to provide (although there are guidelines about the best way of feeding the pigs).

No one knows exactly how the pigs got there, but there are plenty of theories. Among them: 1) A nearby resort purposely released them more than a decade ago, hoping to attract tourists. 2) Sailors dropped them off on the island, intending to dine on pork once they were able to dock for a longer of period of time. For one reason or another, the sailors never returned. 3) They’re descendants of domesticated pigs from a nearby island. When residents complained about the original domesticated pigs, their owners solved the problem by dropping them off at Big Major Cay, which was uninhabited. 4) The pigs survived a shipwreck. The ship’s passengers did not.

The purposeful tourist trap theory is probably the least likely—VICE reports that the James Bond movie Thunderball was shot on a neighboring island in the 1960s, and the swimming swine were there then.

Though multiple articles reference how “adorable” the pigs are, don’t be fooled. One captain warns, “They’ll eat anything and everything—including fingers.”

Here they are in action in a video from National Geographic:

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Christine Colby
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13 Secrets From the Ravenmaster at the Tower of London
Christine Colby
Christine Colby

Christopher Skaife is a Yeoman Warder at the Tower of London, an ancient fortress that has been used as a jail, royal residence, and more. There are 37 Yeoman Warders, popularly known as Beefeaters, but Skaife has what might be the coolest title of them all: He is the Ravenmaster. His job is to maintain the health and safety of the flock of ravens (also called an “unkindness” or a “conspiracy”) that live within the Tower walls. According to a foreboding legend with many variations, if there aren’t at least six ravens living within the Tower, both the Tower and the monarchy will fall. (No pressure, Chris!)

Skaife has worked at the Tower for 11 years, and has many stories to tell. Recently, Mental Floss visited him to learn more about his life in service of the ravens.

1. MILITARY SERVICE IS REQUIRED.

All Yeoman Warders must have at least 22 years of military service to qualify for the position and have earned a good-conduct medal. Skaife served for 24 years—he was a machine-gun specialist and is an expert in survival and interrogation resistance. He is also a qualified falconer.

Skaife started out as a regular Yeoman Warder who had no particular experience with birds. The Ravenmaster at the time "saw something in him," Skaife says, and introduced him to the ravens, who apparently liked him—and the rest is history. He did, however, have to complete a five-year apprenticeship with the previous Ravenmaster.

2. HE LIVES ON-SITE.

The Tower of London photographed at night
Christine Colby

As tradition going back 700 years, all Yeoman Warders and their families live within the Tower walls. Right now about 150 people, including a doctor and a chaplain, claim the Tower of London as their home address.

3. BUT HE’S HAD TO MOVE.

Skaife used to live next to the Bloody Tower, but had to move to a different apartment within the grounds because his first one was “too haunted.” He doesn’t really believe in ghosts, he says, but does put stock in “echoes of the past.” He once spoke to a little girl who was sitting near the raven cages, and when he turned around, she had disappeared. He also claims that things in his apartment inexplicably move around, particularly Christmas-related items.

4. THE RAVENS ENJOY SOME UNUSUAL SNACKS.

The Ravenmaster at the Tower of London bending down to feed one of his ravens
Christine Colby

The birds are fed nuts, berries, fruit, mice, rats, chicken, and blood-soaked biscuits. (“And what they nick off the tourists,” Skaife says.) He has also seen a raven attack and kill a pigeon in three minutes.

5. THEY GET A LULLABY.

Each evening, Skaife whistles a special tone to call the ravens to bed—they’re tucked into spacious, airy cages to protect them from predators such as foxes.

6. THERE’S A DIVA.

One of the ravens doesn’t join the others in their nighttime lodgings. Merlina, the star raven, is a bit friendlier to humans but doesn’t get on with the rest of the birds. She has her own private box inside the Queen’s House, which she reaches by climbing a tiny ladder.

7. ONE OF THEM HAS EARNED THE NICKNAME “THE BLACK WIDOW.”

Ravens normally pair off for life, but one of the birds at the Tower, Munin, has managed to get her first two mates killed. With both, she lured them high atop the White Tower, higher than they were capable of flying down from, since their wings are kept trimmed. Husband #1 fell to his death. The second one had better luck coasting down on his wings, but went too far and fell into the Thames, where he drowned. Munin is now partnered with a much younger male.

8. THERE IS A SECRET PUB INSIDE THE TOWER.

Only the Yeoman Warders, their families, and invited guests can go inside a secret pub on the Tower grounds. Naturally, the Yeoman Warder’s Club offers Beefeater Bitter beer and Beefeater gin. It’s lavishly decorated in police and military memorabilia, such as patches from U.S. police departments. There is also an area by the bar where a section of the wall has been dug into and encased in glass, showing items found in an archaeological excavation of the moat, such as soldiers’ discarded clay pipes, a cannonball, and some mouse skeletons.

9. … AND A SECRET HAND.

The Byward Tower, which was built in the 13th century by King Henry III, is now used as the main entrance to the Tower for visitors. It has a secret glass brick set into the wall that most people don’t notice. When you peer inside, you’ll see it contains a human hand (presumably fake). It was put in there at some point as a bit of a joke to scare children, but ended up being walled in from the other side, so is now in there permanently.

10. HE HAS A SIDE PROJECT.

Skaife considers himself primarily a storyteller, and loves sharing tales of what he calls “Victorian melodrama.” In addition to his work at the Tower, he also runs Grave Matters, a Facebook page and a blog, as a collaboration with medical historian and writer Dr. Lindsey Fitzharris. Together they post about the history of executions, torture, and punishment.

11. THE TOWER IS MUPPET-FAMOUS.

2013’s Muppets Most Wanted was the first major film to shoot inside the Tower walls. At the Yeoman Warder’s Club, you can still sit in the same booth the Muppets occupied while they were in the pub.

12. IF YOU VISIT, KEEP AN EYE ON YOUR MONEY.

Ravens are very clever and known for stealing things from tourists, especially coins. They will strut around with the coin in their beak and then bury it, while trying to hide the site from the other birds.

13. … AND ON YOUR EYES.

Skaife, who’s covered in scars from raven bites, says, “They don’t like humans at all unless they’re dying or dead. Although they do love eyes.” He once had a Twitter follower, who is an organ donor, offer his eyes to the ravens after his death. Skaife declined.

This story first ran in 2015.

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