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How Bugs From Australia Settled African Islands

When the Mascarene islands—Mauritius, Réunion, and Rodrigues—were born, they were blank slates. Unlike some other islands, they didn’t break off from a larger landmass, taking plants and animals with them. Instead, they rose right out of the water, formed by volcanic activity in the Indian Ocean off the coast of East Africa. Life there had to start from scratch. 

The islands collected colonizers and wayward travelers—a seed here, an egg there—over about 10 million years. Some of these species, like the islands’ most famous resident, the dodo, are no longer around, but, German zoologist Sven Bradler says, the Mascarenes are still home to a “remarkably diverse, endemic, and threatened concentration of flora and fauna.”

The islands’ location led scientists to assume that the plants and animals there arrived from nearby Madagascar and the African mainland. That’s the case for most of them, but Bradler’s research, recently published in the journal BMC Evolutionary Biology, has revealed that at least some traveled from much farther away: Australia.  

Among the Mascarenes’ animals are several types of Phasmatodeans, commonly called stick bugs or walking sticks. These large insects mimic plants for camouflage. The Mascarene stick bugs are diverse in appearance and behavior, but share some similarities with other African stick bugs. Traditionally, they’ve been placed in four different groups and descend, the thinking goes, from different, unrelated lineages of African stick bugs that all found their way to the islands at different times. 

When Bradler and his team mapped out the evolutionary histories and relationships of 120 stick bug species from around the world (including, for the first time, the ones on the Mascarenes and elsewhere in the Indian Ocean), though, they found that this traditional view was way off the mark. 

Their results suggest that the Mascarene stick bugs aren’t the descendants of several types of African bugs that made separate journeys to the islands; in fact, they don’t appear to be closely related to African stick bugs at all. Instead, they descend from a lone species of stick bug that originated in Australia, some 3000 miles away. This common ancestor was a member of bug group Lanceocercata, from which they diverged around 22 million years ago. Over time, the Mascarene insects evolved and diversified, and converged on some of the same traits and features as their African neighbors, leading to confusing similarities. 

The trip from Australia to the Mascarenes would be a long, perilous one for most animals, and stick bugs seem to be at a distinct disadvantage when it comes to such long-distance travel. While many species have wings, they’re poor flyers and can usually only use their wings to slow their descent from trees to the ground. They’re not cut out for trans-oceanic journeys—but with some luck, their eggs could pull it off. Stick insect eggs are hard-shelled and seed-like, and can survive for months at a time floating on water. The researchers think that the eggs of the Masacarene bugs’ Australian ancestor floated on a strong ocean current to get to the islands, maybe attached to a stick (how apt) that acted like a raft for them.

If you’ve been paying attention to the numbers, you might have noticed that something is amiss with this explanation: These bugs are far older than the islands they call home. While the Mascarenes’ founding stick bugs appear to have arrived around 22 million years ago, the oldest of the islands only formed 8–10 million years ago.

There's a possible explanation for this mismatched timeframe. There’s evidence that the Mascarenes had sibling islands, formed from the same volcanic hot spot, that rose above sea level around 30 million years ago and have since sunk back under the ocean. Bradler thinks that the Australian stick bug’s eggs likely landed on one of these lost islands and the bugs used them as stepping stones to get where they are now. When the colonists hatched, they evolved and speciated before moving on to the newly formed Mascarenes. 

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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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