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9 Controversial Experiments In Rewilding

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Strange as it is to imagine, at one point lions roamed Europe, horses galloped over Spain, and jaguars prowled parts of the United States. The reason these animals died out wasn’t climate change, but humans hunting or destroying their territory.

Rewilding is an effort to bring species back to their native habitats, even if they haven’t lived there for thousands of years. The idea isn’t just to preserve an ecosystem, but to go back in time.

1. Wolves in Yellowstone National Park

Wolves were all but extinct throughout the 20th century in Yellowstone, but between 1995 and 1997, 41 were released and re-introduced to the park. The effect on the ecosystem was dramatic. First, the wolves thinned out the deer population, which were overeating the vegetation. Eventually, valleys and gorges turned into forests. In some cases, trees grew five times their original size. The forests not only brought in more wildlife, but also changed the rivers, which saw less soil erosion due to the new vegetation. In 2011, the gray wolf was removed from the endangered species list in Idaho and Montana and was delisted in Wyoming.

2. Wild horses in Spain

For the first time in 2000 years, 48 Retuerta horses are roaming western Spain. The endangered Retuertas are the closest relatives to the wild Iberian horses that lived in the peninsula when the Romans were around. Prior to this experiment, the only remaining Retuerta horses—150 of them—were living in a national park in southern Spain. Releasing two groups of 24 horses in their native territory may prove to increase their odds of survival. As more people abandon rural Spain for the cities, conservationists hope to bring biodiversity to a region that has been historically used as farmland.

3. Tortoises in Ile Aux Aigrettes

Ile Aux Aigrettes in the Indian Ocean was once filled with exotic speciesincluding the now-extinct dodo—until humans logged the trees and brought rats to the tiny island. In 2009, researchers introduced 19 Aldabra giant tortoises, which are similar to the extinct tortoise that used to live on Ile Aux Aigrettes. So far, the tortoises, which can get up to 660 pounds, are helping to reforest by eating the fruit of the ebony tree and depositing the seeds around the island. They also eat the nonnative plants and don’t seem bothered by the rats.

4. Trout in South London

At one time, London’s Wandle River was so polluted, locals said it would turn blue, pink, or red depending on what the tanneries were dumping at that moment. In 2003, the river, which connects to the Thames, was clean enough that trout could be released into it for the first time in 100 years. Today, you can even fish in the river, although the Wandle Valley Park says not to eat the trout “as they may hold high concentrations of heavy metals and other substances due to the river’s long industrial history.” 

5. Jaguars in Mexico

Jaguars once roamed the Southwest United States and Mexico, but these gorgeous animals (the largest cats in the Americas and the only ones that roar) have all but died out in the region. The Northern Jaguar Project is trying to change that. The bi-national nonprofit owns a 45,000-acre preserve in Sonora, Mexico that’s home to an estimated 80 to 120 jaguars. The preserve is located near Arizona, and in time these rare cats may be spotted in the U.S. once again.

6. Beavers in Wales

Beavers were hunted to extinction in Great Britain 500 years ago for their meat, fur, and scent glands. Blaeneinion, a 75-acre preserve in Wales, has introduced three beavers into the wild, and other parts of Wales may be following suit. In fact, the Welsh Beaver Project is considering releasing 30 to 40 beavers in River Rheidol sometime this year. The plan is controversial, with opponents worrying about how these dam-building animals will affect rural Welsh life.

7. Salmon in Washington

Speaking of dams, the Elwha River in Washington is a different kind of rewilding project. Instead of introducing species to the river, conservationists are removing dams so species can come back. Since 2011, dams have been removed and reservoirs have been drained and the river flows freely for the first time in a century. Not only are salmon resuming their historic swim, but the sighting of a Dungeness crab along the banks made front-page news.

8. Heck Cattle in Netherlands

Oostvaardersplassen, a 15,000-acre preserve in the Netherlands, has been stocked with animals that would have lived in the area during ancient times—or as close as you can get, anyway. For example, since aurochs went extinct in the 1600s, researchers brought in Heck cattle (which were developed, oddly enough, by the Nazis). Herds of Heck cattle now roam the preserve, as well as red deer, wild horses, and other animals. For $45, you can tour the preserve in a safari-like experience. But Oostvaardersplassen is far from perfect. Since the preserve has no top predators like wolves, rangers have to shoot animals deemed too weak to survive the winter—an issue that continues to be hotly debated in the news.

9. Wolves and bears in Scotland?

Alladale Wilderness Reserve in Scotland is a rewilding effort by multimillionaire Paul Lister. Since buying the 23,000-acre preserve, Lister has stocked it with deer, highland cattle, wild boar, and the first wild elk born in Scotland in 3000 years. There are also 800,000 indigenous trees, including Caledonian pine. (Scotland used to be so wooded that the Romans called it the “Great Wood of Caledon”—today only 1 percent of those forests survive.) Lister wants to reintroduce wolves and bears to the region, an idea that has been greeted with opposition. Despite this, Lister is moving ahead with a study on releasing two packs of 10 wolves in an enclosed 50,000-acre space. No doubt, he’s drawing on Yellowstone for inspiration.

BONUS: Horses in the Mongolian region

The Przewalski horse is the only surviving subspecies of the Asian wild horse. Stocky, with a thick neck and short mane, the horse used to roam from the Ural Mountains to Mongolia. For much of the 20th century, it was classified as “extinct in the wild.” However, these days there are herds of Przewalski’s horses in parks in Mongolia, Russia, Hungary, and China, according to Scientific American. There’s even a herd in the Chernobyl exclusion zone, which is now a wildlife refuge. The horse has been reclassified as “endangered.”

All images courtesy of Thinkstock.

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Why Tiny 'Hedgehog Highways' Are Popping Up Around London
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Hedgehogs as pets have gained popularity in recent years, but in many parts of the world, they're still wild animals. That includes London, where close to a million of the creatures roam streets, parks, and gardens, seeking out wood and vegetation to take refuge in. Now, Atlas Obscura reports that animal activists are transforming the city into a more hospitable environment for hedgehogs.

Barnes Hedgehogs, a group founded by Michel Birkenwald in the London neighborhood of Barnes four years ago, is responsible for drilling tiny "hedgehog highways" through walls around London. The passages are just wide enough for the animals to climb through, making it easier for them to travel from one green space to the next.

London's wild hedgehog population has seen a sharp decline in recent decades. Though it's hard to pin down accurate numbers for the elusive animals, surveys have shown that the British population has dwindled by tens of millions since the 1950s. This is due to factors like human development and habitat destruction by farmers who aren't fond of the unattractive shrubs, hedges, and dead wood that hedgehogs use as their homes.

When such environments are left to grow, they can still be hard for hedgehogs to access. Carving hedgehog highways through the stone partitions and wooden fences bordering parks and gardens is one way Barnes Hedgehogs is making life in the big city a little easier for its most prickly residents.

[h/t Atlas Obscura]

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Stones, Bones, and Wrecks
New Program Trains Dogs to Sniff Out Art Smugglers
Penn Vet Working Dog Center
Penn Vet Working Dog Center

Soon, the dogs you see sniffing out contraband at airports may not be searching for drugs or smuggled Spanish ham. They might be looking for stolen treasures.

K-9 Artifact Finders, a new collaboration between New Hampshire-based cultural heritage law firm Red Arch and the University of Pennsylvania, is training dogs to root out stolen antiquities looted from archaeological sites and museums. The dogs would be stopping them at borders before the items can be sold elsewhere on the black market.

The illegal antiquities trade nets more than $3 billion per year around the world, and trafficking hits countries dealing with ongoing conflict, like Syria and Iraq today, particularly hard. By one estimate, around half a million artifacts were stolen from museums and archaeological sites throughout Iraq between 2003 and 2005 alone. (Famously, the craft-supply chain Hobby Lobby was fined $3 million in 2017 for buying thousands of ancient artifacts looted from Iraq.) In Syria, the Islamic State has been known to loot and sell ancient artifacts including statues, jewelry, and art to fund its operations.

But the problem spans across the world. Between 2007 and 2016, U.S. Customs and Border Control discovered more than 7800 cultural artifacts in the U.S. looted from 30 different countries.

A yellow Lab sniffs a metal cage designed to train dogs on scent detection.
Penn Vet Working Dog Center

K-9 Artifact Finders is the brainchild of Rick St. Hilaire, the executive director of Red Arch. His non-profit firm researches cultural heritage property law and preservation policy, including studying archaeological site looting and antiquities trafficking. Back in 2015, St. Hilaire was reading an article about a working dog trained to sniff out electronics that was able to find USB drives, SD cards, and other data storage devices. He wondered, if dogs could be trained to identify the scents of inorganic materials that make up electronics, could they be trained to sniff out ancient pottery?

To find out, St. Hilaire tells Mental Floss, he contacted the Penn Vet Working Dog Center, a research and training center for detection dogs. In December 2017, Red Arch, the Working Dog Center, and the Penn Museum (which is providing the artifacts to train the dogs) launched K-9 Artifact Finders, and in late January 2018, the five dogs selected for the project began their training, starting with learning the distinct smell of ancient pottery.

“Our theory is, it is a porous material that’s going to have a lot more odor than, say, a metal,” says Cindy Otto, the executive director of the Penn Vet Working Dog Center and the project’s principal investigator.

As you might imagine, museum curators may not be keen on exposing fragile ancient materials to four Labrador retrievers and a German shepherd, and the Working Dog Center didn’t want to take any risks with the Penn Museum’s priceless artifacts. So instead of letting the dogs have free rein to sniff the materials themselves, the project is using cotton balls. The researchers seal the artifacts (broken shards of Syrian pottery) in airtight bags with a cotton ball for 72 hours, then ask the dogs to find the cotton balls in the lab. They’re being trained to disregard the smell of the cotton ball itself, the smell of the bag it was stored in, and ideally, the smell of modern-day pottery, eventually being able to zero in on the smell that distinguishes ancient pottery specifically.

A dog looks out over the metal "pinhweel" training mechanism.
Penn Vet Working Dog Center

“The dogs are responding well,” Otto tells Mental Floss, explaining that the training program is at the stage of "exposing them to the odor and having them recognize it.”

The dogs involved in the project were chosen for their calm-but-curious demeanors and sensitive noses (one also works as a drug-detection dog when she’s not training on pottery). They had to be motivated enough to want to hunt down the cotton balls, but not aggressive or easily distracted.

Right now, the dogs train three days a week, and will continue to work on their pottery-detection skills for the first stage of the project, which the researchers expect will last for the next nine months. Depending on how the first phase of the training goes, the researchers hope to be able to then take the dogs out into the field to see if they can find the odor of ancient pottery in real-life situations, like in suitcases, rather than in a laboratory setting. Eventually, they also hope to train the dogs on other types of objects, and perhaps even pinpoint the chemical signatures that make artifacts smell distinct.

Pottery-sniffing dogs won’t be showing up at airport customs or on shipping docks soon, but one day, they could be as common as drug-sniffing canines. If dogs can detect low blood sugar or find a tiny USB drive hidden in a house, surely they can figure out if you’re smuggling a sculpture made thousands of years ago in your suitcase.

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