The Longest Fence in the World

In the vast interior of Australia lies a structure that challenges the scale of the world’s most famous landmarks. While the Burj Khalifa is the tallest building and the Boeing factory in Washington is the largest by volume, Australia holds the title for the longest fence in the world. Known as the Dingo Barrier Fence, it stretches over 5,000 kilometers—a distance greater than that between San Francisco and New York City. As reporter Shirley Wong and host Roman Mars explore, this simple wire structure has effectively split the continent into two distinct ecological universes. The story of the fence begins not with dingoes, but with rabbits. In the late 18th century, British colonizers introduced European species to Australia to make the landscape feel more like home. In 1859, a man named Thomas Austin released 24 rabbits for hunting. Within three years, the population exploded into the thousands, creating a "rabbit plague" that devastated crops and grazing lands. In 1901, the government established a "Rabbit Department" and built three massive fences to contain the spread. However, the rabbits simply hopped around or burrowed under them, rendering the project a failure. As the rabbit fences fell into disrepair, a different economic priority took hold: wool. By 1880, Australia was home to 100 million sheep, and wool became the backbone of the national economy. It was a strategic asset for the British military during World War I due to its flame-resistant and waterproof qualities. As farmers pushed their flocks into the dry, marginal regions of the interior, the sheep encountered Australia’s apex predator: the dingo. Dingoes are lean, athletic hunters that look like "buff Shiba Inus." For them, the expansion of sheep was a free buffet. For farmers, however, dingoes were a financial disaster. Because Australian sheep stations were so vast—often holding 20,000 to 100,000 animals—it was impossible to supervise the flocks. The wool industry demanded the total elimination of the predator. Australia went to "war" with the dingo, using bounties, professional trappers, and post-WWII surplus planes to drop hundreds of thousands of poisonous baits across the landscape. To finalize this separation, the government renovated the defunct rabbit fences, raising them to six feet to keep dingoes out. This created a dingo-free zone across nearly a third of the continent. While the wool industry has since declined, the fence remains a "political third rail." Tearing it down is considered "un-Australian" by many politicians, despite the $10 million annual maintenance cost and the ecological havoc it has caused. Ecologist Thomas Newsome explains that the fence has fundamentally altered the Australian environment, creating changes visible even from space. On the "dingo side," the landscape retains its natural state with shifting dunes and diverse vegetation. On the "sheep side," where the apex predator is absent, the ecosystem has suffered a "trophic cascade." Without dingoes to hunt them, kangaroo populations have exploded, leading to overgrazing that strips the land of food and shelter for other species. Furthermore, the absence of dingoes has allowed red foxes and feral cats to thrive, driving native animals like bilbies and bandicoots toward extinction. The cultural perception of the dingo has also shifted over time. For decades, they were dismissed as mere feral domestic dogs. However, research starting in the 1960s revealed they are a genetically distinct species that arrived in Australia between 4,000 and 10,000 years ago. To the Aboriginal people, dingoes—or "Wongari"—were never pests; they were protectors, companions, and partners in hunting. This tension between conservation and human activity is most evident on Gari (formerly Fraser Island), a UNESCO World Heritage site where dingoes roam free. Unlike the mainland, Gari allows tourists to see dingoes in the wild, but this has led to dangerous habituation. Tour operators often market dingoes as cute mascots, leading visitors to attempt selfies or approach them as pets. Butchula elder Boyd Blackman and officer Tessa Wa emphasize that dingoes are wild, dominant animals that must be respected. The risks of this habituation were recently highlighted by the tragic death of a Canadian tourist, Piper James, on Gari. While the exact cause of death was debated, the government responded by euthanizing a pack of ten dingoes found near the body. This decision was met with grief from the Butchula people, who were not consulted and view the dingoes as family. Scientists also warned that such culls threaten the genetic diversity of the small island population. The Dingo Barrier Fence stands as a monument to a time when humans believed they could solve ecological problems with simple physical barriers. Today, it remains a symbol of a fraught relationship. While the fence protects an aging agricultural legacy, it does so at the cost of the continent’s biodiversity. As Australia moves forward, the challenge remains how to coexist with a predator that is both a dangerous hunter and a vital, iconic part of the nation’s natural heritage.