A fence built in Australia between 1880 and 1885 has divided the continent into two nearly distinct ecological zones over the past century. Originally constructed to keep out rabbits, the fence later became a barrier to protect livestock from dingoes in the fertile southeast. Stretching 5,614 kilometers, it is one of the longest human-made structures in the world and separates areas with vastly different dingo populations. Satellite images reveal a clear vegetation boundary over hundreds of kilometers, with overgrazing by kangaroos on the dingo-free side leading to less grass and degraded soil. The fence runs through three states, including 150 kilometers across the Strzelecki Desert, and is mostly made of a 180-centimeter-high metal fence with cleared ground on both sides. Maintenance of the fence involves teams of staff in New South Wales and Queensland, who conduct regular inspections. In South Australia, local committees and private landowners inspect the route every fourteen days. Legal penalties for damaging the fence include up to three months in prison for leaving a gate open and six months for damaging the structure itself. However, the fence is not effective against foxes and rabbits, which often find ways around or under it. Researchers from UNSW analyzed 32 years of NASA satellite images to see if the administrative boundary left a physical imprint on the landscape. Geographer Adrian Fisher processed the data to isolate dead vegetation, revealing significant differences in grazing pressure between the two sides of the fence. Bare soil often replaces grass cover, sometimes just a few meters from the fence. A study in the Journal of Mammalogy found that young red kangaroos on the side exposed to dingoes grew faster, suggesting that predator pressure influences the biology of prey species. Ecologists propose a simple mechanism: dingoes eat kangaroos, and kangaroos eat grass. On the dingo-free side, kangaroos are more numerous, reducing grass cover and degrading the soil. This has affected small animals like the masked lapwing. Some researchers suggest that hopping mice in dingo territory help control shrub growth by eating seeds and young shoots, and without them, sand moves more, opening up the landscape. This chain of effects may involve native rodents indirectly protected by dingoes, which keep foxes and cats in check. However, a study in Scientific Reports found no evidence that dingoes suppress foxes, cats, or monitors at the population level. The role of introduced rabbits further complicates the situation, as they may contribute to the decline of native small mammals. Farmers argue that without the fence, sheep farming in western New South Wales would be unprofitable, citing historical losses of 11,000 sheep in a single year due to dingo attacks. Ecologists like Euan Ritchie from Deakin University warn of long-term ecological costs from dingo elimination and suggest removing the fence to restore natural processes, though some advocate for more research before any changes are made. The annual maintenance cost of the fence is about 10 million Australian dollars, funded by the state and taxes on neighboring farmers. A study area showed that the fence's poor condition until 1975 allowed differences in kangaroo populations to deepen over half a century.