Barbed wire is a fencing material consisting of a metal cable with regularly spaced sharp projections. The cable usually consists of two wires twisted around each other to add strength and to allow the cable to expand and contract with temperature changes without breaking. The sharp points, called barbs, usually consist of short pieces of wire twisted around one or both of the cable wires.
Fences of various kinds have been used since the earliest days of agriculture 10,000 years ago. Fences have been built from wood, earth, stone, and living plants (hedges in Europe and cactus in Latin America). Metal was not used for fencing until steel wire became available in the 19th century.
Short lengths of wire were first made at least 5,000 years ago by hammering pliable metals such as gold. By the year 1000, longer lengths of wire were made by pulling rods of soft metal, such as alloys of lead and tin, through a die of harder metal, such as iron. In modern times, until the middle of the 19th century, most wire was made from wrought iron. By 1870 improvements in steelmaking made it possible to produce large amounts of steel wire for the first time.
Steel wire was first used for fencing during the settling of the American West in areas where wood was scarce. Early wire fences consisted of single strands which were easily broken in cold weather or by wandering cattle. In 1860, Frenchman Leonce Eugene Grassin-Baledans patented the use of twisted strands of sheet metal with projecting points as a "fence protector." A similar method was patented in the United States in 1867 by Alphonso Dabb. That same year Lucien Smith and William Hunt received patents for single-stranded wire with barbs. In 1868 Michael Kelly invented the first double-stranded barbed wire, but the first commercially successful barbed wire was patented by Joseph Farwell Glidden of DeKalb, Illinois, in 1874. Similar patents were filed that same year by Jacob Haish and Leonard Ellwood, both also of DeKalb. After twenty years of legal battles, the United States Supreme Court decided in Glidden's favor, and he is often thought of as the "inventor" of barbed wire.
The use of barbed wire increased tremendously in the 1870s and 1880s, with some unfortunate side effects. In the severe winters of 1885-1886 and 1886-1887 thousands of cattle froze to death when they were unable to break through barbed wire "drift fences" intended to keep them from straying too far south. Conflicts between ranchers who wanted unfenced pastures and farmers who wanted fenced croplands escalated into fence-cutting, land-grabbing, and violent range wars. Eventually the conflict subsided when it became clear that barbed wire was becoming necessary as humans and cattle increased in number.
Barbed wire was adapted for military use during the Boer War and used in enormous quantities during World War I. Although barbed wire is often used for security, agriculture still accounts for 90% of its use. Many people collect antique barbed wire, with some rare specimens selling for hundreds of dollars. Hundreds of collectors attend the annual Barbed Wire Festival in La Crosse, Kansas, home of the Barbed Wire Museum.
Barbed wire is usually made of steel, which is an alloy of iron and a small amount of carbon. The raw materials required to manufacture steel are iron ore, coke (a carbon-rich substance produced by heating coal to a high temperature in the absence of air), and limestone. To prevent rusting, the steel wire is usually coated with zinc. Sometimes the steel is coated with aluminum, and occasionally the barbed wire itself is made of aluminum.