The idea of a fence is as old as mankind itself. Lot might have changed in the way man lives now from how it lived a few thousand years back, but the reasons and motivation to use a fence are still the same. If in those days man erected a fence barrier to protect itself from wild life, unfortunately, today it is sometimes erected to protect itself from a fellow human being. Fence gave a sense of 'security' then, and it gives the same now. Apart from the innate search for security, fence comes in handy to draw boundaries, just as a purpose of demarcation between 'your' and 'my' piece of land, in that sense it has become a legal tool.
Like any other product, fences have continued to evolve with time. All kinds of materials have been used to make a fence – wood, plastic, steel, etc. one of the most innovative and effective fence is actually something which a man can make out of nature – careful trimming of cactus plant.