In agriculture, fences are used to keep animals in or out of an area. They can be made from a wide variety of materials, depending on terrain, location and animals to be confined. Most agricultural fencing averages about 4 feet (1.2 m) high, and in some places, the height and construction of wire mesh fence designed to hold livestock is mandated by law. Wire fences The principle of wire fences is that they are supported mainly by tension, being stretched between heavy strutted or guy-wired posts at ends, corners, and ideally at intervals in longer stretches (every 50 to 300 metres, 150 to 1000 feet). Between these braced posts are additional smaller wooden or metal posts which keep the wires spaced and upright, usually 3 to 6 metre (10 to 20 feet) apart, depending on the style of fencing used. Deer fence Deer and many goats can easily jump an ordinary agricultural fence, and so special fencing is needed for farming goats or deer, or to keep wild deer out of farmland and gardens. Deer fence is often made of lightweight woven wire netting nearly 2 metres (about six feet) high on lightweight posts, otherwise made like an ordinary woven wire fence.