A packhorse, pack horse, or sumpter refers to a horse, mule, donkey, or pony used to carry goods on its back, usually in sidebags or panniers. Typically packhorses are used to cross difficult terrain, where the absence of roads prevents the use of wheeled vehicles. Use of packhorses dates from the Neolithic period to the present day. Today, westernized nations primarily use packhorses for recreational pursuits, but they are still an important part of everyday transportation of goods throughout much of the developing world and have some military uses in rugged regions.