Badgers live in a system of interconnected tunnels and chambers called a sett. Every badger clan has one main sett, which is used for breeding and is usually relatively large. Well-established setts have been excavated by several generations of badgers, with some setts known to be occupied for centuries. The size of the sett is influenced more by the soil type than by the number of animals living within it. In addition to the main sett, most clans have one or more secondary setts. Secondary setts are less important to the badgers than main setts, but they are useful nonetheless especially if the main sett is disturbed or there is a breakdown in the social structure within the clan. Disused setts may be taken over by rabbits or by foxes, and both these species have been known to co-habit with badgers in occupied setts. In the chambers inside the sett, the badgers make nests in which they sleep. Periodically, fresh bedding material (typically dry grass, straw, bracken or dead leaves) is collected and dragged into the sett. Setts can be located in wooded areas or scrub, although more recently there is a tendency for setts being excavated in hedgerows in areas of improved pasture.