Living in conditions of marginalization and illegality, the immigrants are vulnerable to crime: their resistance to this is rooted in the customs of the world they came from. Those with roots in the rural environment are directly or indirectly controlled by their communities. Those who emigrate from the cities have less capacity to resist, as the relations that connect them with their origins are more labile than the ties anchored to the land and the community, and supported by the authority of the elders. Many of the migrants spend their whole lives in periodic alternation, within the rural world, between work on the land and work outside the village; some take opportunities to go farther away, in the city and abroad. According to the National Migration Survey of 1992-93, half the rural families of Mali included one emigrant; the percentage is noticeably higher in the areas near the cities. This dense network of short-range movements escapes the analyses of migration.