During spring and summer, male guanacos fight for the females, and members of the male troops ambush the family groups. These struggles make the males of the family groups mbre alert to potential attacks. During this season it is easier to hunt sex troops, while it is preferable to hunt family groups in autumn and winter. For this reason I propose that sex troops and family groups were differentially exploited according to the season. This dichotomy will be very difficult to verify archaeologically. Only the remains of newborns in archaeological sites will reflect family group exploitation, and all-male or all-female remains will indicate sex troop exploitation. Nevertheless, neither case is determinant for defining differential exploitation patterns.