Somali society is traditionally ethnically endogamous. So to extend ties of alliance, marriage is often to another ethnic Somali from a different clan. Thus, for example, a recent study observed that in 89 marriages contracted by men of the Dhulbahante clan, 55 (62%) were with women of Dhulbahante sub-clans other than those of their husbands; 30 (33.7%) were with women of surrounding clans of other clan families (Isaaq, 28; Hawiye, 3); and 3 (4.3%) were with women of other clans of the Darod clan family (Majerteen 2, Ogaden 1).

What practice is often used to bind different clans together?