As with many technical anthropological terms, "clan" is loosely used in common speech to designate many different kinds of fundamental social units. The anthropological definition narrows the meaning to a unilineal descent group whose members do not trace genealogical links to a supposedly historical founding ancestor. Rights in the group are simple derived from a father or mother. Clans are usually large groups that are associated with mythical ancestors, who are very often identified as animal species that are considered sacred to the group. They may occur within a complex structure in which they are either nested into larger groups or subdivided into smaller ones in the same fashion as segmentary lineages. Where they are subdivided, the component units are often formal lineages, as in the case of the Akan which we will investigate in detail. Where clans are grouped together, the more inclusive unit is called a phratry, which is in fact a type of clan. The groups designated as "sibs" among the Dani are actually clans.