The individuals of any particular pod share the same repertoire of calls, a vocalization system called a dialect. Although scientists have noted that there is some type of structure to the calls, a dialect is not the same thing as a language. Analysis of killer whale call patterns has demonstrated substantial differences between the dialects of different pods. Pods that associate with one another may share certain calls. Pods that share calls are called a clan. Pods may share a certain level of their repertoire with other pods while other portions are unique. The more similarities they share may indicate the degree the pods and individuals are related. No two pods share the entire repertoire. Thus, each pod has its own unique dialect. In fact, the vocal repertoires of each pod remain distinct enough that scientists can identify pods by the sounds they make. Killer whales that are separated by great geographical distances have completely different dialects. An analysis of Icelandic and Norwegian killer whale pods revealed that the Icelandic population made 24 different calls and the Norwegian whales made 23 different calls, but the two populations did not share any of the same calls.