respected (male) leader sometimes called a chief, possibly his extended family, and other unrelated families. The band was a fundamental unit of organization, as a band was large enough to defend itself and engage in communal hunts, yet small enough to be mobile and to make decisions by consensus (leaders had only charismatic authority and no coercive power). Lodges and individuals were free to leave bands, and bands regularly split in two or merged with another, yet no one would want to be without the protection of living in a band for very long. Bands among the Peigan people in southern Alberta ranged in size from 10 to 30 lodges, or about 80 to 240 persons. By contrast, a tribe is an ethnic affiliation. A tribe is a group of people who recognize each other as compatriots due to shared language and culture. Bands from the same tribe, speaking the same language, usually relied on each other as allies against outsiders, but in Alberta tribes were not institutionalized, and decision making consisted of leaders from various bands meeting together in council to reach consensus. There are approximately nine indigenous ethnic or tribal groups in Alberta in the twenty-first century, depending on how they are counted. They are the Beaver / Daneẕaa, Blackfoot / Niitsítapi, Chipewyan / Denésoliné, Plains Cree / Paskwāwiyiniwak, Sarcee / Tsuu T'ina, Saulteaux (Plains Ojibwa) / Nakawē, Slavey / Dene Tha, Stoney / Nakoda, and the Woodland Cree / Sakāwithiniwak. Within these boundaries there is much fluidity, however, as intermarriages and bilingual bands were once very common. Scholar Neal McLeod points out that bands were loose, temporary groupings which were often polyethnic and multilingual, so that most mentions of "the Cree" by historians of previous decades actually refer to mixed Cree-Assiniboine-Saulteax groups. As well the smallpox outbreak of 1780–1781 and the whooping cough outbreak of 1819–1820 decimated many bands, forcing them to merge with neighbours. Anthropologists and others often group peoples together based on which language family their ancestral language is from, as peoples with related languages often also have cultural similarities. All of the groups presently represented in Alberta belong to one of three large language families, and are related to other languages across the continent. These are the Algonquian (Blackfoot, Cree, and Saulteaux), the Athabaskan or Dene (Beaver, Chipewyan, Slavey, and Sarcee), and the Siouan (Stoney) families. The list of tribal groups in Alberta is