A tribe was a type of social group, usually smaller than a nation. They were common in civilisations that were not technologically advanced.
On Earth
The Silurians were organised into tribes (TV: The Hungry Earth [+]Loading...["The Hungry Earth (TV story)"]/Cold Blood [+]Loading...["Cold Blood (TV story)"]) or triads. Historians observed that these tribes placed themselves in cryogenic suspension at different times to avoid numerous disasters, contributing to the evolution of distinct Silurian subspecies. (PROSE: The Monster Vault [+]Loading...["The Monster Vault (novel)"]) Horlak's tribe of scholars were carriers of Raldoma Syndrome, which they were immune to, but was deadly to 99% of Silurians, including Vastra's caste. (COMIC: The Lost Dimension [+]Loading...["The Lost Dimension (comic story)"])
The Doctor encountered many human tribes throughout time and space, from the Tribe of Gum on prehistoric Earth (TV: An Unearthly Child [+]Loading...["An Unearthly Child (TV story)"]) to the Sevateem and the Tesh in the far future. (TV: The Face of Evil [+]Loading...["The Face of Evil (TV story)"]) The Tribe of the Free lived on Ravolox in 2000000. (TV: The Mysterious Planet [+]Loading...["The Mysterious Planet (TV story)"])
In the 5th century, the Roman Empire suffered attacks from many tribes, including the Goths, Ostrogoths, Visigoths, Gepids, Alans, Franks, Burgundians, and Huns. (PROSE: Combat Magicks [+]Loading...["Combat Magicks (novel)"])
In Africa, the Fourth Doctor, Sarah Jane Smith and Harry Sullivan encountered a tribe in Nyasaland. (PROSE: To Kill a Nandi Bear [+]Loading...["To Kill a Nandi Bear (short story)"])
The Efik were a tribe in the Kingdom of Dahomey. (PROSE: White Darkness [+]Loading...["White Darkness (novel)"])
In South America in 1924, George Cranleigh encountered the Kojabe tribe and another tribe led by Latoni. (TV: Black Orchid [+]Loading...["Black Orchid (TV story)"]) The Second Doctor, John and Gillian encountered a South American tribe and helped them fight off an enemy tribe. (COMIC: The TARDIS Worshippers [+]Loading...["The TARDIS Worshippers (comic story)"])
On other planets
Other species which formed tribes included Lakhotha, (PROSE: Scribbles in Chalk [+]Loading...["Scribbles in Chalk (short story)"]) Neanderthals, (TV: Ghost Light [+]Loading...["Ghost Light (TV story)"]) Swampies, (TV: The Power of Kroll [+]Loading...["The Power of Kroll (TV story)"]) and the Sycorax. (TV: The Christmas Invasion [+]Loading...["The Christmas Invasion (TV story)"]) The First Doctor, John and Gillian encountered a hostile tribe on an Earth-like planet. (COMIC: The Didus Expedition [+]Loading...["The Didus Expedition (comic story)"])