There is scant record of the Kagwahiv prior to their pacification by an expedition led by Nimuendajú in 1923, save for numerous melodramatic accounts of their raids on rubber tappers on the Madeira. Phonological affinities with the Urubu (Ka'apor) of Maranhão suggest an ultimate coastal origin, confirmed by legendary accounts of a journey upriver to their present location from "a land without water," crossing an expanse in which the shore was out of sight for two days (the lower Amazon above Marajó). The first historical references to them, however, do not occur until the end of the eighteenth century, when, according to Nimuendajú's researches, they were located at the confluence of the Arinos and Juruena rivers on the upper Tapajós. Nimuendajú (1924) has reconstructed the history of their ancestral tribe, denoted "Cabahyba" by Martius, from the first mention of them on the Tapajós in 1797, whence they were driven by the Portuguese-armed Mundurucu in the mid-nineteenth century, scattering westward to and distributed in fragments along the Machado (where Lévi-Strauss encountered the "Tupí Cawahíb") and to the present location of the Kagwahiv on the Madeira.
Fission was a continuing process; a Pai'i chief described to one backwoodsman how the Kutipai'i split off from them over a leadership issue. In the late nineteenth century, Byahu (who met his end ambushed by a Piraha) may have been chief over all those who call themselves Kagwahiv, but after his death they divided into subregional groups, with Diai'i holding sway in the upper Maici region, where Nimuendajú established his pacification post in 1923, and Byahu's son Pyrehakatu in the Rio Ipixuna region, which he had opened up with a few of Dyahu's sons-in-law. After pacification, separate Indian Protection Service (SPI) posts were set up at Canavial on the Ipixuna (under Antonio Lobat and a series of successors) and at the mouth of the Maici Mirim near Calamas. The SPI mandate was terminated in 1942, and the Canavial post was turned over to the appointed chief Paulinho Neves (Ijet, Pyrehakatu's son-in-law), but Garcia de Freitas stayed on as patrão at the Calamas post and was succeeded by his son Benjamin.
Groups also live near Tres Casas, on the seringal owned by the progressive descendants of the enlightened landowner Manuel Lobo (who instigated the pacification to end the state of war between the Kagwahiv and the rubber tappers) and near Nimuendajú's pacification outpost just east of Humaita. The Kagwahiv were nominally converted by Salesians and have abandoned traditional ritual but maintain their beliefs, social patterns, and food avoidances. A team of Summer Institute of Linguistics (a Protestant organization) missionary-linguists, Helen Pease and LaVera Betts, were at Canavial from after 1960 to 1976 doing linguistic research and rendering medical treatment, but they made no converts. Economically dependent on the gathering of sorva latex, a jungle product used in natural plastics, the Kagwahiv are hard-pressed economically and are diminishing in numbers. It is difficult for young people to find appropriate spouses of the opposite moiety, and the outlook for preservation of their social system is not bright. Many Kagwahiv retain a strong pride in their history and values, however, and despite the universal contempt for índios in Amazonas, the Kagwahiv retain a certain local respect for their past valor and continuing determination.