power known as ajútap. A man with such spirit power would be invulnerable in battle. In the distant past, the Aguarunas engaged in the practice of shrinking human heads to make tsantsa. Evangelical missionaries began contacting the Aguaruna in the mid-20th century, and today many Aguarunas have converted to Christianity. Biopiracy controversy In the later half of the 20th century, the arrival of Protestant and Jesuit missionaries, the building of roads, and the construction of an oil pipeline created substantial tension between the Aguaruna people, poor agricultural colonists, state agencies, and corporations. In response to new threats to their way of life the Aguaruna began to organize a political and social response to defend themselves on the basis of principles consistent with other rights of indigenous peoples. Aguaruna community organizations include the Organización Central de Comunidades Aguarunas del Alto Marañon (OCCAAM), founded in 1975, and the Consejo Aguaruna y Huambisa (CAH), an organization founded in 1977 that represents the Aguaruna and a closely related ethnic group, the Huambisa. Since then, Aguaruna community organizers have founded more than 12 local organizations (including an Aguaruna women's federation). The CAH is widely regarded the most influential political entity representing the Aguaruna (and Huambisa) peoples, and played a central role in national level indigenous movements in Peru and in the founding of the Coordinating Body of Indigenous Organizations of the Amazon Basin (COICA), which represents Amazonian peoples from all over South America. In the mid-1990s Aguaruna were involved in negotiating a novel bioprospecting agreement with a US-based pharmaceutical multinational, G.D. Searle & Company (then part of Monsanto), and a group of ethnobotanists from Washington University in St. Louis. The project involved a controversy over violations of the Aguarunas' rights over their genetic and cultural resources and to an equitable share in the potential profits derived from pharmaceuticals based on their traditional knowledge of medicinal plants. The US National Institutes of Health froze funding to the Washington University scientists. Negotiations that began between Washington University and CAH on a bioprospecting agreement failed when Washington University's Walter Lewis collected Aguaruna medicinal plants and knowledge without a benefit-sharing agreement in place, leading to claims of biopiracy. The CAH terminated its relationship with Walter Lewis, Washington University, and their US government sponsors. As Tim Cahill wrote in his Outside magazine account of a father's search for closure, "A Darkness on the River", "On the evening of January 18,