The Comanche are a Native American tribe from the Great Plains whose historic territory, known as Comancheria, consisted of present day eastern New Mexico, southeastern Colorado, southwestern Kansas, western Oklahoma, and most of northwest Texas. The Comanche people are federally recognized as the Comanche Nation, headquartered in Lawton, Oklahoma. The horse was a key element in the emergence of a distinctive Comanche culture. It was of such strategic importance that some scholars suggested that the Comanche broke away from the Shoshone and moved southward to search for additional sources of horses among the settlers of New Spain to the south (rather than search for new herds of buffalo). The Comanche may have been the first group of Plains natives to fully incorporate the horse into their culture and to have introduced the animal to the other Plains peoples. The Comanche never formed a single cohesive tribal unit, but were divided into almost a dozen autonomous groups, called bands. These groups shared the same language and culture, and rarely fought each other. They were estimated to have taken captive thousands of people from the Spanish, Mexican and American settlers in their lands. Curtis Marez suggests that this contributed to the development of mestizaje in the borderlands, as the descendants of such captives were mixed-race.