Other changes followed the introduction of pottery, and they profoundly altered the culture of the Anasazi. More substantial and permanent houses were developed, the bow and arrow replaced the dart-thrower and dart for hunting and fighting, and handles were placed on stone axes and hammers, greatly increasing the effectiveness of these tools. Turkeys were domesticated, and their feathers replaced some of the fur in the blankets which they used for clothing. New varieties of corn, squash, and beans became known, and, more importantly, the cultivation of cotton was introduced. [Illustration: Gourd-shaped black-on-white Anasazi water jar from the period A.D. 500 to 700.] Sometime during these years of change the Anasazi adopted the practice of deforming the skulls of their children by the use of rigid cradleboards. The cradleboards of their direct ancestors were webbed and lined with soft rabbit fur, but a new conception of beauty led them to strap newborn infants onto flat, hard boards which flattened the back of the skull and broadened the forehead. These characteristics of the Anasazi developed slowly and were well established only around A.D. 750. Sometime after that date they began to live above ground, building their homes of upright poles and mud plaster. Each family’s room adjoined one or more other rooms, making more and more compact village units. In the 900’s, these pole and mud structures gave way to masonry buildings, some of which eventually became two-and three-story terraced apartment houses. The ancient pithouse was not forgotten. Its counterpart survived in almost all of the new villages in the form of a circular underground room that soon lost all resemblance to a house. Each of the larger villages had two or more of these underground rooms, which undoubtedly were ceremonial structures, serving as meeting places for men of the various clan societies and secret religious brotherhoods and for the performance of rituals. The rooms may have functioned very much like men’s clubhouses. Similar ceremonial rooms of present-day Pueblo Indians are called kivas. Much of the ceremonial activity in the ancient kivas can be inferred from the religious practices of modern Pueblo Indians. A large part of their ceremonials takes place within the privacy of the kiva and includes praying, chanting, and dancing. Details of costumes, in which feathers are extensively used, and of dance steps are important, for the whole ceremony is a prayer. The rituals are performed as petitions for rain, to insure a good harvest, or for success in hunting.