One of the most significant differences between the New World's major areas of high culture was that Mesoamerica had no beasts of burden and wool, while the Andes had both. Four members of the camelid family - wild guanacos and vicunas, and domestic llamas and alpacas - were native to the Andes. South American populations relied on these animals for meat and wool, and as beasts of burden to transport goods all over the Andes. Bonavia's landmark study of the South American camelids is now available for the first time in English.This new edition has an updated analysis and comprehensive bibliography.

In the Spanish edition of this book, Bonavia lamented the fact that the zooarchaeological data from R.S. MacNeish's Ayacucho Project have yet to be published. In response, the Ayacucho's Project's faunal analysts, Elizabeth S. Wing and Kent V. Flannery, have added Appendices on the Ayacucho results to this English edition.