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The guanaco (Lama guanicoe) is the largest and most widely distributed wild artiodactyl (even-toed hoofed mammal) in South America. It is the most important native herbivorous species in the South American steppes and the dominant ungulate (hoofed mammal) in a fauna rich in rodents but poor in large mammal species. As of 2006, populations of guanacos were estimated to number a bit under 1 million individuals. As of 2008 guanacos were protected in 22 reserves: 14 in Argentina, 4 in Chile, 3 in Peru, and 1 in Bolivia--leaving only the Paraguayan populations unprotected. (de Lamo et al. 2001; Márin et al. 2008 and references therein)
Although guanacos traditionally played a major role in the lives of some South American aboriginal peoples, populations declined after the introduction of domestic sheep into Patagonia in the early 1900s, largely as a result of conflicts with sheep breeders. Researchers have estimated that there were about 30 to 35 million free-ranging guanacos in South America prior to colonization by Europeans. By the end of the 20th century, this number had dropped to 400,000 to 600,000, distributed over less than half of the historic range (more than 90% of the population is found in Patagonia in Argentina). Montes et al. (2006) proposed the development of sustainable methods for live-trapping and shearing free-ranging guanacos. (Montes et al. 2006 and references therein)
Guanacos are found from sea level to altitudes of about 4500 m in arid, semi-arid, hilly, mountain, steppe, and temperate forest habitats from Peru (8°S) southward to the central eastern and western slopes of the Andes and across Patagonia, including Tierra del Fuego and Navarino Island (de Lamo et al. 2001; González et al. 2006 and references therein).
The guanaco is one of four South American camelids (mammals in the camel family) recognized today, two of which are wild species, the guanaco and the vicuña (Vicugna vicugna), and two of which are domesticated forms, the alpaca (Lama pacos) and the llama (Lama glama). Wild vicuña and guanaco diverged from a shared ancestor two to three million years ago. (Wheeler 1995). At one time it was widely believed that both the domestic alpaca and the llama were derived from guanacos. However, in light of new archaeozoological evidence from 6000 to 7000 years ago in the central Peruvian Andes linking alpaca origins to the vicuña, Kadwell et al. (2001) investigated the origins of these domesticated forms using mitochondrial and nuclear DNA markers. Their results supported the hypothesis that the alpaca is derived from the vicuña (and confirmed the hypothesis that the llama is derived from the guanaco), although this work also revealed genetic evidence of historical hybridization and gene flow (at least among domesticated forms). Chromosomal analyses have also indicated that the llama was derived from the guanaco and the alpaca from the vicuña (Marín et al. 2007). Given the well established divergence between the guanaco and vicuña, many authors suggest that the correct name for the alpaca is therefore Vicugna pacos (Kadwell et al. 2001; Marín et al. 2007).