This chapter is intended to introduce veterinary students and veterinarians to the clinically relevant anatomic differences between domesticated South American camelids and domestic ungulates, particularly ruminants and horses.
In many instances their anatomy is somewhat unique, but the specific anatomy of llamas and alpacas has not been reported extensively, especially with regard to the muscular, nervous, and vascular system differences that may exist in these animals.
Because of the relative paucity of anatomic studies on the llama and alpaca, this chapter is not intended to be a complete treatise on anatomy of South American camelids but a summary of the documented anatomic differences that need to be taken into account in handling and treating llamas and alpacas. Unless otherwise mentioned, as far as the authors know camelid anatomy conforms to the general mammalian pattern exemplified by the other domestic species commonly studied.Major information sources used for this chapter include Medicine and Surgery of Camelids, Llama and Alpaca Care, and Veterinary Techniques for Llamas and Alpacas.1 In addition, a literature search was conducted of the major databases for veterinary medicine to identify papers and other sources of information specific to the llama or alpaca, and these are referenced as appropriate. Original sketches were done from photographs.
Camelids evolved in North America in the early Epocene epoch but were extinct in North America by the end of the last Ice Age. Modern camelids belong to one of two general groups: "old- world" camelids include the dromedary and the Bactrian camels, and "new-world," or South American, camelids include llamas, alpacas, vicunas, and guanacos, of which only llamas and alpacas are domesticated.
African and Asian camel ancestors are presumed to have migrated across the land bridge from North America to Asia, where they became adapted to desert conditions, while llama and alpaca ancestors migrated south to South America. Llamas and alpacas are thought to be descended from their wild relatives, the guanaco and vicuna, respectively.
These animals adapted to the high altitudes and harsh conditions of the high puna of the South American Andes. Llamas are among the longest domesticated species in the world and were first used primarily as pack animals, while alpacas were raised for their finer fleece quality. They were first brought to North America in the late 1800s but were kept mainly in zoos and private collections until the 1970s.Today they are increasing in popularity as companion and farm animals in the United States. According to U.S. Department of Agriculture livestock census data, between 2007 and 2012 the number of alpacas in the United States increased from 121,904 to 140,601, although the numbers of llamas in the United States decreased from 122,880 to 76,086 in the same time period. Alpacas commanded an exorbitant price at the height of their popularity, but prices have declined considerably; females sold for up to $70,000 in 2005 versus $1000 in 2014, and males brought up to $30,000 in 2005 and as little as $200 in 2014. Domesticated South American camelids are used for food, fiber, packing (Fig. 38.1), agility (Fig. 38.2), showing, as pets, and as projects for Scouts or 4-H groups, and llamas are also used as guard animals for sheep and other smaller livestock. The life span of llamas and alpacas is about 20 to 25 years.
South American camelids are most similar to ruminants among domestic animals, being herbivorous and having a three-chambered stomach. Camelids chew and regurgitate food during a normal gastric cycle. However, they are not small ruminants, as they have sometimes been characterized in the past.