Domestication of Camelids
D. Andrew Merriwether, Ph.D.
I thought people might be interested in how camelids came to be domesticated in the first place. What does it mean to be domesticated? Domesticated from what? Camelids first arose in North America between 40 and 45 million years ago. That is the first time any camelid species is found in the fossil record, and they are only found in North America from 45 million years ago up until about 3 million years ago. There were over a dozen species of camelids during that time. Three million years ago one or more of these species crossed the Bering Land Bridge that connected Alaska to Siberia and entered Asia. This landbridge appeared and disappeared many times over the millennia as sea levels have risen and fallen during ice ages. When the earth is in an "ice age" much of the Earth’s water is trapped in the form of ice as glaciers that covered much of Northern North America, Northern Europe and Northern Asia. With this water trapped as ice, the sea levels dropped dramatically, exposing much land that is now under shallow water. This includes a 1000 mile wide swath of land that was exposed that connected North America with Siberia.
Many species of animals migrated from Asia into the New World, but some species, including camelids, also went the other way, from the New World into Asia. At the same time (three million years ago), the Isthmus of Panama rose and connected North and South America together, separating the Atlantic and Pacific Oceans for the first time. About 2 million years ago other species of North American Camelids migrated into South America. These became the ancestors of the modern day vicunas and guanacos. Humans also entered the New World from Asia for the first time during a period of glaciation when the Bering Land Bridge reappeared in the last 30,000 years. Humans made it down into South America in the last 15,000 years. All humans in South America were hunter-gatherers until 6-8,000 years ago when they discovered agriculture and domesticated local animals for their use.
What were alpacas and llamas domesticated for? The New World lacked many things that had already been discovered or domesticated in the Old World. The horse went extinct in the New World tens of thousand so years before humans arrived. There were no cattle in the New World either. These did not reappear in the New World until Europeans brought them in the 1500s. This meant that the Native American peoples did not have any pack animals to carry their goods and food. They had to carry everything on their backs. This was exacerbated by the fact that the wheel had not been invented in the New World, and thus they did not have wagons or carts to help move things. This is really a problem in the Andes, where carting things up and down mountains requires a tremendous amount of labor. This led to the domestication of the llama from guanacos. The Andes also lacked large mammals except for camelids, so early man in the Andes relied on hunting wild camelids for food. Domesticating guanacos into llamas was done to make a pack animal and a reliable food source that did not require hunting. Alpacas were domesticated from vicunas as a food source, and as a source of warm wool for clothing against the harsh Andean environment.
How do we know when domestication began? First we have to think about how we go about domesticating a plant or animal. The wild progenitor species has evolved over thousands and even millions of years to be adapted to the environment it evolved in. Humans often utilize the wild versions of the progenitor species, hunting and gathering them as they find them in the environment. Domesticating means propagating a species in one place, and controlling it’s reproduction, and choosing which members get to breed to form the next generation. For plants this means selecting plants that have the traits we want, larger seed or fruit size is often selected for, as that is the portion of many plants that humans utilize. Wild tomatoes are tiny. They make cherry tomatoes look big. By selecting seeds from the wild plants with the largest fruit each season to plant for the next season, you gradually increase fruit size. For animals the process is similar. The dog was domesticated from the wolf. It is easy to think of traits we need to change in wolves to make them useful companions, guardians, and hunting assistants. It would be nice if they did not try and kill us every time they got near us. So early humans likely gathered wolf pups and selected the one that did not bite them to breed the next generation. Over many generations (about 30-40 are needed it is estimated) the wolf loses traits associated with aggressive behavior. By selecting for behavior, you are essentially selecting for hormone levels, and it turns out hormones control many aspects of development besides behavior. So muzzle length and tooth size has shrunk in dogs as compared to wolves and this relates to the effects of hormones on early development. Indeed shorter muzzle length and reduced tooth size is associated with domestication of many animals, presumably for the same reason. So in answer to the question at the beginning of this paragraph, how do we know when domestication began? We know from changes in the fossil record. The animals we kill by hunting often differ in age and sex ratios from those that we kill as part of our breeding program. We retain many females and they live a long time, while only a few males are kept alive to breed. So the age and sex distribution of remains changes with the process of domestication. We also see changes in body size, muzzle length, and fleece characters (we can see fleece in mummified alpacas and llamas that naturally mummify in the desert-like environment of the high Andes). The early ancestors of the Inca domesticated alpacas from vicunas and llamas from guanacos over 6000 years ago by choosing males with the traits they wanted to breed to their females, and eating the other males so they could not pass on their less desireable traits. The same can be done with the females. It took 5000-6000 years, but we end up with huge 500 pound llamas and 15 micron alpaca fleeces as the end products of these thousands of years of careful selective breeding. We continue this selection process in alpacas to this day, trying to improve on fineness, uniformity and fleece yield through selective breeding.
In the next column I will talk about the decimation of the alpaca and llama herds by the conquistadors, and the rebound of those herds in the 20th and 21st centuries, and the creation of the North American herd.
Departments of Anthropology and Biology
Nyala Farm Alpacas
104 Rockwell Rd
Vestal, NY 13850