I thought these were llamas when I was photographing them today.  Now I'm not sure.  I'll keep researching. Alpacas are much smaller than llamas and often have hair a "top knot" or "hair-do." Llamas have banana shaped ears while alpacas have pear shaped ears. Alpacas have shorter noses and their backs rise slightly up unlike the llama's straighter back.

Llamas and alpacas are members of the camel family (aka camelids) with a lifespan of around  20 - 25 years. Llamas were domesticated by the Incas about 4000 to 5000 years ago in the Andes Mountains in South America. 

"Today there are an estimated 7 million llamas and alpacas (in approximately equal numbers) in South America, and only a little over 100,000 llamas in the United States and Canada." Source: http://www.shagbarkridge.com/facts.html

"During the Inca period, the breeding and production of llamas was controlled by the state "Llama-Michis" or llama herders. Llamas were the property of the government and breeding was closely monitored. The hunting of llamas and alpacas was forbidden.

The Inca empire used the llama in a variety of ways. Males were sacrificed and played a prominent role in religious ceremonies. Females who could not reproduce were occasionally used for sacrifice as well. The llama fiber was collected and used to weave the course fiber product "Aluascay" for the common people. The finer alpaca and vicuna fiber was reserved for the nobility. The meat from llamas was consumed fresh and any surplus was salted and dried for later use. Some parts of the llama digestive tract were used as medicinals." Source: http://www.llamapaedia.com/origin/domestic.html

"Females are first bred at 20-24 months depending on maturity and weight. Llamas do not have a heat cycle Ovulation occurs 24-36 hours after breeding. Thus they can be bred at any time of the year. Gestation is 350 days.

A single baby call a cria (cree-ah) is normally delivered without assistance from a standing mother during daylight hours. Birth  weight is 20-35 pounds. Babies are normally up and nursing within 90 minutes. They are usually weaned at 4-6 months." Source:
http://www.shagbarkridge.com/facts.html

Directly from: http://www.llamapack.com/text/history.html
 
 "The domestication of the llama and alpaca marked the beginning of a high dependence on these animals by the Inca culture of the Andes. This dependence was somewhat analogous to the dependence the Plains Indians of North America had on the bison. The bison provided the base needs of the native cultures (food, fiber, fuel, shelter) and they served as cultural icons in spiritual and fertility rites. The important difference between the two situations is the domestication of the llama and alpaca. Domestication allowed the llamas’ additional use as a beast of burden as well as selective breeding for specific traits. The llama's adaptability and efficiency as a pack animal in the mountain terrain of the Andes made it possible to link the diverse altitude zones and to cover the great linear distances of the region. The llama was bred specifically to produce a large, strong animal for the packing function. The alpaca was bred to accentuate its naturally finer wool. The harvest of this fine wool served as the base for a significant domestic textile market. The pivotal role that llamas and alpacas played in the Incan culture and economy naturally elevated them to a highly regarded status." Source: http://www.llamapack.com/text/history.html (This website has a lot of good info on llamas.)