Which llama is the imposter?

Llamas are related to camels, and like camels, are used to carry goods over long distances. A llama can carry as much as 200 pounds for 12 hours a day, but are not ridden. They are commonly found in the U.S., Canada, Peru, Ecuador, Bolivia, Argentina. Llamas are native to the mountainous region of South America. Females give birth every other year, and when one llama is angry at another llama, they will stick their tongues out to express their dislike. And a llamas spit is green.

However one of these llamas is not a real llama...