The llama and the alpaca are natives of Central and South America. The llama has a pair of long banana-shaped ears whereas the alpaca has a pair of shorter spear-shaped ears. In addition, the llama is much bigger than the alpaca. The average weight of the llama is 300 pounds but the mean weight of the alpaca is 150 pounds only. Further, the llama has a coarse outer coat covering a soft inner coat whereas the alpaca has a fine single coat only. Could you tell whether the animals on the photos are llamas or alpacas? By the way, alpaca meats are very tasty and healthy (zero cholesterol). I ate alpaca meats almost every day throughout the trip.
It is very tempting to touch a llama or an alpaca because they are very cute and friendly. However, the Center for Disease Control (CDC) explicitly warned all travelers not to do so, otherwise you might be infected by germs or viruses that are not known by your immune system.