From http://www.auschron.com/mrpants/sex.html :

"The Inca enacted laws to prevent llama drivers from having sex with their animals and enforced the laws be requiring that the llama drivers be escorted by chaperones"

This actually cued memories of my general science teacher from early high school, one Mr. Stephens, who was easily the most human teacher I've ever come across. He was very, very scottish, and did not suffer fools lightly.

Apart from his immense drive to abuse students, such as throwing black board dusters at us, calling us "demented little cockroaches", asking us to pool our brain cell power to create a single fully functioning brain etc, he also delighted in telling us wonderful stories.

One such story related how the Spanish were responsible for introducing one of the common venereal diseases (now sexually transmitted diseases) from the new world to the old world through their congresses with the locals. The locals had in turn been keeping warm and happy in the high Andes by indulging in the forbidden furry dance with llamas, alpacas (maybe even vicunas), from whom they contracted the VD originally.

I appreciated a teacher who would inform us of these things. I have no idea if it's true; the search engine bored me within seconds.