Isla Mona--not unless somebody populated the island with invasive species. PR never had monkeys to my knowledge. They do have research rhesus macaques that were let loose there in the mid 1930s, I believe, hence the name Isla Mona. They are confined to that small island. There are a lot of wild goats there, btw. Maybe that is what the OP experienced in his plate of food- goat.