Here are three l e s s e r -known facts about llamas 1 Llamas Humming as a Social Code Llamas communicate through a series of soft humming sounds each with different meanings Mothers hum to their babies while others use hums to express curiosity stress or contentment Some researchers believe each llama may have its own unique humming dialect 2 Ancient Guard Duty While it s known that llamas are used as guard animals today ancient Incan civilizations also used them to protect their vast herds of alpacas from predators like pumas Their strong territorial instincts and loud alarm calls made them natural sentinels 3 S e l f -Regulating Pregnancy Female llamas have an unusual reproductive trait called induced ovulation They don t have a set breeding cycle instead ovulation is triggered only when they mate increasing the chances of a successful pregnancy