Alpacas and llamas have common ancestry and many similarities in their reproductive systems, but are nevertheless distinct species with anatomical and physiological differences. Their reproductive anatomy has been well documented, but there is a paucity of conclusive, reliable information on their physiology. They are induced ovulators, but little is known about the factors controlling seasonal breeding. Conception rates and embryo mortality are highly variable under natural conditions. Despite the paucity of basic information there have been some successful attempts at embryo transfer and artificial insemination in both species, and at interspecific hybridisation.