The guanaco (guanicoe mud) is the largest wild camelid in South America, a direct ancestor of the domesticated llama. It has a slender body, a long neck, and slender legs, adaptations that allow it to move nimbly in open, arid terrain. Its dense, woolly coat protects it from the low temperatures and strong winds of its habitat. Guanacos inhabit a wide variety of ecosystems, from the Patagonian steppes to the Andean highlands, demonstrating remarkable ecological adaptability. Their specialized digestive system allows them to efficiently exploit the scarce vegetation available in arid environments. Furthermore, they have the ability to drink brackish water and obtain moisture from the plants they consume, allowing them to survive in areas where fresh water is scarce. These physiological and behavioral adaptations have been key to their success in extreme environments.

Guanacos are social animals that live in family groups led by a dominant male, accompanied by several females and their young. Young males, upon reaching maturity, are expelled from the group and form bachelor troops or live solitary lives until they can establish their own group. During the mating season, males compete fiercely for control of females, using vocalizations and body postures to intimidate their rivals. They are diurnal animals, active during the day and resting at night. When they detect danger, they emit a high-pitched sound to alert the group and flee at high speeds, reaching up to 64 km/h. They also use visual signals, such as the position of their ears and tail, to communicate with each other.

Although the guanaco is classified as "Least Concern" by the IUCN, its populations have suffered significant declines since the arrival of European settlers, primarily due to hunting and habitat loss. In Argentina, which is home to approximately 95% of the world's population, protective measures have been implemented, including a ban on hunting in several provinces and the creation of protected areas. However, in countries such as Peru and Bolivia, populations are more fragmented and face greater risks. The main current threats include competition with domestic livestock for resources, illegal hunting, and physical barriers that impede migratory movements. The inclusion of the guanaco in CITES Appendix II seeks to regulate international trade and promote its conservation.