Human disturbance, social interactions and habitat constraints usually influence the behavior of wild ungulates. Poaching and habitat degradation are threats to the guanaco, a native South-American herbivore adapted to arid environments. Flight and vigilance behaviors, and guanaco-observer distances, were seasonally surveyed in mountain Andean environments, inside a protected area and surroundings. Field surveys and GIS analyses estimated environmental variables. Linear mixed models estimated probability of the mentioned behaviors and distance based on predictions about influences of human disturbance, social interactions, environmental constraints, and their changes over time. Flight and vigilance behaviors and guanaco-observer distance were higher in less protected landscapes, and near urban sites. Flight probability and guanaco-observer distance decreased over the years, being this distance shorter within the protected area. Flight decreased in summer, while vigilance increased. Vigilance was higher in groups with young, and lower in larger groups. Flight and vigilance behaviors were lower in slopes and higher in tall shrublands. These results are in agreement with hypotheses of risk-allocation, learning habituation, fitness maximization, risk detection strategy and foraging hypothesis. Social and environmental influences on guanaco behavior will probably prevail over anthropogenic influences insofar as current efforts to discourage disruptive activities are maintained in these mountain environments.