This paper examines learners' behaviors while watching online video lectures to understand learner preferences. 2927 students' 18,144 video events across 13 courses on Sakai CLE LMS, which were integrated with Kaltura Video Platform and Google Analytics, were analyzed. For the analysis of the quantitative data, one-way ANOVA, Chi-square test of independence and descriptive statistics were utilized. The main results revealed that there was a tendency toward watching interview-style video lectures completely. In addition, the percentage rate of "Watching Completely" behavior was higher in shorter videos, and a tendency toward watching long video lectures by seeking was found. According to our results, watching patterns was also affected by lecturers' characteristics. "Watching Completely" rate of female lecturers was significantly different than those of male lectures in favor of females, as well as watching in "FullScreen" mode. Furthermore, learners, who watched online video lectures completely, had higher scores on the final exam than others. Our analysis could help those who plan to optimize online video lectures in e-learning programs.