Abstract The activity and space parameters (home range and use of space) for a population of Tupinambis merianae was recorded through 640 h of observation during nine months, and by monitoring 56 marked individuals. There was a significant difference in activity in the periods stipulated in this study throughout the months. Active lizards were not registered before 7:30 a.m., nor after 6:00 p.m. The greatest level of activity by the individuals occurred during November and December. Fluctuations in the population size and in the activity of the different age classes were recorded throughout the studied months. We recorded the minimum home-range of three males and two females, which varied from 0.05 to 26.44 ha. We also observed agonistic interactions. The utilization area of the animals did not vary during the studied months, but it was possible to observe gregarious behavior in spatial use. The highest daily activity occurred at the hours of higher temperatures. The positive correlation between seasonal activity and the maximum temperature (air and substrate) showed a unimodal distribution and was identical to the records from a tropical area (southeastern Brazil). It is possible that temperature is not the only environmental variable/factor that influences the seasonal activity cycle of the species. Although teiids are not considered territorial, some of our results could suggest territoriality in the studied population.